Diseases caused by bacteria. Bacterial diseases. Major human diseases caused by bacteria. Human use of bacteria

Single-celled microorganisms or bacteria (bacilli in translation from Greek) are characterized by the presence of cytoplasm, a nucleus in which there is no nuclear envelope. They enter the prokaryotes. They, like other types of microorganisms, are widespread in water soil and in the air, colonize the skin and colonize the mucous membranes of the human body and animals. Some of the bacteria are used in the food industry (for the preparation of lactic acid products). Medicine uses them in order to restore the intestinal microflora through the use of drugs, the contents of which are filled with lyophilic bacteria. Their use in biotechnology is limited to the production of compounds. The bacteria are the causative agents of scabies and hepatitis.

Saprophytic bacteria are more common than others. Dead organic residues are suitable for their nutrition, without which mineralization of organic elements - ammonification and nitrogen fixation - will not occur. This class of bacteria is represented by clostridia, azotobacters, mycobacteria, blue-green algae. With the participation of saprophytes, a process associated with the circulation of the carbon medium, oxygen, nitrogenous, phosphoric, as well as sulfur and iron, is carried out. Some of them are characterized by the ability to break down cellulose, keratin, oxidation and the formation of hydrocarbons - methane, propane. It is admitted that the idea is associated with the use of some saprophytes for the purpose of carrying out wastewater treatment processes, and as destroyers that carry out biodegradation of waste of a different nature. Saprophytes are also widely used in biotechnology. A small part of bacteria is divided into bacteria of a pathogenic and opportunistic nature. Infectious diseases of humans and animals are excited by pathogenic bacteria. In the event that the resistance of the organism is weakened, purulent-inflammatory processes are caused by opportunistic bacteria.

Bacteria are most often characterized by the presence of a thin cell wall, mainly gram-negative types; bacteria with a thick cell wall are mostly gram-positive. There are those bacteria that have no cell wall at all, such as mycoplasma. And there are archaebacteria, the difference of which is a defective cell wall, structural features of ribosomes, membranes, and also the dissimilarity of 16S-, 5S-ribosomal RNAs. Pathogens of infectious diseases are not included in the archaea. Mainly, the division of bacteria occurs according to the characteristics associated with the structure of the cell wall and its relationship with the possible variability of the Gram stain of bacteria.

Various cociform bacteria are considered gram-positive, as well as rod-shaped bacteria. These include branching actinomycetes, corynebacteria (clavate bacteria), as well as mycobacteria, represented in some cases in the branching model. Those bacteria that have lost the cell wall under the influence of antibacterial agents or due to the protective indicators of the human or animal body are called L-forms. Next to them are mycoplasmas - bacteria that do not have a cell wall.

The main feature that distinguishes bacteria is the type of respiratory process. Molecular oxygen is what determines their division into major categories. Accordingly, bacteria can be obligate aerobes, obligate anaerobes, and facultative anaerobes. Obligate aerobes spread due to the presence of oxygen, obligate anaerobes - in an environment that excludes the presence of oxygen, which is toxic to them. The development of facultative anaerobes can occur both in an environment of oxygen and in the absence of it.

What bacteria are the causative agents of diseases of plants, animals and humans

Microorganisms are the most numerous inhabitants of the planet. Among them are both useful for humans, plants and animals, and pathogenic bacteria, pathogens.

As a result of the introduction of such pathogenic microbes into living organisms, infectious diseases develop.

In order for bacteria-causative agents of diseases of plants, animals, humans to cause an infectious lesion, they must have certain properties:

pathogenicity (the ability of pathogens to penetrate a living organism, multiply and provoke the development of pathologies);

virulence (the ability of pathogens of pathology to overcome the resistance of a living organism); the higher the virulence, the fewer bacteria can cause damage;

toxicity (the ability of pathogens to produce biological poison);

contagiousness (the ability of pathogenic bacteria to be transmitted from a patient to a healthy body).

A significant factor in the characterization of bacteria-causative agents of infectious lesions is the degree of their resistance to external factors. To varying degrees, high and low temperatures, solar radiation and humidity levels affect the vital activity of bacteria.

For example, the ultraviolet component of sunlight is a potent germicidal agent. Various chemical disinfectants (chloramine, formalin) have a similar effect on the causative agents of infectious diseases, which can lead to complete death in a short time. pathogenic microflora.

By the type of toxins released, all bacteria are one of two types:

emitting exotoxins (poisonous waste products of bacteria);

sources of endotoxins (toxic substances are formed when the bodies of bacteria are destroyed).

The most famous bacteria emitting exotoxins are the causative agents of tetanus, botulism and diphtheria, and the endotoxin-producing bacteria are pathogenic agents, causative agents of typhoid fever, dysentery and cholera.

Characteristic feature infectious lesions of a living organism by bacteria, causative agents of diseases, is the incubation period.

The incubation period of a disease caused by bacteria is the time interval from the moment of infection with the pathogen until the manifestation of characteristic symptoms of the lesion. The duration of the incubation (latency) period for each disease is different, the numerical value and the degree of activity of the pathogenic bacteria that have entered the living organism are also important.

The main types of classifications of diseases

There are different classifications of lesions caused by pathogenic microorganisms.

1. Infectious diseases are divided into two groups:

anthroponosis - characteristic only for people, the source of infection is an infected person;

zoonoses - diseases characteristic of animals and humans; the infection is transmitted from an infected animal to a person; the person is not a source of infection.

2. By the place of localization of pathogenic microbes in the human body (classification by L.V. Gromashevsky):

intestinal;
blood infection;
respiratory tract damage;
damage to the outer covers.

3. Grouping of diseases by pathogen.

4. Classification based on epidemiological characteristics (routes of transmission of pathogens and methods of preventing an increase in the number of infected).

Bacteriological damage to plants

Bacteria that cause diseases of plant organisms are called phytopathogenic.

Plants can be infected in several ways:

hitting tubers;

through infected seeds;

when grafting infected cuttings and more.

In case of pathology caused by phytopathogenic microflora, various variants of damage to the plant organism by the pathogen are possible:

general, causes the death of the plant;

parts of the plant (manifests itself on the roots or in the vascular system);

local lesions - the disease does not spread beyond a single part or organ of the plant;

parenchymal infections - cause rot, burns, or stains;

the formation of neoplasms (tumors).

Most of the causative agents of plant bacteriosis are polyphagous bacteria contained in the soil. They enter plants in two ways:

through the natural physiological openings of the plant (water pores, stomata);

as a result of mechanical damage to the tissues of the plant organism.

When a plant is infected with pathogens such as phytopathogenic bacteria, several types of damage may occur at once, and in some plants the same pathogenic bacteria can cause completely different symptoms, which significantly complicates the diagnosis of the disease.

Infectious diseases of animals

Animals, like plants, are susceptible to bacterial contamination. Significant infections of animals, with the causative agent of the disease by bacteria, are:

Infected animals pose a threat to humans, since as a result of contact or through a carrier (blood-sucking), infection with the causative agent of the disease is possible.

Infectious diseases of animals that humans can contract are called zoonoses. In this case, the source of infection is an infected animal, from which, under certain conditions, the transmission of bacteria-causative agents of the disease to humans is possible.

Depending on the source of infection, all zoonoses are subdivided as:

ornithosis - the source of infection is poultry and poultry;

zooanthroponosis - a source of pathogens - these are domestic and farm animals.

Causative agents of human diseases

The human body contains more than 1000 different bacteria, and only 1% of this number falls on pathogenic microflora. While maintaining the microbial balance, the disease is not capable of developing, in addition, the human immune system suppresses the development of any pathogenic microflora. In addition, intact skin is an insurmountable barrier for pathogens of pathologies.

Bacteria-causative agents that cause human diseases are classified into several groups:

In itself, the presence of pathogenic bacteria-pathogens in the human body is not a fact of the disease - the pathogenic microflora is able to exist in the human body for a long time, without showing its destructive properties. And what is the trigger that causes disease is not yet fully understood.

Intestinal infectious diseases are among the most common - each person has suffered an infectious bowel disease during his life and far more than once. This is due to the fact that food and water are not sterile, but even more the culprits of intestinal diseases are:

non-observance of elementary sanitary standards;

failure to comply with personal hygiene standards;

violation of the rules for storing food;

the presence of vectors of infection (flies, mosquitoes, mice, etc.).

The causative agents of bacterial diseases that enter the body through the fecal-oral route of infection are a typical intestinal infection. Bacterial causative agents of gastrointestinal infections include staphylococcus, typhoid fever, cholera vibrio, salmonella and dysentery bacillus.

Regardless of the nature of the pathogenic microbes, the characteristic signs of any intestinal diseases are:

Such a reaction of the human body is protective and is designed to remove toxic substances that have entered the digestive tract as quickly as possible.

The causative agents of intestinal infections, once in the intestines, lead to disruption of the digestive processes and, as a result, inflammation of the mucous membranes of the gastrointestinal tract. Which naturally leads to the most characteristic symptom of intestinal infections - diarrhea.

Although the presence of diarrhea and vomiting is most typical for causative agents of intestinal infections, there are some diseases, such as hepatitis A, for which this symptomatology is not typical.

Bacterial infections of the intestine are life-threatening diseases - due to abundant secretions in the body, dehydration quickly sets in, which is accompanied by a massive loss of potassium (K), sodium (Na) and calcium (Ca) salts. Violation of the body's water-salt balance can quickly lead to death.

Intestinal infections caused by bacteria-pathogens are subject to therapeutic treatment using eubiotics (beneficial bacteria) and modern enterosorbents. In this case, be sure to drink plenty of fluids and a specific diet.

Infectious respiratory diseases

According to the results of the studies, the causes of respiratory diseases are viral influenza in 25% of cases, the remaining cases of acute respiratory infections include bacterial infections that cause diphtheria, scarlet fever, whooping cough, mycoplasmosis, chlamydia, legionellosis and others.

All of them are characterized by airborne droplets of infection, the source of infection with bacterial respiratory diseases are bacteria carriers and sick people.

The causative agents of respiratory bacterial diseases are various bacteria:

diphtheria - corynebacterium diphtheria, both rod-shaped and coccal forms;

scarlet fever - streptococci;

whooping cough is a rod-shaped gram-negative bacterium;

meningococcal infection - gram-negative diplococci;

tuberculosis - gram-positive mycobacteria.

Like any bacterial disease, respiratory bacterial diseases have an incubation period, after which the diseases are acute, almost all are accompanied by various kinds of cough, rhinitis, fever, pain in chest and an increase in temperature (38-39 ° C).

Respiratory diseases, causative agents of which are bacteria, are characterized not only by the defeat of the respiratory tract - infection of the genitourinary organs, musculoskeletal and nervous system, liver, skin and other organs.

Respiratory diseases caused by bacterial pathogens are treated therapeutically using various antibacterial agents, in particular, bacteriophages and antibiotics are used.

Mass diseases and ways of localization of infection

Infectious diseases by localization are divided into 4 groups:

intestinal infections with fecal-oral transmission mechanism;

respiratory diseases with airborne infection;

blood - a transmissible (through the patient's blood) way of spreading the infection;

external integument infections - infection occurs through direct contact with the patient or indirectly, through objects.

In three cases out of four, infected objects and waste products are released into the environment, where water and air contribute to the rapid spread of infections. The proportion of infectious diseases spread through food is also significant.

For example, an outbreak of a mass illness with typhoid fever or dysentery is a consequence of the entry of the pathogen either into the water supply network or into open water bodies. This is possible in case of accidents in sewerage systems or when draining wastewater.

Even in this case, mass illness can be avoided by observing basic personal hygiene measures.

Patients with infectious diseases caused by bacteria are subject to treatment in special infectious disease departments and hospitals.

In situations of mass infection, to prevent the further spread of pathogenic microflora, which is the causative agent of the disease, regime measures of a restrictive nature are carried out - quarantine and observation.

In the Middle Ages, during epidemics, infected cities and villages were simply burned along with everyone who was there to prevent the spread of pathogens.

What bacteria are the causative agents of diseases? Bacteria and humans

The main component of the bacterial cell is water. It occupies 80% of the total mass of the microorganism. However, in disputes, its content is much less - about 20%. Many bacteria tolerate a reduction in the amount of water (drying) quite well. In this case, metabolic processes slow down, and they stop multiplying. In addition, the cell contains proteins, carbohydrates, fats, as well as minerals and nucleic acids.

Bacterial cells move due to a special organ - flagella. These are thin thread-like formations, their number and location are varied. Their thickness is approximately 0.01-0.03 microns. At the same time, there are several types of them. If there is only one flagellum and it is located at one pole, such bacteria are called monotoriches. Microorganisms that have a bundle of flagella at one of the poles are monopolar lophotrichs. Those bacteria that have beams at the poles are called amphitrichs. But if the entire surface of the cell is covered with flagella, then these are peritrichous. Another way bacteria move is sliding. It is believed that this is due to the fact that the cells contract in waves.

The way bacteria reproduce is quite simple. Its essence lies in the fact that the cell is divided into two, reaching a certain size. First, it lengthens, then a transverse septum appears, sets of cells diverge at the poles. If conditions are favorable, bacteria can divide every 20 minutes. But most organisms die under the influence environment... To cope with unfavorable conditions, bacteria can form spores. In this state, they are able to maintain vital activity for thousands of years. Even in ancient mummies, bacterial spores have been found. They are formed in several types: inside, in the middle or at the end of the cell.

Spherical. These bacteria are the causative agents of various diseases. These include staphylococci (grape-shaped), streptococci (form a long chain). The latter microorganisms are the cause of inflammatory processes and diseases such as tonsillitis, otitis media, pneumonia. Staphylococcal bacteria are causative agents of diseases of the alimentary tract, purulent processes. The most dangerous representative is Staphylococcus aureus.
Spiral. They got their name from the curly shape. These include spirillae, which are a fairly harmless organism. Spirochetes look like a thin twisted thread. It is known that these bacteria are the causative agents of syphilis.
Vibrios. Representatives of this category have a slightly curved shape. They have a characteristic feature: such pathogenic bacteria are stable in an alkaline environment. Cause a disease such as cholera.
Mycoplasmas. A feature of this type is the absence of a cell membrane. Outside the host's body, they are not capable of life. The question of which disease pathogens are mycoplasma bacteria has a rather simple answer: they mainly provoke the appearance of diseases in a large cattle or plants.

Cholera is one of the most dangerous infections. It affects the digestive organs and causes severe intoxication of the body. What bacteria are the causative agents of cholera? These microorganisms were discovered by Robert Koch. Vibrio cholerae has the shape of a slightly curved stick. Distinctive feature these bacteria are highly mobile. Cholera vibrios enter the small intestine and are fixed there. There they produce protein toxins, as a result of which the water-salt balance is disturbed, the body is severely dehydrated. Bacteria are resistant to an alkaline environment, but acid is destructive for them. In addition, despite the fact that they tolerate low temperatures well, boiling kills Vibrio cholerae instantly. Infection is possible through contact with a sick person, through food or water. The incubation period is 5 days.

Lung inflammation - pretty serious diseasewhich can be fatal. Pneumonia is especially difficult for children. It is not only caused by viruses. The answer to the question of which bacteria are the causative agents of the disease is known: these are pneumococci (up to 90%). Also provoke the appearance of inflammatory processes staphylococci (about 5%) and streptococci. The bacteria are found in the nasal passages and throat.

The most common symptoms of pneumonia are high fever, shortness of breath, and general intoxication of the body. One of the most dangerous is intrauterine pneumonia. It can be provoked by group B streptococci, Staphylococcus aureus. Often, this disease occurs as a result of the flu. Bacterial pneumonia is treated with antibacterial drugs. In especially severe cases, such as the small age of the patient, hospitalization is necessary. As methods of prevention, vaccination is used, the promotion of breastfeeding for up to six months (exclusively breast milk). It is also important to maintain personal hygiene and indoor air cleaning.

Only recently was it established that chlamydia is a bacteria. What disease is caused by this type of bacteria? First of all, they are capable of causing conjunctivitis of the eye, urogenital infection, trachoma. A special type of chlamydia causes pneumonia and acute respiratory infections. Once in the host cells, microorganisms begin to divide. The entire cycle takes approximately 72 hours, with the result that the affected cell is destroyed. Such an infection is especially dangerous for women. She plays a significant role in the formation of infertility. If the fetus is infected with chlamydia, then there is a high probability of its death. That is why it is important to undergo a study before planning pregnancy, since often such an infection is asymptomatic.

Causative agents of scabies and other diseases

Quite often, amateurs wonder whether bacteria are really the causative agents of scabies. This is certainly not the case. A disease such as scabies provokes a mite, which, when it comes into contact with the skin, begins to multiply intensively, thereby causing itching. But already a complication of this ailment - pyoderma, that is, a purulent lesion of the skin - can cause bacteria of the cocci group. As a treatment, special ointments are used, and clothes and linen are disinfected.

The question of what bacteria are the causative agent of hepatitis is also relevant? Basically, hepatitis is the general name for inflammatory liver diseases. They are mainly caused by viruses. However, there is also bacterial hepatitis (with leptospirosis or syphilis). Leptospira, treponema - these bacteria are the causative agents of hepatitis.

Another serious illness is malaria. The disease is transmitted to humans through insect bites (malaria mosquitoes). It is accompanied by fever, an increase in the size of the liver (and possibly the spleen), high fever. If treatment is not started on time, then a lethal outcome is possible. The causative agents are malaria bacteria of the genus Plasmodia. Today, there are 4 types of such microorganisms. The most dangerous is the one that can cause tropical malaria. As you can see, bacteria are causative agents of diseases that have serious complications and require medical attention.

Bacteria that cause dangerous infectious diseases

At the heart of many infectious diseases is the action of pathogenic bacteria on the body. Bacteria are the causative agents of the most common infections. Famous scientists such as Alfred Koch, Leeuwenhoek, Louis Pasteur and many others devoted their activities to the study of such microorganisms.

It has been proven that the pathogenic effect on the body is exerted not by the microbes themselves, but by the toxins released by them. During illness, some of these toxic substances enter the human body during the life of the bacteria, while others are released after the death of the microbe. The study of the characteristics of the vital activity of pathogens makes it possible to most effectively influence them with medications. Bacteria can be the causative agent of very life-threatening diseases such as anthrax or plague. Let's consider the most dangerous pathogenic bacteria and diseases caused by them.

Mycobacterium tuberculosis

One of the most common bacteria is the causative agent of tuberculosis. The causative agent of this disease is mycobacterium (Koch's bacillus). The tuberculosis bacterium is 10 nm long and 0.2 to 0.4 μm in diameter. Like all bacteria that cause infectious diseases, this microorganism has a cell wall and cytoplasmic membrane, nuclear substance (DNA) and cytoplasm.

The causative agent of tuberculosis is an immobile, capsule- and spore-forming bacterium. Mycobacterium is quite resistant to the environment: for example, it can exist in water for about 5 months. The most favorable for the development of the causative agent of tuberculosis is a humid and dark environment, since sun rays cause its death within 2-3 minutes. Mycobacterium tuberculosis is resistant to alcohol and acids. To study the tuberculosis bacteria, the method of staining the material according to Tsil-Nelsen is used.

The causative agent of tuberculosis can contribute to the development of a pathological process in various body systems, but most often it is localized in the respiratory tract. The disease caused by these microbes does not have an acute onset, which is typical for other infectious diseases. This feature is associated with the absence of its own toxins in the bacteria. Clinically, this disease manifests itself:

weakness

night sweats

chills

subfebrile body temperature,

prolonged cough, sometimes with blood streaks in the sputum.

The tuberculosis bacterium enters the human body in early childhood, but the disease occurs only in one in ten cases. The body's response to the pathogen depends on immunity. The main diagnostic methods used to detect this disease are:

To detect mycobacterium tuberculosis, blood, sputum, and urine are examined. Only a positive laboratory-instrumental response can reliably indicate the development of the disease.

The following antibacterial drugs are used for the treatment of tuberculosis: rifampicin, ethambutol, isoniazid, streptomycin.

Anti-ulcer infection

Anthrax is one of the most dangerous infectious zoonotic diseases. This disease is of great epidemiological significance. The causative agent of anthrax is an immobile gram-positive bacterium that forms spores. The causative agent of anthrax (Bacillus anthracis), due to the property of forming spores, can maintain its vital activity in the environment for decades.

The clinical manifestations of anthrax are characterized by the presence of fever, specific ulcerative defects (carbuncles) on the surface of the mucous membranes and on the skin, and damage to the intestines and lungs is also possible. Accordingly, cutaneous, intestinal and pulmonary forms of anthrax are isolated. In rare cases, there is a primary septic form of anthrax. The source of infection with the causative agent of this disease is cattle.

The diagnosis of anthrax is based on data from the epidemiological history, clinical manifestations and laboratory tests. For bacteriological examination of the causative agent of anthrax, material is taken from the ulcer, sputum, feces, vomit, and blood. The laboratory response is essential for both the definitive diagnosis and treatment prescription.

Anthrax treatment is based on the introduction of specific serum, which contains antibodies. This treatment method is rather difficult for patients and is extremely dangerous. An alternative method for treating anthrax is the use of high doses of penicillin G, chloramphenicol, tetracyclines, streptomycin.

Plague is one of the deadly diseases of important epidemiological significance. Plague is characterized by fever, severe intoxication syndrome, pneumonia, septicemia and damage to the lymph nodes. The plague is caused by a gram-negative bacillus that does not have motor activity, Yersinia pestis.

Plague carriers are representatives of rodents, felines. Plague infection of a person most often occurs through fleas. The incubation period for plague can vary from 1 to 6 days. The clinical picture can be varied, in accordance with the form of manifestation of the plague: bubo, cough with profuse sputum, severe diarrhea, severe pain of various localization, skin lesions and many symptoms. For the diagnosis of plague, methods are used such as:

bacterioscopic examination,

biological sample,

the use of a diagnostic plague bacteriophage,

the immune response of the pathogen to specific antibodies.

Plague is treated with a number of antibacterial drugs, such as streptomycin, tetracycline, chloramphenicol.

Cholera is another acute quarantine disease of an infectious nature. Cholera is caused by a gram-negative, motile bacterium called Vibrio cholerae. The main feature of the causative agent of cholera is its high mobility, which determines the use of research methods such as a crushed drop or a hanging drop. Cholera is considered an intestinal infectious disease. The main manifestations of cholera are severe vomiting, diarrhea, which threaten the patient's body with significant dehydration. Symptoms of cholera are due to the ability of the causative agent of this disease to produce exotoxins.

The main diagnostic methods for detecting cholera are considered bacterioscopy and the response of the analysis to determine dehydration in the blood. Cholera treatment may include doxycycline, furazolidone, trimethoprine-sulfamethoxozole, and saline solutions.

Influenza pathogen

Another life-threatening illness is an infection such as the flu. The causative agent of influenza, in contrast to previous bacterial pathogens, is represented by the influenza virus. But it should also be considered due to the high infectivity and danger of the disease. A distinctive feature is the presence of many strains of the influenza virus.

Influenza virus infection can lead not only to the development of serious illness, but even death. Clinical manifestations of influenza are represented by a sudden increase in body temperature, fever with chills or fever (the main difference between influenza), typical manifestations of the common cold, manifestations such as dyspeptic disorders are also possible.

Persons with reduced immunity are especially prone to developing influenza. The best way to prevent infection with the causative agent of influenza is vaccination, which is carried out annually. However, not the last place in the prevention of influenza is played by methods aimed at increasing the body's immune forces.

Among the huge variety of microorganisms, you can find both friends that provide the vital activity of our body, and the worst enemies. Such life forms are divided into bacteria, viruses, fungi and protozoa. Sometimes these microorganisms are combined with the word "microbes". Bacteria are the causative agents of many diseases, some species pose a serious danger to human life. However, those organisms that live in the human body, on the contrary, help the organs to cope with their functions.

Bacteria, their structure

The simplest single-celled organisms are called bacteria. They are small in size (0.5-10 microns) and different shapes. The cell of these organisms consists of a membrane and cytoplasm. The cell membrane plays an important role in the metabolism with the environment. The cytoplasmic membrane is tightly attached to the membrane and consists of proteins, lipids and enzymes. It is responsible for the processes of excretion and entry of substances into the cell, being an osmotic barrier. The main constituent of the cytoplasm is protein. It is here that the energy processes take place that ensure the vital activity of the cell. The bacterium does not have a formed nucleus. Instead, there is a nuclear substance that contains DNA and RNA.

Cell chemistry

How microorganisms multiply. Spore formation

Depending on the form, bacteria are classified into the following types:

Spherical. These bacteria are the causative agents of various diseases. These include staphylococci (grape-shaped), streptococci (form a long chain). The latter microorganisms are the cause of inflammatory processes and diseases such as tonsillitis, otitis media, pneumonia. Staphylococcal bacteria are causative agents of diseases of the alimentary tract, purulent processes. The most dangerous representative is Staphylococcus aureus.

Rod-shaped. This view has the shape of a cylinder. They often form spores. Such microorganisms are called bacilli. Such bacteria are the causative agents of anthrax.

Spiral. They got their name from the curly shape. These include spirillae, which are a fairly harmless organism. Spirochetes look like a thin twisted thread. These bacteria are known to be the causative agents of syphilis.

Cholera is one of the most dangerous infections. It affects the digestive organs and causes severe intoxication of the body. What bacteria are the causative agents of cholera? These microorganisms were discovered by Robert Koch. Vibrio cholerae has the shape of a slightly curved stick. A distinctive feature of these bacteria is their high mobility. Cholera vibrios enter the small intestine and are fixed there. There they produce protein toxins, as a result of which the water-salt balance is disturbed, the body is severely dehydrated. Bacteria are resistant to an alkaline environment, but acid is destructive for them. In addition, despite the fact that they tolerate low temperatures well, boiling kills Vibrio cholerae instantly. Infection is possible through contact with a sick person, through food or water. The incubation period is 5 days.

Inflammation of the lungs is a fairly serious disease that can be fatal. Pneumonia is especially difficult for children. It's not just viruses that can cause it. The answer to the question of which bacteria are the causative agents of the disease is known: these are pneumococci (up to 90%). Also provoke the appearance of inflammatory processes staphylococci (about 5%) and streptococci. The bacteria are found in the nasal passages and throat.

The most common symptoms of pneumonia are fever, shortness of breath, and general intoxication of the body. One of the most dangerous is intrauterine pneumonia. It can be provoked by group B streptococci, Staphylococcus aureus. Often, this disease occurs as a result of the flu. Bacterial pneumonia is treated with antibacterial drugs. In especially severe cases, such as the small age of the patient, hospitalization is necessary. As methods of prevention, vaccination is used, the promotion of breastfeeding for up to six months (exclusively breast milk). It is also important to maintain personal hygiene and indoor air purification.

Another serious illness is malaria. The disease is transmitted to humans through insect bites (malaria mosquitoes). It is accompanied by fever, an increase in the size of the liver (and possibly the spleen), high fever. If treatment is not started on time, then death is possible. The causative agents are malaria bacteria of the genus Plasmodia. Today, there are 4 types of such microorganisms. The most dangerous is the one that can cause tropical malaria. As you can see, bacteria are causative agents of diseases that have serious complications and require medical attention.

Online Q&A

Question: What is hepatitis?

Answer: Hepatitis is an inflammation of the liver. The condition can be self-limiting or lead to fibrosis (scarring), cirrhosis, or liver cancer. The most common pathogens of hepatitis in the world are hepatitis viruses, but other infections, toxic substances (such as alcohol and some drugs) and autoimmune diseases can also cause it.

There are 5 main hepatitis viruses, called types A, B, C, D, and E. These 5 types pose a huge challenge because of the burden of disease and death they cause and their potential to cause disease outbreaks and epidemic spread. ... In particular, types B and C cause chronic disease in hundreds of millions of people and, together, are the most common causes of cirrhosis and liver cancer.

Hepatitis A and E are usually caused by eating contaminated food or water. Hepatitis B, C, and D usually result from parenteral contact with infected body fluids. Common modes of transmission of these viruses include transfusion of contaminated blood or blood products, invasive medical procedures using contaminated equipment, and, for hepatitis B, transmission from mother to child during childbirth, family member to child, and sexual contact.

Acute infection may be symptomatic or asymptomatic, or may include symptoms such as jaundice (yellowing of the skin and eyes), dark urine, excessive fatigue, nausea, vomiting, and abdominal pain.

Question: What are the different hepatitis viruses?

Answer: Scientists have identified 5 separate hepatitis viruses, identified by the letters A, B, C, D and E. They all lead to the development of liver disease, but there are significant differences between them.

Hepatitis A virus (HAV) is present in the faeces of infected people and is most commonly transmitted through the consumption of contaminated food or water. HAV can also be spread in some types of sexual relationships. In many cases, infections are mild, most people recover completely and remain immune to subsequent HAV infections. However, HAV infections can be severe and life-threatening. Most people in poorly sanitized areas of the world are infected with this virus. There are safe and effective vaccines available to prevent HAV.

Hepatitis B virus (HBV) spread by contact with infected blood, semen, and other body fluids. HBV can be passed from an infected mother to her baby during childbirth, or from a family member to a young child. Transmission of infection can also occur through transfusion of blood and blood products contaminated with HBV, injection with contaminated equipment during medical procedures, and injecting drug use. HBV also poses a hazard to healthcare workers who suffer needle stick injuries while caring for HBV-infected patients. There is a safe and effective vaccine to prevent HBV.

Hepatitis C virus (HCV)is mainly transmitted by contact with infected blood. This can occur through transfusion of HCV-contaminated blood and blood products, injection with contaminated equipment during medical procedures, and injecting drug use. Sexual transmission is also possible, but this happens much less often. There is no vaccine against HCV.

Hepatitis D virus (HDV) can only infect people who are infected with HBV. Double infection with HDV and HBV can lead to more serious illness and worse outcome. Safe and effective hepatitis B vaccines provide protection against HDV infection.

Hepatitis E Virus (HEV)Like HAV, it is most commonly transmitted through the consumption of contaminated food or water. HEV often leads to outbreaks of hepatitis in developing parts of the world and is increasingly recognized as a significant cause of disease in developing countries. Safe and effective vaccines have been developed to prevent HEV infection but are not widely available.

Microorganisms are the most numerous inhabitants of the planet. Among them are both useful for humans, plants and animals, and pathogenic bacteria, pathogens.

As a result of the introduction of such pathogenic microbes into living organisms, infectious diseases develop.

In order for bacteria-causative agents of diseases of plants, animals, humans to cause an infectious lesion, they must have certain properties:

pathogenicity (the ability of pathogens to penetrate a living organism, multiply and provoke the development of pathologies);
virulence (the ability of pathogens of pathology to overcome the resistance of a living organism); the higher the virulence, the fewer bacteria can cause damage;
toxicity (the ability of pathogens to produce biological poison);
contagiousness (the ability of pathogenic bacteria to be transmitted from a patient to a healthy body).

For example, the ultraviolet component of sunlight is a potent germicidal agent. A similar effect on the causative agents of infectious diseases is exerted by various chemical disinfectants (chloramine, formalin), which can lead to the complete death of pathogenic microflora in a short time.

By the type of toxins released, all bacteria are one of two types:

emitting exotoxins (poisonous waste products of bacteria);
sources of endotoxins (toxic substances are formed when the bodies of bacteria are destroyed).

Bacterial toxins

A characteristic feature of infectious lesions of a living organism by bacteria, pathogens, is the incubation period.

There are different classifications of lesions caused by pathogenic microorganisms.

1. Infectious diseases are divided into two groups:

anthroponosis - characteristic only for people, the source of infection is an infected person;
zoonoses - diseases characteristic of animals and humans; the infection is transmitted from an infected animal to a person; the person is not a source of infection.

2. By the place of localization of pathogenic microbes in the human body (classification by L.V. Gromashevsky):

intestinal;
blood infection;
respiratory tract damage;
damage to the outer covers.

3. Grouping of diseases by pathogen.

4. Classification based on epidemiological characteristics (routes of transmission of pathogens and methods of preventing an increase in the number of infected).

Bacteriological damage to plants

Bacteria that cause diseases of plant organisms are called phytopathogenic.

Plants can be infected in several ways:

hitting tubers;
through infected seeds;
when grafting infected cuttings and more.

In case of pathology caused by phytopathogenic microflora, various variants of damage to the plant organism by the pathogen are possible:

general, causes the death of the plant;
parts of the plant (manifests itself on the roots or in the vascular system);
local lesions - the disease does not spread beyond a single part or organ of the plant;
parenchymal infections - cause rot, burns, or stains;
the formation of neoplasms (tumors).

Signs of chlorosis on plant leaves

Most of the causative agents of plant bacteriosis are polyphagous bacteria contained in the soil. They enter plants in two ways:

through the natural physiological openings of the plant (water pores, stomata);
as a result of mechanical damage to the tissues of the plant organism.

Infectious diseases of animals

Animals, like plants, are susceptible to bacterial contamination. Significant infections of animals, with the causative agent of the disease by bacteria, are:

plague;
anthrax;
tularemia;
brucellosis;
salmonellosis and others.

Infected animals pose a threat to humans, since as a result of contact or through a carrier (blood-sucking), infection with the causative agent of the disease is possible.

Infectious diseases of animals that humans can contract are called zoonoses. In this case, the source of infection is an infected animal, from which, under certain conditions, the transmission of bacteria-causative agents of the disease to humans is possible.

Depending on the source of infection, all zoonoses are subdivided as:

ornithosis - the source of infection is poultry and poultry;
zooanthroponosis - a source of pathogens - these are domestic and farm animals.

Causative agents of human diseases

Bacteria-causative agents that cause human diseases are classified into several groups:

Gastrointestinal infections

non-observance of elementary sanitary standards;
failure to comply with personal hygiene standards;
violation of the rules for storing food;
the presence of vectors of infection (flies, mosquitoes, mice, etc.).

Regardless of the nature of the pathogenic microbes, the characteristic signs of any intestinal diseases are:

diarrhea;
nausea, vomiting.

Such a reaction of the human body is protective and is designed to remove toxic substances that have entered the digestive tract as quickly as possible.

Infectious respiratory diseases

All of them are characterized by airborne droplets of infection, the source of infection with bacterial respiratory diseases are bacteria carriers and sick people.

The causative agents of respiratory bacterial diseases are various bacteria:

diphtheria - corynebacterium diphtheria, both rod-shaped and coccal forms;
scarlet fever - streptococci;
whooping cough is a rod-shaped gram-negative bacterium;
meningococcal infection - gram-negative diplococci;
tuberculosis - gram-positive mycobacteria.

Like any bacterial disease, respiratory bacterial diseases have an incubation period, after which the diseases pass acutely, almost all are accompanied by various kinds of cough, rhinitis, feverish conditions, pain in the chest and fever (38-39 ° C).

Respiratory diseases, the causative agents of which are bacteria, are characterized not only by damage to the respiratory tract - it is possible to infect the genitourinary organs, the musculoskeletal and nervous system, liver, skin and other organs.

Respiratory diseases caused by bacterial pathogens are treated therapeutically using various antibacterial agents, in particular, bacteriophages and antibiotics are used.

Mass diseases and ways of localization of infection

Infectious diseases by localization are divided into 4 groups:

intestinal infections with fecal-oral transmission mechanism;
respiratory diseases with airborne infection;
blood - a transmissible (through the patient's blood) way of spreading the infection;
external integument infections - infection occurs through direct contact with the patient or indirectly, through objects.

Even in this case, mass illness can be avoided by observing basic personal hygiene measures.

Patients with infectious diseases caused by bacteria are subject to treatment in special infectious disease departments and hospitals.

In the Middle Ages, during epidemics, infected cities and villages were simply burned along with everyone who was there to prevent the spread of pathogens.

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GBOU AO SPO Astrakhan Technological College

Service department

By discipline

"Sanitation and Hygiene"

On the topic: Microorganisms-causative agents of infectious diseases

Performed

Group student

Telesheva Sabina

Introduction

The idea of \u200b\u200bthe infectiousness of diseases such as plague, cholera, smallpox and many others, as well as the assumption of the living nature of the infectious principle transmitted from the sick to the healthy, existed even among the ancient peoples. The plague epidemic of 1347-1352, known in history as the Black Death, further reinforced this view. Particularly noteworthy was the contact spread of syphilis, which appeared in Europe in the Middle Ages, as well as typhus.

During this period of development of medicine, the symptoms of diseases, their infectiousness, are mainly described; the first messages appear about the immunity of people to a previously transferred disease. However, the development of medical knowledge, like other sciences, in the Middle Ages was very difficult by the domination of the church, "church dogma was the starting point and basis of all thinking."

The doctrine of infectious diseases developed along with advances in other areas of scientific knowledge and was determined, like them, by the development of the socio-economic basis of society. The final solution to the question of the existence of living beings invisible to the naked eye belongs to the Dutch naturalist Antonio van Leeuwenhoek (1632-1723), who discovered the world of the smallest creatures unknown to him. But even after this discovery, microbes were not yet finally recognized as causative agents of infectious diseases, although individual researchers tried to establish their role. Thus, the Russian doctor D.S.Samoilovich (1744-1805) proved the infectiousness of the plague and disinfected the patients' belongings, and also tried to vaccinate against this disease. In 1782, using a microscope, he looked for the causative agents of the plague.

The middle of the 19th century was characterized by the rapid development of microbiology. The great French scientist Louis Pasteur (1822-1895) established the participation of microbes in fermentation and decay, that is, in the processes that constantly occur in nature; he proved the impossibility of the spontaneous generation of microbes, scientifically substantiated and introduced sterilization and pasteurization into practice. Pasteur discovered the causative agents of chicken cholera, septicemia, osteomyelitis, etc. Pasteur developed a method for preparing vaccines by artificially attenuating (attenuating) virulent microbes to prevent infectious diseases - a method that is still used today. He prepared vaccines against anthrax and rabies.

In the further development of microbiology, great merit belongs to the German scientist Robert Koch: (1843-1910). The methods of bacteriological diagnostics developed by him made it possible to discover the causative agents of many infectious diseases.

Finally, in 1892, viruses were discovered by the Russian scientist D.I.Ivanovskii (1864-1920).

Simultaneously with the development of medical microbiology, the clinical knowledge of doctors has improved. In 1829, Charles Louis described in detail the clinic of typhoid fever, separating this disease from the group of "fevers" and "fevers", in which all the diseases that occurred with high fever had been combined before. In 1856 typhus was isolated from the group of "fever", in 1865 - relapsing fever. Great services in the field of studying infectious diseases belong to the outstanding Russian professors S.P.Botkin, A.A.Ostroumov, N.F. Filatov. SP Botkin established the infectious nature of the so-called catarrhal jaundice - a disease now known as Botkin's disease. He described the clinical features of typhoid fever. His student prof. N.N. Vasiliev (1852-1891) identified "infectious jaundice" (ictero-hemorrhagic leptospirosis) as an independent disease. Excellent pediatrician prof. NF Filatov first studied and described glandular fever - infectious mononucleosis, a disease now known as Filatov's disease.

Epidemiology also developed successfully. Thanks to I.I.Mechnikov (1845-1916) and many other researchers at the end of the last century, a harmonious doctrine of immunity (immunity) in infectious diseases was created. Discovered by I.I.Mechnikov in 1882-1883. the phenomenon of phagocytosis, which laid the foundation for the doctrine of immunity, opened up prospects for the prevention and treatment of infectious diseases. These discoveries made it possible to develop and apply in the clinic serological studies (agglutination reactions, precipitation, etc.) for laboratory diagnosis of infectious diseases. Much credit in the development of immunology and the theory of infection belongs to N.F. Gamaleya (1859-1949), who also discovered the phenomenon of bacteriophagy.

Wide opportunities for the development of scientifically based methods of combating infectious diseases opened up in our country after the Great October Socialist Revolution. The fight against infectious diseases in the USSR is widespread. A network of anti-epidemic institutions was created, infectious diseases hospitals were opened, departments of infectious diseases were established in medical institutes, special research institutes were created to study infectious diseases, methods of their prevention and complete elimination.

The great merit of Soviet scientists in the study of the specific prevention of infectious diseases. Currently, highly effective live vaccines against brucellosis, smallpox, anthrax, tularemia, plague, leptospirosis and some other diseases are successfully used. In 1963, Soviet scientists A.A. Smorodintsev and M.P. Chumakov were awarded the Lenin Prize for the development of a vaccine against poliomyelitis.

Various chemicals have long been used to treat infectious diseases. Earlier, others began to use an infusion of cinchona bark for the treatment of malaria, and since 1821 - quinine. At the beginning of the 20th century, arsenic preparations (arsacetin, salvarsan, neosalvarsan, etc.) were released, which are still successfully used to treat syphilis and anthrax. In the 30s of this century, sulfa drugs (streptocide, sulfidine, etc.) were obtained, which marked a new period in the treatment of infectious patients. Finally, in 1941, the first antibiotic, penicillin, was obtained, the value of which can hardly be overestimated. To obtain penicillin, the work of domestic scientists V.A.Manassein, A.G. Polotebnov, and the English microbiologist Alexander Flemming was important. In 1944, streptomycin was obtained, in 1948 - chloromycetin, in 1948-1952. - tetracycline drugs. Antibiotics are now the main treatment for most infectious diseases.

Along with advances in the prevention and treatment of many infectious diseases, there are currently significant advances in their clinical study. Only in recent years have several new infectious diseases, mainly of viral etiology, been discovered and studied. Much attention is paid to issues of pathogenesis, clinical features of the modern course of infectious diseases, in particular in vaccinated; treatment methods are being improved.

Research in the field of infectious pathology continues on a broad front.

The reasons for their occurrence. Transmission mechanism

The process of the spread of infectious diseases in the human collective is a complex phenomenon, which, in addition to purely biological aspects (properties of the pathogen and the state of the human body), is also greatly influenced by social factors: the material condition of the people, population density, cultural skills, the nature of food and water supply , profession, etc. The process of the spread of infectious diseases consists of three interacting links: 1) a source of infection emitting a microbe-pathogen or a virus; 2) the mechanism of transmission of pathogens of infectious diseases; 3) the susceptibility of the population. Without these links or factors cannot arise new cases of infection with infectious diseases.

The source of infection in most diseases is a sick person or sick animal, from the body of which the pathogen is excreted in one way or another physiological (exhalation, urination, defecation) or pathological (cough, vomiting) way.

The way of isolating the pathogen from a sick organism is closely related to the place of its predominant presence in the body, its localization. So, with intestinal infectious diseases, pathogens are released from the intestines during bowel movements; in case of damage to the respiratory tract, the pathogen is excreted from the body when coughing and sneezing; when the pathogen is localized in the blood, it can enter another organism when bitten by blood-sucking insects, etc.

It should be borne in mind that the intensity of the excretion of pathogens in different periods of the disease is different. In some diseases, they begin to stand out already at the end of the incubation period (measles in humans, rabies in animals, etc.). But the greatest epidemic significance in all acute infectious diseases is at the height of the disease, when the release of microbes, as a rule, occurs especially intensively.

In a number of infectious diseases (typhoid fever, paratyphoid fever, dysentery, diphtheria), pathogens can be intensively released during the recovery period (convalescence).

Sometimes, even after recovery, a person can remain a source of infection for a long time. Such people are called bacteria carriers. In addition, the so-called healthy bacteria carriers are observed - persons who either themselves did not get sick, or suffered the disease in the mildest form, in connection with which it remained unrecognized, but became carriers of bacteria.

A carrier bacterium is a practically healthy person, but carries in itself and excretes pathogens. Distinguish between acute carriage, if it, as in typhoid fever, lasts 2-3 months, and chronic, when a person who has been ill for decades releases the pathogen into the external environment. Allocation can be permanent, but more often it is periodic. Apparently, the greatest epidemiological danger is posed by bacteria carriers, as well as patients with erased, atypical, light forms diseases that do not go to the doctor, transferring the disease on the legs and dispersing pathogens around themselves (this is especially often observed in patients with influenza and dysentery).

Transfer mechanism. After the pathogen is released from the source of infection (infected organism) into the external environment, it may die or remain in it for a long time until it gets to a new individual. In the chain of movement of the pathogen from the patient to the healthy, the duration of stay and the ability of the pathogen to exist in the external environment are of great importance. It was during this period that the causative agents of the disease - microorganisms - are the most accessible to influence them, they are easier to destroy. Many of them are perniciously affected by the sun's rays, light, and drying. Very quickly, within a few minutes, causative agents of influenza, epidemic meningitis, and gonorrhea die in the external environment. Other microorganisms, on the contrary, have adapted to maintain their viability in the external environment for a long time. For example, the causative agents of anthrax, tetanus and botulism in the form of spores can persist in the soil for years or even decades. Mycobacterium tuberculosis remain for weeks in a dried state in dust, sputum, etc. In food products, for example, meat, milk, various creams, the causative agents of many infectious diseases can live for a long time and even multiply. The degree of resistance of pathogens in the external environment is of great importance in epidemiology, in particular in the selection and development of a set of anti-epidemic measures.

In the transmission of an infectious principle (pathogens), various objects of the external environment are involved - water, air, food, soil, etc., which are called factors of transmission of infection. The routes of transmission of pathogens of infectious diseases are extremely diverse. They can be combined into four groups, depending on the mechanism and routes of transmission.

1. The contact route of transmission (through the outer cover) is possible in cases where pathogens are transmitted through the contact of a patient or his secretions with a healthy person. Distinguish between direct contact, that is, one in which the pathogen is transmitted by direct contact of the source of infection with a healthy organism (bite or drooling of a person by a rabid animal, sexual transmission of sexually transmitted diseases, etc.), and indirect contact, in which the infection transmitted through household and industrial items (for example, a person can become infected with anthrax through a fur collar or other fur and leather products contaminated with anthrax bacteria).

By indirect contact, only infectious diseases can be transmitted, the pathogens of which are resistant to the effects of the external environment. An example of the long-term preservation of microbes with indirect contact is the spores of the causative agents of anthrax and tetanus, which sometimes persist in the soil for decades.

2. The fecal-oral transmission mechanism is of great importance in the transmission of infectious diseases. In this case, pathogens are excreted from the body of people with feces, and infection occurs through the mouth with food and water contaminated with feces.

The food route of transmission of infectious diseases is one of the most common. In this way, both pathogens of bacterial infectious diseases (typhoid fever, paratyphoid fever, cholera, dysentery, brucellosis, etc.), and some viral diseases (Botkin's disease, poliomyelitis, Bornholm's disease) are transmitted. In this case, pathogens can get on food in various ways. The role of dirty hands does not require explanation: infection can occur both from a sick person or a carrier of bacteria, and from people around who do not follow the rules of personal hygiene. If their hands are contaminated with the faeces of a sick person or a bacteriological carrier containing pathogens, then when processing food, these persons can infect them. Intestinal infectious diseases are therefore called diseases of dirty hands for a reason.

Infection can occur through infected animal products (milk and meat from brucellosis animals, animal meat or duck eggs containing salmonella bacteria, etc.). Pathogens can get on animal carcasses when cutting them on tables contaminated with bacteria, during improper storage and transportation, etc. It should be remembered that food products can not only retain microbes, but also serve as a breeding ground for the reproduction and accumulation of microorganisms ( milk, meat and fish products, canned food, various creams).

Flies play a certain role in the spread of intestinal infectious diseases that have a fecal-oral mechanism of infection. Sitting on dirty bed liners, various impurities, flies contaminate their legs and suck in pathogenic bacteria into the intestinal tube, and then transfer and excrete them onto food and dishes. Microbes on the surface of the fly's body and in the intestines remain viable for 2-3 days. Contamination occurs when you eat contaminated food and use contaminated dishes. Therefore, the destruction of flies is not only a general hygienic measure, but also pursues the goal of preventing intestinal infectious diseases. The presence of flies in an infectious diseases hospital or department is unacceptable.

4. Close to food is the waterway of transmission of infectious diseases. Cholera, typhoid fever and paratyphoid fever, dysentery, tularemia, brucellosis, leptospirosis, etc. can be transmitted through water contaminated with feces. The transmission of pathogens occurs both when drinking contaminated water, and when washing food, as well as when bathing in it.

5. Transmission through the air occurs in infectious diseases localized mainly in the respiratory tract: measles, whooping cough, epidemic meningitis, influenza, natural smallpox, pneumonic plague, diphtheria, scarlet fever, etc. Most of them are carried with droplets of mucus - drip infection. Pathogens transmitted in this way are usually unstable in the external environment and quickly die in it. Some germs can also be transmitted with dust particles - dust infection. This route of transmission is possible only in infectious diseases, the causative agents of which are resistant to desiccation (anthrax, tularemia, tuberculosis, Q fever, smallpox, etc.).

Some infectious diseases are spread by blood-sucking arthropods. Having sucked blood from a sick person or animal containing pathogens, the carrier remains infectious for a long time. Then attacking a healthy person, the carrier infects him. Thus, fleas transmit the plague, lice - typhus and relapsing fever, ticks - encephalitis, etc.

Finally, pathogens can be carried by flying insect transmitters; this is the so-called transmission path. In some cases, insects can only be simple mechanical carriers of microbes. In their body, the development and reproduction of pathogens does not occur. These include flies that carry intestinal pathogens from faeces to food. In other cases, the development or reproduction and accumulation of pathogens occurs in the body of insects (louse - with typhus and relapsing fever, flea - with plague, mosquito - with malaria). In such cases, insects are intermediate hosts, and the main reservoirs, that is, sources of infection, are animals or a sick person. Finally, the pathogen can persist for a long time in the body of insects, transmitted by the embryonic route through the laid eggs (transovarial). This is how the virus of taiga encephalitis is transmitted from one generation of ticks to the next. For some infections, the transmission route is soil. For pathogens of intestinal infections, it is only a place of more or less short-term stay, from where they can then penetrate into water supply sources; for spore-forming microbes - anthrax, tetanus and other wound infections - the soil is a place of long-term storage.

Classification of infectious diseases

The causative agents of infectious diseases, as we saw above, are transmitted from patients in healthy different ways, that is, for each infection a certain transmission mechanism is characteristic. The mechanism of transmission of infection is laid by L.V. Gromashevsky as the basis for the classification of infectious diseases. According to the classification of L.V. Gromashevsky, infectious diseases are divided into four groups.

I. Intestinal infections. The main source of infection is a sick person or a carrier of bacteria that excrete huge amounts of pathogens with feces. With some intestinal infectious diseases, it is also possible to excrete the pathogen with vomit (cholera), with urine (typhoid fever).

The contagious principle enters the body through the mouth along with food or drinking water contaminated in the external environment in one way or another. The mechanism of transmission of the infectious principle in intestinal infections shown schematically in Fig. one.

Intestinal infectious diseases include typhoid fever, paratyphoid fever A and B, dysentery, amebiasis, toxicoinfections, cholera, Botkin's disease, poliomyelitis, etc.

Figure: 1. Diagram of the mechanism of transmission of the infectious principle in intestinal infections according to L. V. Gromashevsky.

A - an infected organism; B - a healthy body; 1 - the act of removing the pathogen (defecation); 2 - the presence of the pathogen outside the body; 3 - the act of introducing the pathogen.

II. Respiratory tract infections. The source of infection is a sick person or a carrier of bacteria. The inflammatory process on the mucous membranes of the upper respiratory tract causes coughing and sneezing, which causes the massive release of an infectious principle with droplets of mucus into the surrounding air. The pathogen enters the body of a healthy person by inhaling air containing contaminated droplets (Fig. 2). Respiratory tract infections include influenza, infectious mononucleosis, smallpox, epidemic meningitis, and most childhood infections.

III. Blood infections. The causative agents of this group of diseases are mainly localized in the blood and lymph. An infection from the patient's blood can enter the bloodstream

Figure: 2. Scheme of the transmission mechanism of the infectious principle in respiratory tract infections (according to L. V. Gromashevsky).

A - an infected organism; B - a healthy body; 1 - the act of removing the pathogen (exhalation); 2 - the presence of the pathogen outside the body; 3 - the act of introducing the pathogen (inhalation).

healthy only with the help of blood-sucking carriers (Fig. 3). A person with an infection of this group is practically not dangerous to others in the absence of a carrier. An exception is plague (pulmonary form), which is highly contagious to others.

The group of blood infections includes typhus and relapsing fever, tick-borne rickettsiosis, seasonal encephalitis, malaria, leishmaniasis and other diseases.

IV. Skin infections. The contagious onset usually penetrates through the damaged outer integument. These include sexually transmitted diseases; rabies and sodoku, infection with which occurs when bitten by sick animals; tetanus, the causative agent of which enters the body by wound; anthrax, transmitted by direct

Figure: 3. Diagram of the mechanism of transmission of the infectious principle in blood infections (according to L. V. Gromashevsky).

A - an infected organism; B - a healthy body; 1 - the act of removing the pathogen (sucking blood by arthropod vectors); 2 - the presence of the pathogen in the organism of the carrier (the second biological host); 3 - the act of introducing the pathogen.

pathogen infectious microorganism

contact from animals or through household items contaminated with spores; glanders and foot and mouth disease, in which infection occurs through the mucous membranes, etc.

It should be noted that in some diseases (plague, tularemia, anthrax, etc.) there may be a multiple mechanism of transmission of infection.

Conclusion

Measures to combat infectious diseases can be effective and give reliable results in the shortest possible time only if they are planned and comprehensively carried out, that is, they are systematically carried out according to a pre-drawn up plan, and not from case to case. Anti-epidemic measures should be based on the obligatory consideration of specific local conditions and the characteristics of the transmission mechanism of the causative agents of this infectious disease, the degree of susceptibility of the human community and many other factors. To this end, the main attention should be paid in each case to the most accessible link in the epidemic chain for our impact. So, in case of malaria, it is the destruction of pathogens (plasmodia of malaria) in the body of a sick person with the help of therapeutic agents and the destruction of mosquito vectors; in case of food toxicoinfections - sanitary supervision and withdrawal from use of contaminated products; in case of rabies, the destruction of the source of infection, i.e., stray dogs and other animals; with poliomyelitis - general vaccination of children, etc.

Bibliography

I.G. Bulkin "Infectious Diseases".

IN AND. Pokrovsky "Prevention of infectious diseases"

N.R. Paleeva "Directory of a nurse"

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Infectious skin diseases

The largest organ of the human body, which is a barrier between the external world and the internal environment of the human body, is the skin.

The skin has the following functions:

protects internal organs from various kinds of damage;
acts as a barrier, protecting the body from foreign organisms;
participates in metabolic processes;
endocrine (enzyme production);
tactile organ.

It turns out that the skin plays no less important role than the heart, liver, kidneys and other organs.

A large group of infectious diseases are mycoses - fungus.

Remember! Some of the fungi that cause these diseases are transmitted only from person to person. Microsporia can also be transmitted from animal to human.

Another type of fungal disease is Candida fungi. They affect mucous membranes, skin, internal organs. They penetrate into the body with a drop in immune defense, disorders in the endocrine system, frequent stress, prolonged use of antibiotics.

Candidiasis can be:

Superficial - damage to nails, mucous membranes, skin. The lesions can be located in the axillary and interdigital folds. The mucous membranes of the mouth (thrush), male and female genitals may be affected.
Visceral - damage to internal organs. Penetration into the respiratory tract, digestive organs, nervous system.
Chronic generalized. Often genetically determined. In most cases, in patients with disruption of the endocrine glands.

The disease develops in children with weak immunity, manifested in the form of thrush, lip lesions, thickening of the nail plates, and skin rashes. The lungs and small intestine may be affected.

Felon

This is an infectious purulent inflammation of the tissues of the finger. In most cases, the arms are affected, the legs are less common. The impetus for the development of the disease is a finger injury. Depending on the stage, the doctor chooses the method of treatment. With a purulent formation on the finger, there is only one way out - an operation.

Important! Bacteria can enter any cut, crack, splinter injury, etc. If the wound is not treated, they begin to multiply, provoking purulent inflammation (usually in people with weakened immunity). Suppuration appears and spreads quickly.

Symptoms include shooting or bursting pain in the affected area, swelling, redness of this area, and impaired motor functions of the finger.

Panaritium is skin, periungual, subungual, subcutaneous, bone, articular, osteoarticular, tendon.

Viral disease. The causative agent is the human papillomavirus. When it manifests itself on the mucous membranes, warts appear - warty formations.

The virus can dormant in the human body for a long time. It is transmitted through any kind of sexual contact between a sick person and an infected person (oral, anal, classic sex). Transmission is possible through the use of personal hygiene items of the patient, as well as through the vertical route - during the birth period.

Virus activation occurs with any weakening of the immune defense. The growths form on the genitals, pubis, thighs, around and inside the anus, inside the urethra.

Throat infections

The throat can be affected by various pathogens: fungi, viruses, bacteria. Transmission occurs from a sick person or animal to a healthy one. The routes of transmission are standard: airborne droplets, through mosquitoes, ticks, etc., from sick animals, through contaminated food, water.

Angina

It is an acute infectious disease in which the tonsils and lymph nodes are affected. Develops with reduced immunity, hypothermia. Refers to seasonal diseases (autumn, spring).

Typical signs:

feeling unwell, difficulty swallowing due to sore throat;
high fever, headache, chills;
the tonsils are reddened (depending on the type of sore throat, various kinds of plaque on the tonsils can be noted).

Without timely treatment, it can turn into more complicated forms, cause health problems.

Remember! Good preventive measures will be hardening of the body, strengthening immunity, clothing correctly selected for the season (so as not to overheat and not overcooled), healthy teeth (carious teeth are a source of infection).

Flu

Refers to infectious diseases transmitted by airborne droplets. It affects children and adults, regardless of the season. It is easily transmitted from a sick person to a healthy one. It is located on the mucous membranes of the nose, mouth, pharynx, stands out when talking, coughing, sneezing. Caused by several types of viruses.

How does it manifest:

chills, fever;
headache, body aches;
loss of appetite, drowsiness, feeling unwell, irritability;
reddened eyes, hot skin;
immediately with an increase in temperature or a little later, a runny nose, dry mouth, dry cough appear.

The temperature drops after 3-5 days, the patient is on the mend. It can be complicated by pneumonia, otitis media, heart, kidney, liver damage.

It is necessary to support the body by playing sports, adding vitamins to the diet, and proper nutrition.

Important! For the purpose of prevention, the population is vaccinated. It should be carried out at least a month before the outbreak of the epidemic.

Tonsillitis

It occurs due to the penetration of a bacterial or viral infection into the body. It is characterized by the defeat of one or more tonsils. With a prolonged attack of infections on the lymphoid tissue of the tonsils and the absence of treatment, the infection spreads throughout the body. The main symptom is a sore throat.

Transmission of a virus or bacteria can occur from the external environment (through the air or through food), and self-infection pathways are possible (sinusitis, carious teeth, ethmoiditis).

The disease can occur in an acute form and be called "angina". May be chronic. It passes into this phase after suffering a sore throat, scarlet fever, measles and other infectious diseases.

The main causative agent of the disease is group A streptococcus.In a smaller number of cases of the disease, viruses and streptococci of other groups become pathogens, even less often - fungi and chlamydia.

Infectious diseases in children

These include the diseases of an infectious nature that are most often recorded in childhood, easily transmitted from a sick child to a healthy one and can be epidemic.

Traditionally, childhood infections include:

rubella, chickenpox, measles, mumps, scarlet fever;
whooping cough, polio, hemophilic infection;
pneumococcal and meningococcal infections, acute intestinal and respiratory diseases (flu, tonsillitis, etc.), hepatitis A.

Remember! Infection is what a child can get infected by contact with a patient with pronounced or latent symptoms of the disease. Antibodies transmitted from the mother protect babies from some infections up to one year old.

Key points a parent should keep in mind:

general strengthening of the body's defenses: hygiene, hardening, long walks in the fresh air, proper nutrition;
timely visit to a doctor at the first signs of illness;
vaccination, the abandonment of which creates a layer of easily infectious children, capable of bringing the prevalence of the disease to the size of epidemics.

The list of infectious diseases is quite extensive, as is the number of different pathogens. To avoid infection, it is enough to adhere to standard recommendations, take care of your health, consult a doctor if you feel unwell.

Domestic and field mice, rats, hares, weasels, squirrels and other types of rodents are the reservoir and source of the causative agent of diseases transmitted to humans. Among these diseases are ersiniosis, rat bite disease, tularemia, endemic typhus, leptospirosis, lymphocytic choriomeningitis, sporotrichosis, histoplasmosis, etc.

Of great importance are pathogens such as blood-sucking arthropods (mosquitoes, ticks, mosquitoes, etc.), of which some serve as carriers, and others as a reservoir of pathogens, since the pathogenic agent is transmitted from generation to generation transovarially. Finally, laboratory animals (rabbits, guinea pigs, rats, hamsters, mice, etc.), from which the causative agents of various zoonoses are isolated, are another source of the causative agent of infection for humans.

A person can become infected with diseases in the following ways:

Direct contact with domestic or wild animals, sick or microorganisms;

Processing of corpses, carcasses, blood, skins, wool, etc., obtained from sick animals;

Contact with objects infected with sick animals;

Consumption of food obtained from sick animals, for example, meat and meat products (sausages, smoked meats, canned food, etc.), milk and dairy products (butter, cheese, whey, etc.), fish, especially smoked or salted , or uncooked, caviar, raw eggs, cakes made with raw eggs or milk, ice cream, etc.

In animals, the disease can occur with clinical manifestations, which allows you to take the necessary precautions when working with them, or in latent and inapparent forms, which is much more dangerous from an epidemiological point of view. Animals with latent or inapparent disease appear to be clinically healthy, but they spread disease viruses in the environment through food (milk), excreta (urine and feces), membranes and fluids. This leads to human infection, regardless of whether they are farm animals or pets.

Often, diseases occurring in animals inapparently manifest themselves in humans in a severe clinical form, therefore, in many cases, an animal's disease is detected after a person has become ill. Many examples can show that a person serves as an "indicator" for detecting inapparent infections in animals.

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(Source: Dictionary of Microbiology Terms)

- patogenai statusas T sritis ekologija ir aplinkotyra apibrėžtis Organizmai (virusai, bakterijos, grybai ir kt.), sukeliantys žmogaus ir gyvūnų ligas. atitikmenys: angl. causative organisms; pathogen organisms; pathogenic organisms vok. ... ... Ekologijos terminų aiškinamasis žodynas

PATIENT (DISEASE); PATHOGEN - English pathogen; pathogenic agent German Anreger; Erreger; Krankheitserreger; Krankheitserreger; Pathogen French agent pathogène see\u003e ... Phytopathological dictionary-reference

African swine fever: symptoms and causative agent - African swine fever (Latin Pestis africana suum), African fever, East African plague, Montgomery's disease is a highly contagious viral disease of pigs characterized by fever, cyanosis of the skin (bluish coloration) and extensive ... ... Encyclopedia of Newsmakers

Causative agent, causative agent, husband. (specialist.). 1. Beginning giving rise to some kind of process. Yeast is a fermentation agent. The causative agent of the disease (mainly bacteria). 2. A special electromagnetic device (radio). Dictionary Ushakov. D.N. Ushakov. 1935 ... ... Ushakov's Explanatory Dictionary

Human diseases transmitted through animals - Diseases that are transmitted from animals to humans are called zooanthroponosis. Zooanthroponoses, anthropozoonoses are a group of infectious and invasive diseases common in animals and humans. Zooanthroponoses include about 100 diseases ... ... Encyclopedia of Newsmakers

Infectious diseases

Among the many diseases that a person is susceptible to, there is a special group of diseases that are considered to be contagious, or infectious.

Infectious diseases are diseases caused by a live pathogen that have the ability to be transmitted from a sick person to a healthy one, causing epidemics. Such pathogens, as a rule, are microorganisms - organisms that cannot be seen with the naked eye, but only with the help of more or less powerful microscopes.

But not all microorganisms pose a threat to human health. Some microbes can be found inside the human body without causing disease and even aiding life processes such as digestion. According to this, all microbes on the globe are divided into three large groups of pathogenic microorganisms, that is, those that cause diseases can be:

Bacteria (cholera, sepsis, tuberculosis);

Viruses (influenza, hepatitis, HIV);

Fungi (skin mycoses);

The simplest animals (dysentery, malaria)

Bacteria

Bacteria are unicellular prenuclear organisms. There are more than three thousand species of them on Earth. They are microscopic in size (0.2 to 1 micron). The morphology of bacteria is quite diverse, according to this they are classified in a certain way according to their shape and ability to form groups. So, the following forms of bacteria are distinguished.

1. Monocoque. No groupings are formed. They have a spherical cell shape. Among them, truly pathogenic forms are rarely found. The most common representatives of monococcus are orange micrococcus (Micrococcus aurentiacum) and white micrococcus (Micrococcus album), which, when multiply, form orange and white spots on food.

2. Diplococci. There are several varieties. More often there is a combination of two bacterial cells of a spherical shape, covered with a mucous membrane. This is the form of nitrogen-fixing brown azotobacter (Azotobacter croococcum), the causative agent of pneumonia (Dyplococcus pneumonius). There are also combinations of two cells that look like coffee beans. These include the causative agents of gonorrhea (Neiseria honored) and meningitis (Neiseria miningitidis).

3. Streptococci. The cells, spherical in shape, form long chains. Among them, there are both non-pathogenic, for example, those that cause sour milk (Streptococcus lactis), and pathogenic, which cause diseases of angina, scarlet fever, rheumatic heart disease. Their characteristic feature is that in the process of their vital activity they secrete c-reactive protein, which has hemolytic properties, i.e. those that destroy hemoglobin (Streptococcus piogenes).

4. Sarcinas. Several globular bacterial cells form small groups. The characteristic feature of this type of bacteria is the formation of spores and extremely fast reproduction. Representatives include Sarcina flava, which forms yellow spots on food, and Sarcina urea, which decomposes urine.

5. Staphylococci. There are also pathogenic and non-pathogenic forms. For example, Staphylococcus aureus (Staphylococcus aureus) forms golden colonies in the culture medium and does not pose any direct threat to human health. At the same time, there are a number of extremely dangerous staphylococci that cause severe inflammation: scarlet fever, sepsis. A colony of staphylococci is always a large collection of spherical cells. A characteristic feature of this group is its strong mutagenicity - the ability to form new forms.

6. Cocobacteria. A group of bacteria is extremely common in the environment. The cells are very small rods that are sometimes difficult to distinguish from micrococci. So, Pseudomonas lives in water and soil, which plays an important role as decomposers. In the gastrointestinal tract of humans and animals, there is a conditionally pathogenic E. coli (Esherichia Coli), which, on the one hand, helps digestion, but, on the other, some of its forms can cause cholecystitis, pancreatitis. Among the causative agents of diseases, Salmonela tiphi can be distinguished, which causes typhoid, Proteus vulgaris is an anaerobe, which is the cause of a painful state of cavities (for example, maxillary).

7. Bacilli. Evolutionarily more advanced forms of bacteria, they are cylindrical and form spores. Also, can always use nutrients from the environment. The bacillary form is Bacilus subtilis - a hay bacillus that multiplies rapidly in warm tea, Bacilus turingiensis - a bacterium that is of great importance for the development of environmentally friendly insecticides. It secretes a protein substance that causes paralysis of the intestinal apparatus of insects.

9. Streptobacillus. Just like streptococci, they form long chains of their cells. There are pathogenic streptobacilli. Thus, Streptobacilus antracis is the causative agent of anthrax.

10. Clostridia. They have a fusiform shape, they are characterized by an anaerobic breathing method. That is why most clostridia are pathogenic microorganisms. Clostridium tetani - the causative agent of tetanus, Clostridium botulinum - causes a severe violation of the digestive system - botulism, Clostridium septicum - the causative agent of gas gangrene. Clostridium perfringens is an indicator of faecal soil contamination. While living in the body, it enriches it for enzymes, but in case of diabetes, it can cause gangrene.

11. Vibrios. Refers to shapes that are sometimes called tortuous. They are sticks bent by less than a quarter of a circle, trembling slightly. A typical representative of vibrios is the causative agent of cholera Vibrio cholera, which sometimes forms blue colonies. Its peculiarity is that it is the only one that tolerates an alkaline environment (pH greater than 7).

14. Mycoplasmas. Interesting bacteria, because they do not have a cell membrane. ) X can be viewed as a transitional form between viruses and cellular life forms. A characteristic feature is that they are completely incapable of living outside the host cell. Basically, mycoplasmas are represented by pathogens of diseases of plants and cattle.

In addition to the classification of bacteria by cell shape, a very important systematic feature is their color. All methods of classification of bacteria by color are based on their unequal internal chemical composition. The most generalized classification method is Gram stain. This method allows you to divide the entire huge number of bacterial organisms into two groups: gram-positive (turn purple after staining) and gram-negative (turn red after staining).

The practical importance of such a taxonomy lies in the unequal sensitivity of gram-positive and gram-negative bacteria to antibiotics. Thus, gram-positive bacteria are more sensitive to antibiotics of the penicillin series, and gram-negative bacteria to antibiotics of the gentomycin and streptomycin series. This determines the methods of treatment of infectious diseases.

There is an interesting feature of the spread of bacteria of various forms in the human body. By the percentage ratio between the types of microorganisms, you can determine the predisposition to a particular disease, prevent complications, and start treatment on time. A microflora sample is taken from the oral cavity, and its analysis can be easily done even at home with a microscope.

So, if streptococci and staphylococci dominate, this indicates respiratory diseases. If rod-shaped forms (bacilli, streptobacilli, etc.) prevail, diseases are possible gastric tract... The appearance of diplococci is a sign of a disease of the genital organs, candida (branched chains of globular bacteria) is an indicator of dysbiosis, possibly thrush, stomatitis develops. Spirochetes are satellites of the inflammatory process in the oral cavity. If all bacteria are in approximately the same amount, there is no reason to worry.

Viruses

The second group of common causative agents of human diseases are viruses. A virus is an autonomous genetic unit capable of reproduction (reduplication) only in the host cell. Viruses can be thought of as substances outside the cell. But, getting into the host's organism, they begin to behave like living beings.

The structure of the virus is quite simple. It consists of a piece of nucleic acid (DNA or RNA) and protein molecules that act as a shell (Fig. 49). The protein coat is enzymatically active, it ensures the attachment of the virus to the host cell. Viruses are specific, they infect not only a specific species of animals, plants or humans, but also certain host cells, so the poliomyelitis virus infects only nerve cells and does not harm others.

Depending on the type of nucleic acid, DNA genomic and RNA genomic viruses are distinguished. DNA genomic pathogens include hepatitis B, chickenpox, and shingles. RNA genomic viruses cause influenza A, B, C, measles and other diseases. A special group of viruses is made up of the so-called retroviruses, a representative of which is the well-known HIV - human immunodeficiency virus. HIV infects cells that are responsible for immunity. In case of infection, the serious illness AIDS occurs.

The mechanism of action of viruses is that, getting into the body, they adsorptively penetrate the host cell. Here the transition from an inert (crystalline) state to an active one takes place. Then the virus sheds its envelope, releasing a piece of nucleic acid, which is incorporated into the genetic apparatus of the cell. The synthesis of the components of the virus (nucleic acids, proteins) takes place. The newly formed particles rupture the cell and go outside, damaging nearby cells.

The vital activity of some viruses is quite specific. They can enter the human body, integrate their nucleic acid into the DNA or RNA of the host cell. But, remaining in the cell, they are in a kind of symbiosis (the phenomenon of virogeny) and do not manifest themselves in any way. Thus, vital activity is characteristic of retroviruses.

It is known that the main reason cancerous tumors lies in the action of just such viruses. The newly formed gene, which did not manifest itself for a long time, during nervous stress, exposure to radiation, carcinogenic substances begins to function actively and forces the cell to synthesize stimulants of mitotic division. The resulting excess protein leads to the formation of cancerous tumors.

Among other features of the vital activity of many forms of viruses (for example, the causative agent of influenza), the so-called antigenic drift should be noted - mutations that occur in the pathogen every 2-3 years. The content of this process consists in replacing some part of the gene. The gene is completely replaced after 8-11 years. The significance of this process lies in countering specific immunity. It is interesting that one virus, once it enters the human body, protects it from other viruses. This phenomenon is known as virus interference.

A special group of microorganisms are phages - bacteria viruses. They are built more complexly, under an electron microscope you can see that they have the shape of a comma or a club with dimensions of 5-6 nm. They consist of a head, a rod, inside which there are special contractile proteins, and several processes.

Phage infects both pathogenic and non-pathogenic bacteria, so it was thought that it could be used to treat infectious diseases. But it turned out that inside the human body, the phage loses its activity. Therefore, it can only be used to diagnose bacterial infections.

Mushrooms

The body of the fungus (mycelium) can consist of one highly branched cell, or many. Urea is the main waste product of fungi. Mushrooms reproduce extremely intensively, as a rule, by peculiar spores or budding.

Protozoa and worms

Another group of pathogens of infectious diseases are protozoa and worms.

The simplest animals that cause diseases include dysentery amoeba, coccidia, sporozoans like that. The body of the simplest animals consists of only one cell, which performs all the functions of a whole organism. So, a dysentery amoeba resembles a piece of protoplasm, constantly changes its shape, and can actively move. Once in the human body, it causes a serious illness of the digestive system - dysentery.

The cause of the disease is always the penetration of the pathogen into the human body if hygiene rules are not followed, violation of cooking technology, contact with patients, etc.

There are five main kingdoms of living nature, representatives of which have been subjected to careful study over many centuries. It:

animals;
plants;
mushrooms;
bacteria, or prokaryotes;
viruses.

If animals, plants and fungi were known to people from the very times of primordial creation, then people began to study viruses and bacteria relatively recently. These organisms are too small in size to be able to study them with the naked eye. That is why they have been hidden from the watchful eye of humanity for so long.

It is known that they play not only a positive role. So we will try to understand the question of which bacteria are the causative agents of what diseases, and how these creatures are generally arranged and live.

Who are prokaryotes?

All living beings on our planet are united by a common structure - they consist of cells. True, part of everything is from one, the other part is multicellular. If we talk about multicellular animals, then everything is the same. Each such organism has a formed nucleus in its cells. But when it comes to unicellular organisms, there is no such unity, since they are divided into eukaryotes and prokaryotes.

Eukaryotes include all living things whose cells have hereditary material fixed in the nucleus. To prokaryotes - such unicellular organisms in which the DNA is freely distributed, not limited by the nuclear envelope, and therefore does not have a nucleus as a whole. It is customary to refer to these creatures:

blue-green algae;
cyanobacteria;
archaebacteria;
bacteria.

Initially, only such organisms lived on the planet. But gradually evolution came to the emergence of eukaryotic cells inside which prokaryotic cells remained. Then, having united together and entering into a symbiotic relationship, they became a wonderful, strong, resistant to environmental conditions organism, ready for self-reproduction and increase in numbers, evolution.

The proof of this theory is such non-nuclear cell organelles of multicellular organisms, such as mitochondria and plastids (chloroplasts, chromoplasts, leukoplasts).

But, unfortunately, many of the prokaryotic cells are not as harmless to plants, animals and people as those that remained to live inside them. They received the modern name bacteria, or microbes, and began to live an independent life, causing a lot of trouble for highly organized beings.

Many diseases associated with bacteria and their vital activity are known. And not only in humans, but also in representatives of all others

A brief outline of the history of the discovery

Bacteria have been around for over 3.5 billion years. During this time, nothing has changed in their structure. The only thing that has become new in their life is their fame for humans.

How did the discovery of these organisms come about? Let's consider in stages.

Even the ancient Greek scientist Aristotle said that there are creatures invisible to the eye that live on everything around, including on humans. They can cause disease.
1546 - Italian physician Girolamo Frakostoro suggested that human diseases are caused by the smallest organisms, microbes. However, he could not prove it and remained unheard.
1676 - Antonio van Leeuwenhoek studied a cut of a cork tree under a microscope invented by his own hand (the first microscope of his production was very large and resembled a collection of several differently positioned mirrors, it gave an increase of more than a hundred times). As a result, he was able to see the cells that make up the tree bark. And also, looking at a drop of water, he considered many of the smallest organisms that lived in this drop. These were the bacteria, which he gave the name "animalculi".
1840 - German doctor Jacob Henle puts forward a completely correct hypothesis about the action of pathogens on humans, that is, that bacteria are the causative agents of diseases.
1862 - French chemist Louis Pasteur, as a result of multiple experiments, proved the presence of microorganisms in all environments of life, objects, organisms. Thus, he confirmed Hen-le's hypothesis, and it has already become a theory called the "Microbial Theory of Diseases". The scientist was awarded the Nobel Prize for his work.
1877 - Robert Koch introduces the method of staining bacterial cultures.
1884 - Hans Gram, physician. It is he who is credited with dividing these creatures into gram-positive and gram-negative, depending on the reaction to the type of dye.
1880 - Karg Ebert identified the cause of typhoid fever - the action of the rod-shaped bacteria.
1882 - Robert Koch isolates the tubercle bacillus.
1897 - Japanese physician Kiy-si Shiga discovered the cause of dysentery
1897 - Bernhard Bang established the fact that there are bacteria that cause animal diseases that cause miscarriages in them.

Thus, the development of knowledge about bacteria and diseases caused by them was gaining momentum. And today more than 10 thousand different representatives of prokaryotes have already been described. However, scientists predict that there are more than a million species of them in the world.

Prokaryotic sciences

Bacteria as causative agents of infectious diseases have always been interesting to science, because knowledge about them allows solving many health problems not only of humans, but also of animals and plants. Therefore, several sciences have formed that are studying this issue.

Microbiology is a general science that studies all microscopic organisms, including bacteria.
Bacteriology is a science that studies microbes, bacteria, their diversity, lifestyle, distribution and influence on the world around them.
Sanitary Microbiology - studies preventive measures for human development.
Veterinary microbiology - investigates bacteria-causative agents of infectious diseases in animals, methods of elimination, treatment, prevention of infection.
Medical Microbiology - examines the influence of bacteria on the life of all living things from the point of view of medicine.

In addition to bacterial cells, there are also unicellular protozoa organisms, causative agents of diseases in humans, animals and plants. For example, amoebas, malaria plasmodia, trypanosomes, and so on. They are also objects of study in medical microbiology.

What are bacteria?

There are two bases for the classification of bacterial cells. The first is built on the principle of separating microbes of various cell shapes. So, on this basis, there are:

Cocci, or organisms. This also includes several varieties: diplococci, streptococci, staphylococci, micrococci, sarcins, tetracocci. The sizes of such representatives do not exceed 1 micron. It is to this group that the majority of those who are called "causative agents of human diseases" belong.
Rods, or rod-shaped bacteria. Varieties in the shape of the ends of the cells: regular, pointed, clavate, vibrios, trimmed, rounded, chained. All these bacteria are pathogens. What diseases? Almost all infectious, known to man today.
Twisted organisms. Subdivided into spirillus and spirochetes. Thin twisted spiral structures, some of which are pathogenic microbes, and the other are representatives of the normal intestinal microflora of animals and humans.
Branching bacteria - basically resemble rod-shaped forms, but at the end they have branching of varying degrees. These include bifidobacteria, which play a positive role in human life.

Another classification of bacterial cells is based on modern indicators: RNA in structure, biochemical and morphological properties, relation to staining, and so on. On these grounds, all bacteria can be divided into 23 types, each of which includes several classes, genera and species.

You can also classify microorganisms by the way they eat, by the type of respiration, by their habitat, and so on.

Human use of bacteria

People have learned to use microorganisms since ancient times. On their part, it was, of course, not purposeful use, but simply a profitable acquisition from nature. So, for example, alcoholic beverages were produced, fermentation processes took place.

With the passage of time and the disclosure of the mechanisms of life of these tiny creatures, man has learned to more fully apply them in his needs. There are several branches of the economy with which biology is closely intertwined. The bacteria are used:

In the food industry: baking of confectionery and bread, winemaking, lactic acid products and so on.
Chemical synthesis: bacteria produce amino acids, organic acids, proteins, vitamins, lipids, antibiotics, enzymes, pigments, nucleic acids, sugars and so on.
Medicine: drugs that restore the microflora of the internal environment of the body, antibiotics, and so on.
Agriculture: preparations for plant growth and treatment of animals, strains of bacteria that increase yields, milk yield and egg production, and so on.
Ecology: oil-decomposing microorganisms, processing organic and inorganic residues, cleaning the environment.

However, in addition to the positive effects of using bacteria, people cannot get rid of the negative ones. After all, bacteria are the causative agents of what human diseases? The most difficult, dangerous and sometimes deadly. Therefore, their role in nature and human life is dual.

Pathogenic microbes: general characteristics

Pathogenic microbes include those that are capable of causing damage to tissues and internal organ systems in humans and animals. In terms of their external and internal structure, they are no different from beneficial bacteria: a single-celled structure covered with a dense membrane (cell wall), outside is clothed in a mucus capsule that protects from digestion inside the host and from drying out. The genetic material is distributed within the cell as a chain of DNA molecules. Under unfavorable conditions, they are able to form spores - to fall into a state of stupor, in which the processes of vital activity stop until the resumption of favorable conditions.

Bacteria are the causative agents of what diseases of living beings? Those that are easily transmitted by airborne droplets, by direct contact or by contact with open mucous areas of the skin. This means that disease-causing organisms can be called weapons of mass destruction. After all, it is they who are capable of causing whole epidemics, pandemics, epizootics, epiphytotics, and so on. That is, diseases that cover entire countries, affecting both plants (epiphytoties), and animals (epizootics), and humans (epidemics).

Unfortunately, not all types of such creatures have been fully studied by humans yet. Therefore, there is no guarantee that at any moment there will be no infection, unknown to people. This places an even greater responsibility on microbiologists, medical researchers and virologists.

What diseases are caused by bacteria?

There are many such diseases. At the same time, it is impossible to single out only some common ones. After all, bacteria are capable of infecting not only animals, but also Therefore, all diseases that they cause are usually divided into several groups.

Anthroponous infections are those that are characteristic only for humans, and infection is possible strictly between them (pathogens of human diseases). Examples of diseases: typhoid, cholera, smallpox, measles, dysentery, diphtheria and others.
Zoonotic diseases are infections that animals suffer from and which they carry in themselves, but in any way they can infect humans. So, for example, with the bites of insects or other animals, when animals come into contact with the skin and human respiratory tract, bacterial spores are transmitted. Diseases: glanders, anthrax, plague, tularemia, rabies, foot and mouth disease.
Epiphytic infections are plant diseases caused by bacteria. These include rot, spots, tumors, burns, gommosis and other bacteriosis.

Consider human diseases caused by bacteria. Those that are the most common. They have brought many troubles and troubles to people in the past and present.

Human bacteria

Human diseases caused by bacteria have always caused a lot of harm and damage to human health. The most common and dangerous ones are the following:

Plague is a terrible word for the inhabitants of the Middle Ages and the Renaissance. This disease has claimed thousands of lives. Earlier, getting sick with the plague was tantamount to death, until they came up with a method of vaccination and a cure for this terrible infectious disease. Now this disease occurs in some tropical countries and is strictly zoonotic in nature.
Erysipelas is a disease of animals, mainly pigs, chickens, lambs, horses. Transmitted to humans. Its names are called Erysipelothrix insidiosa. The fight against the disease is simple, these pathogens are afraid of direct sunlight, high temperatures and alkalis. Currently, the disease is not very common. The occurrence of foci depends on the conditions of keeping the animals.
Diphtheria. A dangerous disease of the upper respiratory tract, gives a strong complication to the heart. Today it is quite rare, since vaccination is carried out in the early stages of a child's development.
Dysentery. This disease is caused by bacteria called Shigella. The source of infection is sick people who are able to transmit the infection by household, water or contact (through the mouth). Children are most susceptible to the disease. You can get sick with dysentery several times, since immunity to the disease is formed only temporarily.
Tularemia is caused by the bacterium Francisella tularensis. A very tenacious infection, resistant to temperatures, environmental conditions. Treatment is complex, not fully developed.
Tuberculosis - caused by Koch's bacillus. A complex disease that affects the lungs and other organs. Healing systems have been developed and are widely practiced, but it has not yet been possible to completely eradicate the disease.
Whooping cough is an infection caused by the bacteria Bordetella pertussis. It is characterized by the appearance of the strongest coughing attacks. Vaccination in early childhood.
Syphilis is a very common sexually transmitted infection. It is caused by the pathogen spirochete trypanosome. It affects the genitals, eyes, skin, central nervous system, bones and joints. Antibiotic treatment is known to medicine.
Gonorrhea, like syphilis, is a 21st century disease. Sexual transmission, antibiotic treatment. It is caused by bacteria - gonococci.
Tetanus - caused by the bacillus Clostridium tetani, which releases the strongest toxins into the human body. This leads to severe cramps and uncontrollable muscle contractions.

Of course, there are other bacteria and human diseases. But the listed are the most common and serious ones.

Animal germs

The most common animal diseases that are caused by bacteria include:

botulism;
tetanus;
pasteurellosis;
colibacillosis;
bubonic plague;
melioidosis;
yersiniosis;
vibriosis;
actinomycosis;
anthrax;
foot and mouth disease.

All of them are caused by certain bacteria. Diseases for the most part can be transmitted to people, therefore, they are extremely dangerous and serious. The main measures to prevent the spread of such diseases are keeping animals clean, taking care of them, limiting contact with sick people.

Plant microbes

Among the harmful microbes that infect root systems and shoots of plants and thereby cause serious damage to agriculture, the most common are the following:

Mycobacteriaceae;
Pseudomonadaceae;
Bacteriaceae.

Plant diseases caused by bacteria cause rotting and death of the following parts of cultivated plants:

roots;
leaves;
stems;
fruits;
inflorescences;
root crops.

That is, the entire plant can be affected by the pathogen. Most often, agricultural crops such as potatoes, cabbage, corn, wheat, onions, tomatoes, makhorka, grapes, various fruit trees and other fruits, vegetables and cereals are affected.

The main diseases include the following:

bacterioses;
bacterial spotting;
rot;
hazelnut;
basal bacteriosis;
bacterial burn;
ring rot;
black leg;
gommosis;
striped bacteriosis;
black bacteriosis and others.

Currently, botanists and agricultural microbiologists are actively working to find plant protection products against these scourges.

Back forward

Attention! The slide preview is used for informational purposes only and may not represent all the presentation options. If you are interested in this work, please download the full version.

Goal:

to acquaint students with information about the main human bacterial diseases,
continue the formation of the concept and rules of a healthy lifestyle

Tasks:

Find out how pathogenic bacteria enter the human body
What are the most dangerous diseases caused by bacteria
What are the main measures to combat disease-causing bacteria
How to protect your body from harmful bacteria
Equipment: media projector, ppt presentation

Plan

1. Human bacterial diseases

2. Botulism - the causative agent, routes of infection, control measures

3. Dysentery - the causative agent, routes of infection, control measures

4. Tetanus - the causative agent, the possibility of infection, preventive control measures

5. Anthrax - the causative agent of the disease, ways of infection and preventive measures

6.Tuberculosis - the causative agent of the disease, ways of infection, preventive measures

8. Cholera - the causative agent of the disease, ways of infection, control measures

9. Plague is the causative agent of the disease, possible routes of infection, control measures

1. Human bacterial diseases (slide 2)

The number of human bacterial diseases is enormous. To date, diseases caused by bacteria are the most dangerous, since they can not only worsen the quality of human life, but also lead to death. Therefore, we need to know not only the causative agents and symptoms of human bacterial diseases, but also the possible causes of these diseases and possible measures to combat them. Bacterial diseases include: plague, cholera, anthrax, tuberculosis, botulism, tetanus, tonsillitis, meningitis, diphtheria, dysentery, whooping cough, scarlet fever, gastritis, stomach ulcers, and the list goes on and on.

2. Botulism - causative agent, routes of infection, control measures (slides 3-4)

The causative agent is Clostridium botulism, it is widespread in nature with a permanent habitat in the soil. It can also be found in manure, fruits, vegetables, fish, excrement of warm-blooded animals. Able to form spores that are highly resistant to chemical and physical factors. The spores are able to withstand boiling for 5 hours at 120 degrees Celsius. In an environment with a low oxygen content, they multiply rapidly and form a dangerous toxin (poison). Botulinum toxin is one of the most famous and powerful poisons. The pathogen itself does not cause disease in humans, only its toxin is dangerous. For the occurrence of poisoning, it is necessary to multiply the pathogen with the accumulation of botulinum toxin in the body.

It develops as a result of ingestion of food products: ham, sausages, salted fish, as well as canned vegetables, fruits, and especially mushrooms. In recent years, cases of botulism in Russia have been associated with homemade canned foods. The safety of "jars" sometimes cannot be established by eye, botulinum toxin does not lead to a change in the color, smell and taste of food. Bloated cans must be destroyed.

Botulism is a severe toxic-infectious disease that affects the central nervous system, mainly the medulla oblongata and spinal cord. Botulinum toxin is absorbed into the bloodstream in the intestines and selectively affects different parts of the nervous system. There is a paralysis of the respiratory muscles, muscles of the larynx, pharynx. Cases of fatal poisoning have been reported.

Poisoning develops very quickly, there is nausea, vomiting, cramping abdominal pain, loose stools. At the first sign of poisoning, immediately consult a doctor.

In order not to become infected with botulism, it is necessary: \u200b\u200bto strictly observe the rules of personal hygiene; for canning, use only vegetables and fruits, mushrooms thoroughly cleaned from dirt. Jars and lids for canning should be washed, scalded with boiling water, and dried. Vegetables, and especially mushrooms, rolled up in jars, cooked at home are strictly prohibited from buying from strangers.

3. Dysentery - causative agent, routes of infection, control measures (slides 5-6)

Dysentery is an infectious disease caused by the bacterium dysentery bacillus.

Infection occurs when the pathogen enters the body through the mouth with food, water, or through dirty hands. Flies can be carriers of dysentery sticks. Only people get sick with dysentery. The source of infection can be a sick person. The infection can spread very quickly.

Dysentery is a disease characterized by increased stool frequency, an admixture of mucus and blood in the stool, cramping abdominal pain, an increase in body temperature to 39 degrees or more. Stool frequency can be up to 15-25 times a day or more. The disease is especially difficult in children. the child's body dehydrates faster than adults. Earlier, when there were no antibiotics for dysentery, people died.

Treatment of dysentery is aimed at destroying the pathogen and it is carried out in a hospital with an infectious profile.

Preventive measures: regular and thorough washing of hands after using the toilet, walking and before eating, raw vegetables and fruits, get rid of flies indoors, and avoid contact with food. It is not for nothing that dysentery is called "the disease of dirty hands." Currently, you can get a prophylactic vaccination against dysentery.

4. Tetanus - causative agent, possibility of infection, preventive measures (slides 7-8)

Tetanus bacillus is a microscopic bacterium that lives in the gastrointestinal tract of herbivores. Tetanus is an acute infectious disease in humans, as a result of which the nervous system is affected, the innervation of skeletal muscles is disrupted. Together with the fecal masses of sick animals, a huge number of pathogen spores are released. Spores are very resistant to environmental factors, they can maintain their ability to live for years, being in a state of spore with the soil.

The disease begins acutely. The disease is accompanied by cramps of skeletal muscles: muscles of the body, limbs, facial muscles, muscles of the pharynx. As a result of the strongest tone and painful condition of the back muscles, the patient's back arches in an arc. The muscle spasm is so severe that bone fractures and their separation from the bones are possible.

The tetanus bacillus enters the human body through wounds, scratches and other damage to the skin. In some regions, tetanus is called Bare Feet Disease, as even a splinter in the foot or a rusty nail can be a gateway to infection.

Preventive measures: Reducing injuries, especially when working with the ground (work with gloves or gloves), get preventive vaccinations, every 10 years

5. Anthrax - the causative agent of the disease, routes of infection, preventive measures (slides 9-10)

Anthrax has been known since ancient times. It is called a malignant carbuncle. The causative agent is a bacterium in the form of a rod, it has the ability to sporulate. It can survive for decades in the soil or in the tanned skin of sick animals. Under favorable conditions, the bacterium passes from the spore into an active state. The causative agent of anthrax was first identified by Robert Koch. Until now, anthrax occurs in the countries of Central Asia, Africa and South America... It got its name because of its distribution in the past in some regions of Siberia. Nowadays it is very rare in Russia.

The source of infection is sick herbivores: sheep, horses, camels, deer, pigs. Excavation work, soil water during heavy rains and floods promote the penetration of bacterial spores into the upper layers of the soil, creating conditions for infecting people and animals. With the disease, the skin is often affected. Diagnosis of the disease is not difficult.

Disease-causing bacteria are released into the external environment with animal urine, saliva, feces, milk and wound secretions. After their death, their organs remain infectious, even their skin, wool and bones. The most common method of infection is contact with sick animals.

With anthrax, exposed areas of the body - hands and face are more often affected. At the site of introduction of the pathogen, first a red spot appears, in its place, over time, a papule of a red-cyanotic color appears, which begins to burn and itch, then a bubble with liquid appears, and it bursts when combing. The resulting ulcer quickly becomes covered with a black scab. Lymph nodes are enlarged. The process is accompanied by symptoms of intoxication.

Disease prevention is carried out in close contact with the veterinary service.

6. Tuberculosis - the causative agent of the disease, routes of infection, preventive measures (slides 11-12)

The causative agent of the disease is the bacterium tubercle bacillus (Koch's sticks). Tuberculosis rods are resistant to environmental factors. They can be stored in water for up to six months. Stable for a long time in the dark and damp. and at high temperatures and illumination by the sun they quickly die. Until the 20th century, tuberculosis was incurable. The main source of infection - a bacillus-releasing agent - is a sick person. The greatest danger is presented by patients with an open form of tuberculosis. The disease often develops in people who abuse alcohol, and tuberculosis is also widespread in people who are in places of detention (prisons, colonies), or recently released. It is transmitted by airborne droplets, intrauterine infection is also possible.

The main organ of the lesion is the lungs. There are signs by which tuberculosis can be suspected - cough, chest pains, and hemoptysis. Tuberculosis is diagnosed with fluorography.

The basis of treatment is the use of anti-tuberculosis drugs. The duration of treatment depends on the severity of the disease. In some cases, they resort to surgery. Earlier, when antibiotics were not known, people died of tuberculosis and called this disease "consumption." Now there is a whole area of \u200b\u200bmedicine dealing with tuberculosis - phthisiology, and its specialists are doctors phthisiatricians.

Prevention of tuberculosis consists in the timely passage of fluorography, giving up bad habits - smoking, especially alcohol, eating right, and leading a healthy lifestyle.

7. Helicobacter pylori - the causative agent of the disease, the possibility of infection, prevention

(slides 13-14)

The bacteria Helicobacter pylori are by far the most common. More than half of the world's population can be considered carriers of this bacterium, which is now the most studied bacterium in the world. It is necessary to know what the main signs of infection with the Helicobacter bacterium look like so that treatment begins in a timely manner. The bacterium lives in the gastrointestinal tract. It feels good in the stomach and is well adapted to the aggressive acidic environment of the stomach.

The exact mechanism of infection is still unknown. There is only an assumption that infection can occur - through dirty hands and contaminated food or water. The disease can be considered familial. Should one of the family members become infected with the bacteria, then all other family members will develop symptoms of the disease.

Signs of illness: problems with stool (either constipation or diarrhea, heartburn, unreasonable nausea or vomiting, bad breath). The disease leads to gastric and duodenal ulcers, gastritis, predisposition to stomach cancer.

Diagnostic methods: gastroscopy with biopsy of the gastric mucosa, stool analysis, blood test for antibodies. There are many diagnostic methods, but none of them can be considered absolutely reliable.

Preventive measures: personal hygiene products should be individual, wash hands before eating, do not smoke, do not abuse alcohol. Vaccination against the bacteria Helicobacter pylori has not yet been created. It is very difficult to create a vaccine that works in the acidic environment of the stomach.

8. Cholera - the causative agent of the disease, routes of infection, control measures (slides 15-16)

The causative agent of cholera is the bacterium Vibrio cholerae. It is found in open water bodies, sewage, and can develop in meat products and milk. According to the World Health Organization, 3-5 million people worldwide fall ill with cholera every year. Highly contagious, cholera kills up to 1.5 million children annually. It has been proven that cholera epidemics occur in countries with a low standard of living. More than 2.5 billion people on Earth do not know what a toilet is, they cannot even wash their hands. Flies are carriers of infection. Cholera is a terrible disease that at one time claimed millions of lives. Vibrio cholerae affects the organs of the gastrointestinal tract, mainly the walls of the small intestine.

Water is the main route of transmission. Infection occurs through infected food, household items, dirty water. The disease begins suddenly. Abdominal pain, frequent acts of defecation, thirst, dry mouth, loss of strength, drop in body temperature, the patient is cold, vomiting appears, blood pressure drops. The result is severe dehydration. The disease is treated with antibiotics.

Preventive measures: do not drink water from unverified sources, observe the rules of personal hygiene, thoroughly wash raw vegetables and fruits.

9. Plague is the causative agent of the disease, possible routes of infection, control measures(slides 17-18)

10. Conclusion(slide 19)

Yes, man is always in danger, he has a lot of invisible enemies who seek to get into the human body. Therefore, we must learn to protect ourselves from them, using the most elementary rules of personal hygiene - wash our hands thoroughly after using the toilet, before eating, after the street, washing vegetables and fruits before eating, following all heat treatment rules when preserving food, fighting insect carriers of bacterial infections and rodents, make preventive vaccinations.

Compliance with these basic life rules will help you maintain health from a young age and for many years to come. After all, it is not bought or sold. Take good care of your health!

INFORMATION SOURCES:

1.http: //diagnos.ru

2.http: //mymedicalportal.net

3.http: //womanadvice.ru.ru

4.www. mikrobak.ru

5.www.provizor.com

6.www.factorpop.ru

7.http: //medicina.ua

8.http: /www.skalpil.ru

9.www.jobsmediciner.ru

10. Photos and pictures - www.yandex.ru

Diseases caused by bacteria. Bacterial diseases. Major human diseases caused by bacteria. Human use of bacteria

What bacteria are the causative agents of diseases of plants, animals and humans

The main types of classifications of diseases

Bacteriological damage to plants

Infectious diseases of animals

Causative agents of human diseases

Infectious respiratory diseases

Mass diseases and ways of localization of infection

What bacteria are the causative agents of diseases? Bacteria and humans

Causative agents of scabies and other diseases

Bacteria that cause dangerous infectious diseases

Mycobacterium tuberculosis

Anti-ulcer infection

Influenza pathogen

Bacteria, their structure

Cell chemistry

How microorganisms multiply. Spore formation

Bacteriological damage to plants

Infectious diseases of animals

Causative agents of human diseases

Gastrointestinal infections

Infectious respiratory diseases

Mass diseases and ways of localization of infection

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