Science does not stand still. A new method for diagnosing tuberculosis is proposed. What problems does it solve and what conclusions can be drawn from it? How to correlate his results with the results of Mantoux? Is there a false positive? Read on to get answers to these questions.

Tuberculosis disease in humans and animals can be caused by any of the group of pathogenic tuberculous mycobacteria, collectively referred to as "tuberculosis bacillus" or mycobacterium tuberculosis, Koch's bacillus (VC).

In total, there are 24 pathogenic and potentially pathogenic for humans and animals species of mycobacteria. The causative agents of TB in humans and animals in different countries are eight types of mycobacteria. Four of them were found in Europe and Russia, namely: M. tuberculosis humanis - "human", M. tuberculosis africanum - "intermediate", M. tuberculosis bovis - "bovine", M. tuberculosis avium - "avian" (names given at the place of first discovery). See " on our website.

Two closely related species of mycobacterium tuberculosis are of epidemic importance in Russia and Europe, namely M. tuberculosis humanis and M. tuberculosis bovis, that is, "human" and "bovine" Laboratories are not strictly aimed at identifying (not at all simple) each type of mycobacterium separately, since the biological coincidence is 99.9% [http://ru.wikipedia.org/wiki/Mycobacterium_tuberculosis ] and the treatment is the same.

Adults after 30-40 years old are almost completely infected (not sick s!) Mycobacterium tuberculosis and sensitized by it (see). An intra-skin test with () or on-skin (Pirke's test) is positive in people infected (not only sick, but also practically healthy!) Mycobacterium tuberculosis with ANY OF EIGHT pathogenic species, that is, capable of causing tuberculosis disease. It is believed that children endure a meeting with a tuberculosis bacillus worse and get sick more often than adults, which is why they are vaccinated.

On the other hand, Dr. med. Sciences M.E. Lozovskaya notes that 50% of children have a turn, i.e. re-infection and its activation occurs with a negative value of . Of 60 children with active pulmonary tuberculosis, it was positive only in 70% of cases. Dr. med. Sciences L.A. Zazimko on his observations comes to the conclusion that a negative result does not exclude the presence of tuberculosis. (St. Petersburg, State Pediatric Medical Academy. April 2011).

In this situation, three questions arise:

1. How safe is the bovine species of Mycobacterium tuberculosis,
2. As far as tuberculin tests can be trusted,
3. Can a sample be replaced?

1. How safe is bovine tuberculosis for humans?

A case called "The Lübeck Tragedy" has long answered the question of the pathogenicity (danger) of the bovine tuberculosis bacillus for humans. In Lübeck 251 healthy child was erroneously vaccinated (per os, i.e. by mouth) with an active culture of bovine mycobacterium (the investigation showed that the culture was poorly stored, the virulent strain was stored in the same incubator, it became infected and activated from it). The children were of the same age, the dose of microbial culture was the same. Fatal outcome was in 29% of children. Among the dead, the primary tuberculosis complex in 85% was in the abdominal cavity and in 15% in the lungs. Of the 174 surviving and long-term observed children, 104 had large calcified foci in the retroperitoneal lymph nodes, 59 in the cervical and 11 in the lungs and intrathoracic lymph nodes.

In Bavaria, in a pastoral region where it was found among cattle, part of the population used fresh milk; when examining a large group of practically healthy schoolchildren, traces of tuberculosis were found in 58% of them. Retroperitoneal and mesenteric lymph nodes were affected in 53% of cases, traces of the primary complex in the lungs and bronchial nodes - in 15% of cases.

Cattle and domestic animals (including cats and dogs) can suffer from tuberculosis; not only bovine, but also human mycobacteria are dangerous for them.

In the south of the United States, on the border with Mexico, the incidence of people with the bovine type of tubercle bacillus has increased to 10%. The reason is the cheese produced in unsanitary conditions, the mycobacterium remains in the cheese for about 300 days. The infection rate of Mexican cattle is very high, about 17% [http://medportal.ru/mednovosti/news/2008/06/05/bovis/].

In the south of Russia for the period 1990-2003. studies were carried out on 148 patients with tuberculosis of the lungs to determine the types of mycobacteria due to the fact that in the flat areas of this republic the number of cattle suffering from tuberculosis increased. These people were investigated 740 sputum samples. It turned out that M. tuberculosis humanis was detected in 75.8% of cases, i.e. "human" stick, and in 24.2% - M. tuberculosis bovis, i.e. "bovine". The authors write: “Our studies have shown that last years there is an accelerated accumulation of Mycobacterium tuberculosis during external environment. They were isolated from all studied material samples (hay, vegetables, water). The statistically significant involvement of sick cattle in the incidence of human tuberculosis is 5-11 times less than the frequency of isolation of M. tuberculosis bovis from the sputum of sick people. (http://www.agroyug.ru/page/item/_id-2864/)

Tuberculous mycobacteria can remain active in the ground for many years, get on plants and infect those who use them, that is, animals and people. Tuberculosis bacillus gets into the ground and the environment not only with sputum and secretions of sick people, but also with feces, urine, saliva of sick animals and their dust, including dogs and cats. Household infection occurs not only with human, but also with bovine type of mycobacteria from a person to a person, from animals, not only by dust and droplets, but also with food. Under unhygienic harvesting conditions, such as in meat, milk, butter, cheese, and their semi-finished products, these mycobacteria can persist for many months. The same can be said about the meat of sick (and infected?) animals. Mycobacteria are not afraid of freezing, their shelf life may increase. According to slaughterhouses in the European part of Russia, livestock is found from 5% to 16%, in Moscow 8.6%. In the eastern part of Russia, VV Ivanov (Krasnoyarsk) believes that at present M. tuberculosis bovis is the most common causative agent of tuberculosis in humans.

It is known that the "human" type of tuberculosis bacillus (aerob) often causes PULMONARY forms of tuberculosis, as it needs oxygen for its reproduction. The "bovine" type of stick (microaerophile) does not depend on the supply of oxygen and more often than the "human" type can cause extrapulmonary forms, including lymphadenitis, meningitis, bones, eyes, genitourinary organs, pulmonary lesions have a milder course, intrathoracic lesions are more often affected ( bronchiadenitis), subcutaneous (polyadenitis) and abdominal (mesadenitis) lymph nodes. Mycobacterium "Africanum" (aerophile) is considered an intermediate species, clinically and under a microscope similar to the first two. The "bird" type of stick (aerophile) can cause the same lesions, severe sepsis is also described, but it seems to be rare, since there is little described, optimum temperature its breeding is above 40 degrees. Ordinary laboratories are not aimed at identifying each of the types of mycobacterium tuberculosis, since the biological overlap is very high. All these forms of the disease are treated with the same drugs and give a reaction to.

The first two types of mycobacteria are of epidemiological significance in Russia; they are usually found in the sputum of humans and cattle suffering from the PULMONARY form of tuberculosis. It should be borne in mind that extrapulmonary forms (BC-) can also be contagious, this has been experimentally proven in goats.

There are data on people with tuberculosis in pulmonary hospitals and on the frequency of finding rods in sputum. In the 50s, the "bovine" species was found in 2% of pulmonary patients. In 2004, "bovine" stick is indicated from 10% to 15% in pulmonary patients and in 15 - 20% of patients with tuberculosis of the skin, bones and joints, peripheral lymph nodes, genitourinary system. "Closed" (BK-) pulmonary forms are difficult to investigate for the pathogen, like most extrapulmonary forms of tuberculosis. in many of these cases would be negative. Extrapulmonary forms of tuberculosis are deprived of the attention of phthisiatricians and are diagnosed at very late stages.

There are no statistical data on the frequency of infected (not sick!) people and animals with the bovine type of tubercle bacillus in our country.

The "bovine" type of tuberculosis is just as dangerous as the "human", but its epidemiology has not been studied due to the lack of an available method for determining the type of pathogen in pulmonary "closed" (CD-) and extrapulmonary forms of the disease.

2. How much can tuberculin tests be trusted, how specific are they, i.e. accurate?

The classics of immunology unanimously recognized that the specificity of skin allergic tests in infectious diseases is higher than that of serological immune reactions. The whole theory of infectious allergy was created on the example of tuberculosis allergy, served as a model infection. The study of tissue sensitization, delayed infectious allergy, is possible only by skin tests.

Tuberculin reactions are most pronounced in the initial, allergic period of the tuberculous process, when the lesions are not yet formed or are very small and cannot be identified.

"A latent infection is considered to be such an infectious process in which there are no clinical manifestations of the disease in the presence of viable microbes in the body. It must be borne in mind that the concept of "infection" implies the existence of a PROCESS, that is, the presence of interaction, the relationship between a microbe and a macroorganism. The existence of a process with latent infection can be established through pathomorphological examination or with the help of immunobiological reactions ", that is, tests with allergens. This was written by Prof. V.N. Kosmodamiansky about a latent infection in tuberculosis. cause sensitization, and cannot give any allergic, including "false-positive" reactions.The presence of a HIDDEN tuberculosis infection, (legally giving positive tuberculin reactions, that is, tuberculosis allergy) in the absence of a specific tuberculosis clinic during life, has been described many times by pathologists, Abrikosov's school -Strukov-Serov See.

Since the tuberculin test does not clearly correlate with the activity of the destructive process in the pulmonary focus of tuberculosis, phthisiatricians do not attach much diagnostic value to it. The intensity of this test is more consistent with allergic, INFLAMMATORY tuberculous processes without destruction. For a generalist, the results are important, its presence and the intensity of sensitization, against which infectious and allergic diseases occur, often very life-threatening (GLOMERULONEFRITIS, MENINGITIS, DISEASES OF THE BLOOD, VESSELS, SEROUS CAVITIES, JOINTS, INTESTINE, NERVOUS SYSTEM, ASTHMA, MYOCARDITIS , POLYARTHRITIS, UROGENITAL and many other diseases). We have reliably proved (and confirmed by treatment in severe cases) the fault of tuberculous allergy in the occurrence of the disease in a large number of patients, in the absence of pulmonary tuberculosis. with nephritis in 72 cases and with rheumatoid arthritis in 43 cases. Previously, the fault of tuberculosis infection in all these diseases was suspected only in some cases in combination with a clear active focus of tuberculosis in the lungs. Therefore, therapists should attach great importance to the intensity, persistence, timing and nature of tuberculin reactions, regardless of the presence or absence of a primary lesion in the lungs and the nature of the process in it. Cm. . In many cases, a DIAGNOSTIC TEST with helped us to identify the tuberculous nature of the inflammatory process (see "How to identify the culprit infection" on our website).

Non-pathogenic, i.e. harmless mycobacteria cannot create their persistent inflammatory foci and cannot cause sensitization in a person, therefore they cannot give a positive reaction to the allergen (), that is, to the test. If tuberculin-positive types of mycobacteria unknown in Russia are found, then they must be identified and treated. In other countries (eg in the USA) in 30% of cases it is caused not by human (M.tuberculosis humanis), but by bovine (M.tuberculosis bovis), intermediate (M.tuberculosis africanum) and other types of pathogenic mycobacteria that are in Africa, but we don't have it yet. They are identified, among other things,.

Sensitization can only be caused by those infections that are able to create their own persistent focus (focal point) in the body and develop intracellularly. The strain meets these conditions, has its own persistent focus (often in the regional lymph node), which is why it is able to induce both immunity and sensitization almost in parallel.

To treat or not to treat a child with a strongly positive post-vaccination reaction? Be sure to treat prophylactically, reduce the intensity of sensitization. Academician A.E. Rabukhin and the Ministry of Health of Russia.

TUBERCULIN TESTS are specific and accurate, THEY CAN BE TRUSTED.

3. Can diaskintest replace the Mantoux test?

THUS, the intensity of allergic tests cannot reliably help to identify among those infected with VK - already sick, i.e. having a classic focus of a destructive form of the disease or an activated latent infection. This also applies to serological samples (in test tubes). So far, only a doctor can reliably do this on the basis of clinical signs of the disease.

Which clinic to look for in each case? Today we know three main clinical forms of tuberculosis

FIRST form - classic pulmonary;

3 comments on “DIASKINTEST vs MANTOU”

Hello, my name is Olga Redichkina, I am a medical journalist. Can I somehow contact the author of this text? I have questions, maybe he wants to become an expert in my article?

Hello. Tell me, please, can an infiltrate of beer tuberculosis with negative tests and diaskintes
those to be positive sputum test (bq+)?

The pathogenesis of lesions. Tuberculosis in humans is caused by two main types of mycobacteria - human (M. tuberculosis) and bovine (M. bo vis), less often avian mycobacteria (M. avium). Infection occurs by airborne droplets and airborne dust, sometimes through the mouth, when used food products infected with tuberculosis mycobacteria through the skin and mucous membranes.

Possible intrauterine infection of the fetus through the placenta.

With aerogenic infection, the primary infectious focus develops in the lungs, and with alimentary infection, in the mesenteric lymph nodes. In the development of the disease, primary, disseminated and secondary tuberculosis is isolated, which is an endogenous reactivation of old foci. With low body resistance and adverse social conditions, the pathogen can spread throughout the body from the place of primary localization and cause a generalized infection.

At the site of penetration of mycobacteria or areas most favorable for the reproduction of bacteria, a primary tuberculosis complex arises, consisting of an inflammatory focus (in the lungs it is an extra-pneumatic focus under the pleura), affected regional lymph nodes and a “path” of altered lymphatic vessels between them. Dissemination of microbes can occur broncho-, lympho- and hematogenous.

The formation of the primary complex is characterized by the development of granulomas in the form of tubercles (tubercles or tuberculosis). No granuloma formation characteristic features and is a cellular reaction. Mycobacteria are surrounded by leukocytes and all this accumulation is surrounded by epithelioid and giant (multinuclear) cells. Most often, the primary focus is observed in the lungs (Gon's focus). With good body resistance, mycobacteria can be in the tubercle for several years or for life. In most cases, primary lesions heal with complete degradation of the contents, its calcification and fibrosis of the parenchyma. With a decrease in immunity, primary foci are activated and progress with the development of a secondary process. Such reactivation usually occurs 20-25 years after the initial infection; usually it is provoked by stress, malnutrition and a general weakening of the body. According to statistics, 80% of people get lethal form of tuberculosis, the remaining 20% ​​- tuberculosis of other organs and tissues (disseminated tuberculosis). Tuberculosis affects the genitals, bones and joints, skin, etc.

Clinical manifestations. The incubation period for tuberculosis is relatively long - from several weeks to 5 years. The disease can develop acutely: severe shortness of breath, pain in the chest area. Reactive tuberculosis is manifested by cough, sometimes with hemoptysis; weight loss; night sweats; subfebrile body temperature. There are no symptoms specific only to tuberculosis, since tuberculosis is characterized by a variety of clinical forms and anatomical changes.

Immunity. Immunity in tuberculosis is non-sterile, due to the presence of Z-forms of mycobacteria in the body. Acquired immunity is a consequence of the activation of T-cells by the antigens of Mycobacterium tuberculosis. Therefore, the outcome of the disease is determined by the activity of cellular factors of immunity.

One of the protection factors is bacteriophages, which have an effect on both virulent and avirulent strains of tubercle bacilli.

Methods for diagnosing tuberculosis:

1. Microscopy. This method is simple, accessible, allows you to quickly give an answer. Ziehl-Neelsen-stained smears show red rods on a blue background. The disadvantage of this method is its low sensitivity (due to the very slow growth of mycobacteria, they may not get into the smear, they can be detected at a content of 100,000-500,000 mycobacteria in 1 ml of material).

2. With negative microscopy, a microbiological method is used: inoculation of the test material on nutrient media (usually Levenstein-Jensen).

For ease of isolation, antibiotics are added to the media to inhibit the growth of associated microorganisms. The advantage of this method lies in the possibility of obtaining a pure culture, which allows its identification and sensitivity to medicines. The disadvantage is the slow growth of Koch's sticks (from 4 to 14 weeks).

3. A mandatory method of examination is tuberculin diagnostics, based on determining the body's sensitivity to tuberculin. Mycobacteria contain endotoxins, which are released during cell breakdown. R. Koch isolated this toxin in 1890 and called it "tuberculin". There are several preparations of tuberculin. "Old" Koch's tuberculin is a 5-6-week culture in glycerol broth, sterilized with flowing steam (100°C) for 30 seconds, evaporated at 70°C to 110 of the original volume and filtered through porcelain candles. Koch's "new" tuberculin - dried Mycobacterium tuberculosis, pounded in 50% glycerol until a homogeneous mass is obtained. Tuberculin from bovine mycobacteria (M. bo vis) contains proteins, fatty acids, lipids. To set up the Mantoux reaction (proposed by a French scientist in 1908), Koch's "new" tuberculin is used. This reaction is administered intradermally. With a positive reaction after 48 hours (in the elderly - after 72 hours), a papule 10 mm in diameter with hyperemic edges is formed at the injection site. You should be aware that a positive result is not always a sign of an active tuberculosis process, just as a negative Mantoux reaction does not always indicate the absence of a process, since the reaction is usually negative in patients with immunodeficiencies.

4. For the early detection of tuberculosis patients, an X-ray (fluorographic from the age of 15) diagnostic method is used. According to the current directive documents, the frequency of its conduct is determined by the epidemiological situation with respect to tuberculosis and the groups of the population subject to examinations.

Tuberculosis prevention is ensured through early diagnosis, timely detection of patients and their clinical examination, neutralization of milk and meat of sick animals. Prevention consists in carrying out social events (improving the working and living conditions of the population, raising its material and cultural level).

For immunoprophylaxis, the BCG vaccine is used - attenuated bovine mycobacteria. In Russia, all newborns are vaccinated. In the USA - only in high-risk groups. Immunization, as a means of preventing tuberculosis, is not optimal, and the more serious the epidemiological situation for tuberculosis is, the less effective it is. The introduction of subsequent BCG revaccinations at an older age does not affect the incidence. Therefore, the most important thing in specific immunization is to protect children. After vaccination, for some time they refuse to perform skin tests to prevent hyperreactive complications (necrotic reactions, etc.).

M. bovis - causes tuberculosis in cattle and in 5% of cases in humans. Cattle are infected with tuberculosis by aspiration, by inhalation of infected dust, and also alimentary - through contaminated feed and water. Bacillus excretion in milk often occurs even in animals that do not have clinically significant changes. Due to this great importance has human infection with milk or dairy products obtained from sick animals.

Tuberculosis in cattle and birds is of particular danger for workers in livestock and poultry farming, meat processing plants, slaughterhouses, among which tuberculosis is of a pronounced professional nature.

Lesions in humans are prone to complications, generalization, exudative reactions and bronchogenic metastasis. Morphologically does not differ from M. tuberculosis. Methods for isolating the pathogen are also similar to human-type mycobacteria. M. bovis is isolated from 60 species of mammals, but cattle, camels, goats, sheep, pigs, dogs and cats pose an epidemiological danger.

Isolation scheme for Mncobacterium tuberculosis

Lumi-l "nonsense4 microscopy

Bacteriological method

M. leprae is the causative agent of leprosy (leprosy or Hansen's disease).

Leprosy has been known since antiquity. In the Middle Ages, it affected entire villages. Leprosy was treated with mystical horror, it was always shrouded in a veil of mystery. Leprosy became the basis of many literary plots. Stevenson, Conan Doyle, Jack London wrote about lepers. In medieval Europe, lepers were cut off from the world healthy people. The need for isolation remains the main condition for the fight against leprosy. With the diagnosis of "leprosy", a person is forced to break with his former life and settle in a leper colony. Starting from the XIV century. the incidence of leprosy in Europe has declined sharply, and leprosy now occurs in several countries as sporadic cases. Currently, there are about 2 million patients with leprosy in the world. The causative agent was discovered by the Norwegian scientist Hansen (1873).

Morphological and cultural properties. Leprosy sticks are straight or curved, the ends can be pointed or thickened, motionless, do not form spores and capsules, alcohol-, acid-resistant, gram-positive.

M. leprae is difficult to grow on nutrient media. Cultures develop very slowly (6-8 weeks), form colonies in the form of a dry wrinkled coating.

The epidemiology of leprosy is not fully understood. The selectivity of infection defies logic. IN medical literature describe a case when the eldest daughter cared for a father with leprosy, and the middle and youngest, who had the least contact with the patient, fell ill. Therefore, in each specific case it is impossible to identify the route of infection.

The reservoir of infection is a sick person. Presumably, infection occurs by contact or airborne droplets. The main way to combat leprosy remains the isolation of patients. The leading role in the spread of infection belongs to socio-economic factors, as evidenced by the high incidence in third world countries. In Russia, the incidence rate is low. In Lipetsk, Irkutsk, Leningrad regions - 1 patient each, in Rostov region- 70 people (Don is a territory endemic for leprosy - since the time when the Cossacks went on long trips).

The pathogenesis of lesions. Only people get sick with leprosy, so the source of the disease is a sick person. Pathogenesis is due to the formation of tubercles (like tubercles) in various organs and tissues, where the pathogen enters with the flow of blood and lymph. With good body resistance, the disease proceeds latently and may not manifest itself during life. The probability of the disease depends on the immune status of the human body. A severe form of the disease is considered lepromatous.

Clinical manifestations. The incubation period - from 3 to 5 years, sometimes delayed up to 20 years. At the onset of the disease, general symptoms of intoxication: fever, weakness, bone pain, etc. Skin lesions appear in the form of rashes, which are clearly limited spots (leprida) of different colors and sizes. Then there are other symptoms: lack of sensitivity to high or low temperature, to pain.

If the lesions are localized on the face, then the patients notice the loss of eyebrows and eyelashes, and continuous infiltrates give the appearance of a "lion's face", the patient loses his voice.

Laboratory diagnostics. Material from the patient is obtained by vigorous scraping of the nasal mucosa, puncture of enlarged lymph nodes. Diagnosis is carried out by microscopy. Smears are stained according to Ziehl-Neelsen. Also, a false test with the allergen M. leprae (lepromine test) is used for diagnosis, which is always negative for facial lesions. This is due to the lack of cellular immune responses.

Scheme of isolation of the causative agent of leprosy LEPRO

Express method

"Scraping from the mucous membrane of the nose, 1 points or a histological section of leprosy nodes, discharge of ulcers, etc.

okr. according to Ziel-l Nielsen

Method for detecting hypersensitivity

Test with lepromine

Treatment. There are legends in medical circles about scientists who inoculated themselves with leprosy to test the means of salvation being tested. However, the experiments were not successful: there is still no drug that defeated leprosy. Often intensive chemotherapy is given throughout the life of a patient with leprosy. The main drugs are sulfones, rifampicin, clofazilin.

QUESTIONS FOR SELF-CHECKING

1. Name the main morphological and culipural properties of mycobacteria.

2. What groups of mycobacteria cause disease?

3. What do you know about the properties of tubercle bacillus?

4. What can be said about the epidemic situation of tuberculosis?

5. What is "tuberculin"? Its practical application.

6. What is tuberculosis prevention? What is BCG?

7. Name the methods of diagnosing tuberculosis.

8. What pathogen causes tuberculosis in animals?

9. What is "leprosy"?

10. What are the clinical manifestations of leprosy?

§ 2. Genus corlnebacterIUm

The genus Corinebacterium includes bacteria with club-shaped thickenings at the ends, pathogenic for humans and animals, plants and non-pathogenic corynebacteria (diphtheroids).

Morphological and cultural properties. Corinebacterium diphtheriae (from Latin corina - mace, diphtera - skin) are straight or slightly curved sticks, polymorphic, well stained at the poles. They do not form spores, they do not have flagella, they have a microcapsule. Diphtheria bacteria have club-shaped thickenings at the ends. By consistency, it is a jelly-like mass. It was first isolated from spirilla. In the strokes, the sticks are arranged at an angle, resembling the appearance of spread fingers. Gram-positive. Aerobes or facultative anaerobes. Opt t growth - 37°C, pH 7.2-7.6. They grow well on media containing protein (blood agar, clotted serum, serum agar). On blood agar, it forms small, round colonies with even edges, grayish in color. On tellurite agar, they form large, rough (R-shaped) rosette-shaped colonies of black or gray color.

Diphtheria coryne bacteria are subdivided into three biovars according to cultural and biological properties: gravis, mitis and intermedius.

enzymatic properties. Diphtheria bacilli do not coagulate milk, do not decompose urea, do not emit indole, hydrogen sulfide is weakly emitted. They ferment glucose and maltose.

Toxin formation. Corynebacterium diphtheria produces a very strong exotoxin. Non-toxigenic strains do not cause disease. The toxigenicity of corynebacteria diphtheria is associated with lysogenicity (the presence of moderate phages - prophages in toxigenic strains). Diphtheria exotoxin is a complex complex that exhibits all the properties of an exotoxin - thermolabile, highly toxic, has a specific effect on the body (affects the heart muscle, adrenal glands and nervous tissue). Under the action of 0.4% formalin, within a month, at 40 ° C, the toxin is converted into anatoxin, which is then used for the immunoprophylaxis of diphtheria (ADS, DPT). The toxin is not stable in the external environment; it is destroyed by light, O2, when heated to 60°C. Toxin activity is expressed in units of Dim (Dosis letalis minima - minimum lethal dose). 1 ED Dim diphtheria toxin is equal to the lowest concentration that kills a guinea pig weighing 250 g on the 4-5th day.

Antigenic structure. On the basis of the structure of O- and K-antigens, 11 serovars of the causative agent of diphtheria are distinguished, which are established by the agglutination reaction.

resistance. The causative agents of diphtheria are quite resistant to various environmental factors. At room temperature on various subjects can be stored from 1 to 2 months. When heated to 60°C and exposed to 1% phenol solution, they die after 10 minutes. Corynebacteria are resistant to low temperatures and drying.

The pathogenesis of lesions. The entrance gate of diphtheria is the mucous membranes of the nasopharynx, eyes, and less often the skin. At the site of the introduction of the pathogen, a diphtheric film of a grayish-yellow color is formed, which is hardly separated from the underlying tissues. This process is accompanied by regional lymphadenitis. If the diphtheria film grows, the inflammatory process from the pharyngeal mucosa spreads to the larynx and bronchi, which can lead to asphyxia. Diphtheria bacteria produce a very strong exotoxin, when it enters the bloodstream, toxinemia develops. The toxin affects the heart muscle, adrenal glands, and kidneys. A person can die from heart failure.

Clinical manifestations of diphtheria depend on the site of introduction of the pathogen. There are diphtheria of the throat (80-90% of cases), diphtheria of the nose, skin, eyes, genital organs, etc. The incubation period is from 2 to 10 days. The most susceptible to diphtheria are children from 1 to 7 years old. The disease begins with fever, pain when swallowing, the appearance of a film on the tonsils, swollen lymph nodes.

After the transfer of diphtheria, a person develops long-term immunity.

Prevention. Prevention of this disease consists in early diagnosis and hospitalization of patients, identification of bacteria carriers.

Specific prophylaxis is carried out by introducing diphtheria toxoid into the body, which is part of the combined vaccines: DPT, ADS and ADS-M. Immunization is carried out starting from the age of 3 months, then repeated revaccination for both children and adults (see the vaccination calendar).

Classification of diphtheria by anatomical localization

I. Oropharyngeal diphtheria:

1. Localized - 75%:

a) island; b) membranous.

2. Common - 7-10%. Clinical 3. Toxic 20%:

forms: a) subtoxic; b) toxic I st. gravity; c) toxic II st. gravity; d) toxic III Art. gravity; e) hypertoxic.

P. Respiratory tract diphtheria:

1. Diphtheria of the larynx (localized croup);

2. Diphtheria of the larynx and trachea (common croup);

3. Diphtheria of the larynx, trachea and bronchi (descending croup);

4. Diphtheria of the nose:

a) catarrhal form; b) membranous form; c) toxic form.

Sh. Other localizations of diphtheria:

1. Diphtheria of the eye (conjunctival form):

a) catarrhal; b) membranous; c) toxic.

2. Diphtheria of the oral mucosa:

a) diphtheria of the cheeks; b) sublingual region; c) language; d) lips.

3. Diphtheria of the genital organs (anal-genital).

4. Diphtheria of the esophagus.

5. Diphtheria of the skin.

Scheme for isolating the causative agent of diphtheria with methylene

(according to Leffler), crystal - violet according to Gram

Film, discharge of the nasopharynx, eyes, ears, urethra, wounds, etc.

Bacteriological method

Blood-tellurite media, Bunin's environment, Klauberg's conjunct, etc.

Accumulation medium

Pure culture of methylene

(according to Leffler), crystal - violet according to Gram

Enzymatic properties

§ 3. Genus bordetella

Bordetella pertussis, the causative agent of whooping cough, was isolated from patients with whooping cough in 1906 by T. Borde and O. Zhang.

Morphological and cultural properties. Whooping cough pathogens are small ovoid-shaped sticks (cocco-bacilli), gram ~, weakly stained with aniline dyes. They have a capsule-like shell and inclusions of vo-lutin. They do not have spores or flagella. Aerobes. Opt - 37°С. They do not grow well on simple media. Bordetella agar and AMC are used for the primary isolation of Bordetella. Increased CO2 content accelerates the growth of these pathogens. On Borde-Gangu agar with the addition of blood, bordetella form colonies resembling droplets of mercury. Colonies of whooping cough bacteria are granular and smooth. In blood broth, they form turbidity and give a small precipitate.

resistance. In the external environment, bordetella are not stable. In sunlight, they die after 1 hour. Sensitive to disinfectants.

Further:

Infection of humans with Mycobacterium bovine tuberculosis was formerly very common in England and Europe due to the large infestation of cattle and infection of humans through milk. Cattlemen also sometimes become infected by the respiratory route. Cats and dogs are susceptible to the disease through contaminated milk from cows or from humans. It is difficult to say whether they in turn infect a person.

Mycobacterium tuberculosis of the bovine type is as virulent in humans as it is in the human type. Bacteriologically, they differ in three ways:
1) Mycobacteria of the bovine type grow faster, and human, more slowly in the presence of glycerol. Since the latter is used in conventional cultures, bovine mycobacteria can be suspected by dysgonic growth.

2) Mycobacteria of the bovine type are highly virulent for the rabbit; human-type mycobacteria cause only local lesions.

3) All human type strains are niacin positive, usually to a high degree, while bovine type give only a weak reaction, and "anonymous" mycobacteria, with rare exceptions, are negative.

Type of disease. In the past, tuberculosis caused by bovine mycobacteria was often extrapulmonary, since infection through milk naturally occurred more often in childhood. Due to the age of infection, hematogenous tuberculosis was common. When infected through milk, the tonsils were primarily affected with a glandular component in the cervical lymph nodes, or the intestines with a glandular component in the mesenteric lymph nodes and sometimes secondary abdominal tuberculosis. Due to the route of infection, pulmonary tuberculosis was uncommon unless it occurred hematogenously or by direct contact with cows.

value at present. By the end of 1960, all cow herds in England were declared free from tuberculosis, although there were occasional breaches of control and minor epidemics. Mycobacterium bovine tuberculosis is still occasionally isolated from older, previously infected patients, usually from lesions of the cervical lymph nodes or kidneys. In a national survey in England in 1963, bovine mycobacteria were obtained in cultures from 0.2% of newly diagnosed patients with respiratory tuberculosis and over 1% of cases in rural areas of Western Scotland in 1963-1965. . Bovine tuberculosis has been completely eliminated in all Scandinavian countries, except for relapses of an old disease, but it is still an important, albeit declining, problem in many other European countries. It has indeed been eliminated in North America. Bovine tuberculosis is considered irrelevant in most tropical and developing countries, either because they do not drink milk or because if they drink it, they boil it first.

Methods for determining the risk of bovine tuberculosis to the population. With regard to bovine tuberculosis, two organizational measures are being carried out in many countries: pasteurization of milk and the creation of "certified" herds of tuberculin-negative cattle. In the UK, the latter was achieved through financial support to farmers, free tuberculin testing and the slaughter of tuberculin-positive cattle in the later stages of the campaign.

Tuberculosis is an infectious, chronic disease of all kinds of animals and humans, characterized by the formation of specific nodules in various organs that undergo caseous necrosis and calcification.

Historical reference. Tuberculosis has been known to mankind since ancient times. Hippocrates (4th century BC) described the clinical signs of tuberculosis in humans and recommended treatments. The term "tuberculosis" was first used by the French physician Lenek (1819) in 1869. Villemin established the infectiousness of tuberculosis.
The causative agent of the disease was discovered in 1882 by R. Koch. In 1890, he also made a diagnostic drug, tuberculin.

In 1924 And Calmette and S. Guerin produced the BCG vaccine - for the specific prevention of tuberculosis in humans.
Tuberculosis is registered in many countries of the world. In Russia, the prevalence of tuberculosis among animals is insignificant.
Eradication of tuberculosis serious problem and especially relevant because the disease is both zooanthroponotic and anthropozoonotic.

Economic damage. Tuberculosis causes great economic damage to animal husbandry, which is associated with a decrease in productivity, premature culling and delivery of animals for slaughter, lengthy and expensive anti-epizootic measures and other material costs.

The causative agent of the disease- Mycobacterium tuberculosis, a rod 0.5 to 8µ long, often bent at an angle, sometimes presented as grains arranged in a single line. The microbe is a strict aerobe, is not mobile, does not form a spore, is acid-resistant, and is also alcohol- and antimorphine-resistant. The acid resistance of tubercle bacillus is used to differentiate it from other non-acid resistant bacteria. Tuberculosis bacillus contains adipose tissue and therefore does not perceive paints well, but, being stained when heated with carbol fuchsin, it retains this paint better than other microorganisms. When smears are treated with a weak solution of sulfuric acid, tuberculosis bacteria do not discolor (they stain red with magenta), but other microbes discolor (Ziehl-Neelsen method). In smears, they are located singly or in groups.

Three types of tubercle bacillus are known: human (humanus), bovine (bovines), bird (avium), which are varieties of the same species. Under certain conditions, they can sometimes change, turning into other types. Most often there is a transition of the bovine type to the human. In 1937, Wales isolated a special type of bacteria from the field mouse, called the Oxford strain. This strain is close to the bovine type. Other scientists consider it the fourth type of tubercle bacillus - mouse.

The main difference between the types is their unequal virulence for certain species of animals and humans.

Mycobacterium tuberculosis (human species) causes tuberculosis in humans. Pigs, cats, dogs, cattle, fur-bearing animals are also susceptible to this type of mycobacteria, and birds (with the exception of parrots) are not susceptible.

Mycobacterium bovis (bovine species) causes tuberculosis in all types of agricultural, wild animals, including fur animals, as well as humans. Birds are not susceptible to this type of mycobacteria.

Mycobacterium avium (avian) causes tuberculosis in domestic and wild birds, pigs are susceptible to this type of mycobacteria; animals of other species and humans are rarely infected.
In nature (in peat and soil) there are opportunistic atypical and saprophytic mycobacteria that are close to avian-type mycobacteria in their morphological and cultural properties.

Animals infected with such mycobacteria may react to tuberculin for mammals, which is used by practical veterinarians during planned antiepizootic measures, which causes certain difficulties in the allergic diagnosis of tuberculosis.

Tuberculosis bacillus, due to the content of fatty and waxy elements, is very stable in the external environment and to the effects of disinfecting substances. In air-dried pieces of affected lungs, microbes remain virulent for 200 days, and in soil and manure they remain viable for up to 4 years, and in birds up to 10 years. Sunlight decontaminates bacteria in sputum after only 72 hours. In products obtained from sick animals, the causative agent of tuberculosis persists: in milk up to 19 days, in oil up to 300 days, in cheese 145-200 days, in frozen meat up to 1 year, in salted meat 60 days. In the corpses of cattle and birds, mycobacteria persist from 3 to 12 months.
Heat has a detrimental effect on tuberculosis bacteria. Heating milk to 55 ° kills them after 4 hours, up to 85 ° - after 30 minutes, when milk is boiled, mycobacteria die - after 3-5 minutes.

Chemicals have a detrimental effect on bacteria over relatively long periods of time: a 5% solution of carbolic acid - after 24 hours, a 5% solution of formalin - after 12 hours, a solution containing 5% active chlorine - after 3 hours.
The best disinfectants are a 3% alkaline solution of formaldehyde (1 hour exposure), a suspension of bleach containing 5% active chlorine, a 10% solution of iodine monochloride, a 20% suspension of freshly slaked lime, a 5% solution of hypochlorite calcium, 1% solution of glutaraldehyde and other preparations.

epidemiological data. More than 55 species of domestic and wild animals and about 25 species of birds are susceptible to tuberculosis. Cattle and pigs are the most susceptible, minks are the most susceptible, and chickens are the most susceptible. Goats, dogs, ducks and geese get sick with tuberculosis less often. Very rarely sick sheep, horses, cats.
The main source of the causative agent of infection in tuberculosis are sick animals. They secrete bacteria with faeces, sputum, milk, and if the urogenital tract is affected, with sperm. In cattle with tuberculosis of the lungs, 1 g of sputum may contain up to 100,000 tuberculosis bacteria. Part of the sputum when coughing is sprayed into the air, and part is swallowed by animals and comes out with feces. A cow suffering from tuberculosis is able to excrete an average of 37 million tuberculosis bacteria per day with faeces. Excretions of animals suffering from tuberculosis infect the environment: premises, walking yards, pastures, watering places.

The factors of transmission of the infectious agent can be feed, water, bedding, manure, etc.

Infection with tuberculosis occurs more often during the stall period when animals are crowded. Young animals become infected mainly through milk and skim milk obtained from sick animals. Possible intrauterine infection of calves. Animals can become infected through contact with people with tuberculosis, especially milkmaids and calves who do not undergo annual medical examinations. On the pasture, infection is less common, since the bacteria die under the influence of sunlight, but if the summer is rainy and cold, then mass reinfection of animals is possible on the pasture. Adult cattle during the stall period of keeping are infected mainly by aerogenic means, on pasture - by alimentary; pigs become infected by feeding them undisinfected kitchen waste from hospitals, tuberculosis dispensaries, or by contact with sick birds. Dogs and cats - from people with an open form of tuberculosis or when eating milk and meat from sick cows.

Poor living conditions, inadequate feeding, excessive exploitation lowers the resistance of animals to tuberculosis. Sharp transitions from one condition to another, the replacement of feed, the lack of regular exercise on fresh air, tightness and dampness in the premises and other unsanitary conditions for keeping animals.

In cattle of beef breeds kept in the steppes, the incidence of tuberculosis is negligible. It is necessary, however, to deprive the cattle of the conditions to which they are accustomed, and resistance to tuberculosis falls, the cattle fall ill.

Tuberculosis usually spreads slowly in a herd, and mass reinfection of livestock occurs within a few months. The comparatively slow spread of tuberculosis is explained, on the one hand, by the length of the incubation period, and, on the other hand, by the fact that not all diseased animals are active bacterial excretors.

Most often, a certain number (sometimes significant) of diseased animals is detected in the spring, when the veterinary service conducts scheduled tuberculinization on farms, but sometimes cattle are re-infected on a pasture, especially if the summer is damp and cold.

Pathogenesis. Having penetrated into the body of an animal with inhaled air or through the digestive tract, tuberculosis bacteria enter the lungs or other organs through the lymphogenous and hematogenous routes. At the site of localization of tuberculous bacteria, an inflammatory process develops, followed by the formation of tuberculous nodules-tubercles the size of a lentil grain, grayish in color, rounded. In the center of the tubercle, dead cells under the action of mycobacterium toxins turn into a curdled mass.
Depending on the resistance of the organism and the virulence of bacteria, the tuberculous process can proceed benignly and malignantly.

In a resistant organism, tuberculosis bacteria are surrounded by epithelioid cells, from which giant cells are subsequently formed. This whole group of cells is surrounded by a ring of lymphocytes. Exudate is deposited between the cells and fibrin coagulates. The emerging avascular tuberculous tubercle (granuloma) is encapsulated. Tissue cells in the tubercle die due to lack of inflow nutrients, and under the influence of bacterial toxins, a curd mass is formed, impregnated with lime salts. With such a benign course of the disease, in such an encapsulated focus, tuberculosis bacteria in Eventually may die and further development the infectious process stops.

In cattle, tuberculosis of the serous membranes (pleura, peritoneum) is quite often observed - “pearl oyster”. In this form of the disease, inflammation is productive from the very beginning. Tuberculous tubercles undergo fibrinous degeneration and turn into dense shiny growths.

In an organism with reduced resistance, the process of delimitation and localization of the causative agent of tuberculosis is poorly expressed. Due to insufficient encapsulation, the walls of tuberculous nodules melt. Mycobacteria enter healthy tissue, which leads to the formation of new small (miliary) nodules. The latter merge with each other and form large tubercular foci. If the curd mass is released from these foci, for example, in the lungs through the bronchi, then cavities are formed. The pathogen spreads through the lymphatic vessels; when it enters the circulatory system, bacteremia occurs in the animal's body. Bacteria spread throughout the body, the process is generalized, many organs are affected (liver, kidneys, spleen, etc.).

The resistance of an animal organism depends not only on its initial state, but also on the conditions in which it is located. If there are favorable conditions for feeding and keeping on the farm, which increase the resistance of the organism, the development of the tuberculosis process that has begun can be delayed at a certain stage. Encapsulation and calcification in the body of animals can be subjected even to large tuberculosis foci. Immuring the causative agent of tuberculosis either leads to the containment of its reproduction, or ends with the death of the pathogen, and then the body of the sick animal recovers.

In the case of generalization of the tuberculous process and extensive lung lesions, gas exchange is disturbed, toxins of tuberculous bacteria reduce erythropoiesis, which causes anemia. If this is accompanied by intestinal damage, accompanied by a violation of the absorption of nutrients, then the animal will experience exhaustion and death.

The course and symptoms of the disease. The duration of the incubation period for tuberculosis ranges from two to six weeks. Tuberculosis in animals is chronic or latent, so clinical signs of the disease may appear months or even years after infection.

The onset of tuberculosis in animals in private household plots, peasant farms and agricultural enterprises is determined during routine diagnostic tests for tuberculosis (tuberculinization) by veterinarians by the presence of positive allergic reactions.
When positively reacting animals are sent for diagnostic slaughter, and during post-mortem examination of organs and lymph nodes, signs characteristic of tuberculosis are found.

Conditionally distinguish between active, or open, tuberculosis, when tuberculosis bacteria are excreted with bronchial mucus, feces or milk, and latent tuberculosis, when the bacteria are so isolated in the tuberculosis focus that they are not excreted.

With damage to the intestines, udder and uterus, the tuberculous process is always open, with damage to the lungs - not always, but very often. According to the localization of the pathological process, pulmonary, intestinal forms of tuberculosis are distinguished; in addition, in animals there are also lesions of the udder, serous integument (pearl oyster), genital form and generalized tuberculosis. The course of the disease in individual animals is generally similar, but there are some features.

In cattle tuberculosis proceeds mostly chronically or latently. In young animals - acute and subacute. Clinical signs of the disease are: fever (39.5-40°C), wet cough, especially in the morning. The mucus released when coughing sometimes contains scraps of dead tissue. In sick animals, shortness of breath is noted. Auscultation of the chest in the lung area reveals wet or dry rales. If the pleura is affected by the tuberculosis process in an animal, the animal will experience pain when pressed between the ribs. The sick animal is losing weight. The skin becomes dry and loses elasticity.

With generalized tuberculosis, the lymph nodes increase (submandibular, pharyngeal, parotid, cervical, prescapular, inguinal, knee folds, supraexudate). The affected lymph nodes are dense, sometimes bumpy, painful on palpation. An increase in mediastinal nodes leads to compression of the esophagus, and this disrupts the process of belching and causes chronic swelling of the scar.

If the udder is affected in animals with tuberculosis, then part of it, often the back, swells up, becomes painful and hard. Milk is squeezed out of the nipples with an admixture of blood or curdled mass.

With intestinal damage, intermittent diarrhea is initially observed, which then becomes permanent. A sick animal develops cachexia. The defeat of the uterus and vagina is accompanied by abortion, nymphomania, barrenness. A vitreous discharge with an admixture of pus is released from the vagina. The defeat of the genital organs in bulls is complicated by orchitis. The pearl oyster on the pleura can be established by auscultation.

Tuberculous process, as a rule, progresses slowly. The illness can last for many years. Some sick animals recover, and in those cases when the primary complex becomes sterile, the animal loses its sensitivity to tuberculin. The majority of animals with tuberculosis in appearance and general condition are no different from healthy ones. Tuberculous lesions are found only at slaughter.

Horses suffer from tuberculosis relatively rarely, mainly in farms where cattle suffer from tuberculosis, and the disease in them most often occurs latently. If the tuberculous process is strongly expressed, a strong emaciation of the animal is noted, although the appetite may persist for a long time. If the lungs are affected, a weak cough appears, the horse quickly gets tired in work. In some cases, there are cases of damage to the nasal mucosa with the presence of nodules and ulcers.

Young horses have tuberculosis of the intestines and mesenteric lymph nodes. In this case, we note a poor appetite, colic appears. Constipation is replaced by severe diarrhea. For equine tuberculosis, polyuria is characteristic, the amount of urine excreted increases by 3-4 times.

Pig tuberculosis observed in farms where there is tuberculosis-infected cattle or poultry. The disease in pigs is mostly asymptomatic. The most characteristic clinical signs are an increase in the submandibular, pharyngeal and cervical lymph nodes. Sometimes abscesses form in these nodes, after the opening of which fistulas remain, from which a purulent-curdled mass is released. With damage to the lungs, coughing and vomiting, shortness of breath are observed, with damage to the intestines, diarrhea. Sick pigs quickly lose weight.

In sheep and goats tuberculosis basically proceeds in the same way as in cattle. More often the disease is asymptomatic. With a strongly pronounced tuberculous process in patients, we observe coughing, nasal discharge, and emaciation. In goats, udder damage is characterized by the formation of hard, bumpy swellings, sometimes reaching a significant size.

Avian tuberculosis. Chickens get sick more often, geese, turkey ducks are much less common. The disease proceeds chronically with very unclear clinical signs. Sick chickens become lethargic, emaciation is noted while maintaining appetite. There is a blanching and wrinkling of the crest, the bird is inactive, egg production decreases, the pectoral muscles atrophy. Generalization of the tuberculous process is accompanied by damage to the intestinal tract. Vomiting, diarrhea are observed, causing a sharp exhaustion of the bird. Sometimes bones, joints are affected, lameness is noted. A sick bird develops anemia: the number of erythrocytes drops to 1 million, the hemoglobin content to 35%.

Tuberculosis in dogs. In dogs, tuberculosis is characterized by subfebrile fever, decreased appetite, lethargy, and gradual emaciation of the animal. There is a cough, nasal discharge. If the intestines are affected, then diarrhea occurs. On the basis of tuberculosis in dogs, synovitis and deforming osteoarthritis may appear. Death comes from complete exhaustion.

Camel tuberculosis. The cervical and submandibular lymph nodes are affected; there is a cough, sweating increases, fatigue is observed.

From furry animals silver-black foxes, minks and nutrias are susceptible to tuberculosis. Young people get sick more often. The disease is predominantly chronic; there is weakness, lethargy, progressive emaciation. When the lungs are affected, coughing, shortness of breath and rapid breathing are observed. If the intestines are affected, then diarrhea appears, less often constipation. Liver damage may be accompanied by jaundice. The fox on the skin of the neck sometimes develops non-healing ulcers.

Pathological changes. In large and small cattle, tuberculosis often affects the lungs and bronchial-mediastinal lymph nodes.

According to P.I. Kokuricheva (1950), in a patient with tuberculosis of cattle, the lymph nodes of the chest cavity are affected in 100%, the lungs in 99% of cases; other organs - rarely: liver-8%, spleen-5%, udder-3%, intestines-1%.

When opening the lungs, dense foci of a reddish-gray or yellowish color are found. The contents of the foci are cheesy or calcareous. Sometimes the foci look like purulent foci surrounded by a thin connective tissue capsule. Nodules of various sizes are scattered around such foci, from a pinhead to millet grain. The presence of caverns surrounded by a dense capsule is also characteristic. Tuberculous foci can be found, although much less frequently, also in other parenchymal organs, in the bone marrow and bones. The pleura is also affected, sometimes fusion of its sheets is observed. The so-called pearl oyster is characterized by the formation of small tuberculous nodules on the serous membranes of the chest and abdominal cavities with simultaneous growth of connective tissue. The accumulation of dense nodes in appearance resembles a cauliflower. On the cut of the lymph nodes affected by tuberculosis, a curdled degeneration is found. On the mucous membrane of the pharynx, small intestine and caecum, individual tubercles and ulcers of various sizes are noted, having a hard bottom, they are covered with a dry curdled mass.

At autopsy of the corpses of adult horses that have died from tuberculosis, changes are found mainly in the lungs, more often in the form of a miliary process. In foals, mesenteric lymph nodes are affected. The latter are enlarged, numerous cheesy-purulent foci are found in them. Nodules and ulcers are found on the intestinal mucosa. If the liver and spleen are affected by the tuberculous process, then they are enlarged several times. In horses, there is also damage to the serous membranes (pearl mussel).

At autopsy of a bird that has died from tuberculosis, specific lesions are found in chickens more often in the liver and spleen, in geese and ducks - in the lungs.
The liver and spleen are usually sharply enlarged, have a flabby texture and contain numerous tubercles located both in depth and along the periphery of the organ. Tuberculous foci of various sizes are sometimes found in in large numbers in the small and large intestines, where they are located in the mucous membrane and in the submucosal layer. On the mucous membrane there may be ulcers of various sizes. Lymph nodes of the mesentery are enlarged, contain caseous masses. In rare cases, tuberculous lesions are found in the kidneys, bones.

Diagnosis Tuberculosis is diagnosed in a complex manner, taking into account epizootic data, clinical signs and results of allergic, pathoanatomical, histological, bacteriological and biological studies.

The clinical method of diagnosis is of limited value, since in relation to large species animals using this method can isolate very few patients with tuberculosis.

The main method of intravital diagnosis of tuberculosis is allergic. Allows you to identify patients with any form of tuberculosis, regardless of whether the animal has clinical signs of the disease or not.

For the diagnosis of tuberculosis in cattle, buffaloes, pigs, goats, sheep, horses, camels, dogs, monkeys and fur animals, tuberculin is used - a sterile filtrate of killed cultures of the causative agent of tuberculosis of two types: dry purified (PPD) tuberculin for mammals and PPD - tuberculin for birds. Tuberculin PPD for birds is prepared from the causative agent of avian tuberculosis and is used to diagnose tuberculosis in birds and pigs.

The main intravital method for diagnosing tuberculosis in animals is an allergic intradermal tuberculin test. In horses, camels, buffaloes, the diagnosis is carried out by the eye method (ophthalmic test). If necessary, an ophthalmic test is carried out in cattle simultaneously with an intradermal test.

Tuberculinization is subjected to:

• cattle (buffalo) twice a year: in spring, before grazing, and in autumn, before putting cattle into winter keeping, and young cattle from 2 months of age, cattle of fattening groups - once a year;
• horses, mules, donkeys, sheep and goats - depending on the epizootic situation;
• all adult sows, as well as young animals after weaning in all breeding farms - once a year, and on other pig farms, depending on the epizootic situation;
• adult birds (older than two years) of the initial lines and grandparental flocks at breeding plants and selection and breeding poultry stations - once a year.

Animals belonging to citizens living on the territory of farms or in separate settlements, are examined for tuberculosis at the same time as tuberculinization is carried out on the farm.

With the intradermal method of tuberculinization, tuberculin is administered to cattle, buffaloes, zebu cattle, deer (marals) in the middle of the neck, bulls-producers - in the under the tail fold, camels - in the area of ​​the outer surface of the ear 2 cm from its base, goats - in the thickness lower eyelid; dogs, monkeys and fur-bearing animals (except for minks) - in the area of ​​the inner surface of the thigh or elbow crease; minks - intrapalpebrally into the upper eyelid; for cats - in the area of ​​the inner surface of the ear; for chickens - in the beard; turkeys - in the submandibular earring; geese, ducks - in the submandibular fold; pheasants - males - in the cavernous bodies of the head; peacocks, parrots, pigeons, cranes, herons, storks, flamingos - in the area of ​​the outer side of the lower leg 1 ... 2 cm above the ankle joint.

Before the introduction of tuberculin, the wool (hair) at the injection site is cut out (feathers are plucked out), the skin is treated with 70% ethyl alcohol.

Reading the reaction to the intradermal administration of tuberculin is carried out in cattle, buffaloes, zebu-like cattle, camels and deer after 72h; in goats, sheep, pigs, dogs, cats, monkeys, fur animals after 48h; at the bird after 30-36h. In points unfavorable for tuberculosis, cattle and camels are allowed to re-introduce tuberculin 72 hours after the first injection in the same dose and in the same place. Accounting and evaluation of the response to repeated administration is carried out after 24 hours.

When taking into account the intradermal reaction, the tuberculin injection site is palpated in each test animal, and the eyelids of the left and right eyes are visually compared in minks.

If a thickening of the skin is detected during reading at the site of tuberculin injection in cattle, buffaloes, zebu-like cattle, camels, deer, we take a cutimeter and measure the thickness of the fold in millimeters and determine the amount of its thickening, comparing it with the thickness of the fold of unchanged skin near the tuberculin injection site.

Animals are considered tuberculin responsive:

• cattle (except bulls), buffaloes, zebu-like, camels, deer, marals, antelopes - with thickening of the skin fold 3mm or more regardless of the nature of the swelling (swelling, soreness, increased local temperature);
• bulls, sheep, goats, elephants, rhinos, hippos, pigs, dogs, wolves and other representatives of predatory birds, dolphins, cats – with the formation of swelling at the injection site of tuberculin.

Intradermal tuberculin test - a highly specific reaction to tuberculosis. At the same time, it depends on the general immunoreactivity of the organism. In old, deep-feeding animals, in animals with low fatness, as well as in the case of a generalized tuberculous process, the reaction to tuberculosis may be weakly expressed or completely absent (anergy).

Veterinarians conducting tuberculinization should keep in mind that sometimes non-specific (para-and pseudo-allergic) reactions to tuberculin for mammals are possible, due to sensitization of the body by avian mycobacteria, pathogens of paratuberculosis and atypical mycobacteria, as well as other reasons. To differentiate nonspecific reactions, a simultaneous allergic test is used, which is carried out simultaneously with tuberculin for mammals and a complex allergen from atypical bacteria (CAM). If, when reading the reaction, the intradermal reaction to the introduction of CAM is more intense than to tuberculin for mammals, the reaction is considered non-specific by veterinarians, the material from such animals is examined for tuberculosis by laboratory methods.
Tuberculinization by the eye method (ophthalmoprobe) is used to diagnose tuberculosis in horses and other representatives of equids.

In cattle, this method can only be used simultaneously with an intradermal tuberculin test to additionally identify infected animals in farms that are unfavorable for tuberculosis or when selecting animals for diagnostic slaughter. Tuberculosis is most often confirmed by post-mortem examination in animals that respond simultaneously to examination in each of the samples.

Eye tuberculinization is carried out twice with an interval of 5-6 days between injections. Tuberculin in the amount of 3-5 drops is applied with a pipette or syringe without a needle to the conjunctiva of the lower eyelid or to the surface of the cornea with the lower eyelid pulled back.

Animals that have responded to the first injection of tuberculin should not be given the drug again.

Accounting for the results of an ophthalmic test is carried out after 6,9,12, and 24 hours after the first and 3,6,9 and 12 hours after re-introduction of tuberculin. A positive reaction is characterized by the formation of a mucopurulent or purulent secret that accumulates in the conjunctival sac or flows in the form of a cord from the inner corner of the eye, hyperemia and swelling of the conjunctiva. When taking into account the reaction, it is necessary to pull back the lower eyelid and examine the conjunctival sac, since the reaction may be limited to the short-term formation of a purulent secret in the form of grains.

Short-term hyperemia and lacrimation with the formation of a small amount of mucous secretion, as well as the absence of any changes, is assessed as a negative reaction.

If, during planned tuberculinization in a prosperous farm, animals that react to tuberculin are detected for the first time, then in order to clarify the diagnosis, under the supervision of specialists from the state veterinary network, a commission diagnostic slaughter of 3-5 animals with the most pronounced reactions to tuberculin is carried out and examined internal organs and lymph nodes. If at least one of the slaughtered animals has pathological changes typical of tuberculosis, the diagnosis is considered established.

If no changes in organs and tissues characteristic of tuberculosis are found in slaughtered animals, material is taken for bacteriological examination with a bioassay. If mycobacterium tuberculosis of bovine or human species is isolated from the material from slaughtered animals or if a bioassay is positive, the diagnosis is also considered established;

Immunity and specific prophylaxis.

The emergence and development of the tuberculous process is accompanied by irritation of the central nervous system. This causes an increase in the specific sensitivity of the body to tuberculosis bacteria and their toxins. Hypersensitivity, or allergy, is detected a few days or weeks after bacteria enter the body and marks not only the onset of an infectious process, but also the beginning of the formation of a certain degree of non-sterile immunity.
In tuberculosis, phagocytosis is rarely complete; bacteria multiply in neutrophils and macrophages. Agglutinins, precipitins, and complement-fixing antibodies also play a minor role in immunity. In the process of evolution, the body has developed the ability to delimit (immure) the pathogen in granulomas-tubercles. The degree of this ability, which depends on many factors, including the virulence of the pathogen, can be different, and this determines the outcome of the disease. Infectious (non-sterile immunity) lasts as long as tuberculosis bacteria are in the body; with their isolation or death, immunity also ceases.

For the specific prevention of tuberculosis in medical practice, the BCG vaccine is widely used, made by Calmette and Guerin (1924) from a culture of bovine mycobacteria.

Specific prophylaxis of tuberculosis with BCG vaccine is possible, but in most countries farm animals are not vaccinated against tuberculosis.

Prevention. Prevention and measures to combat tuberculosis are carried out in accordance with the current sanitary (SP 3.1 093-96) and veterinary rules (VP ​​13.3 1325-96).

Animal owners, heads of farms, regardless of the form of ownership, owners of peasant farms and others are obliged to:

• in the presence or acquisition of animals, register them at a veterinary institution, obtain a registration number in the form of a tag and monitor its safety;
• the purchase, sale, delivery for slaughter, pasture, placement on pastures and all other movements and regrouping of animals, the sale of livestock products shall be carried out only with the knowledge and permission of the state veterinary service;
• equip the necessary facilities for veterinary and sanitary purposes;
• take precautions when preparing feed to prevent their infection;
• quarantine for 30 days newly arrived animals for veterinary examinations and treatments;
• timely inform the veterinary service about all cases of illness in animals with suspected tuberculosis (loss of fatness, signs of pneumonia, enlargement of superficial lymph nodes);
• present, at the request of veterinary specialists, all the necessary information about the acquired animals and create conditions for their examination, research and processing;
• comply with zoohygienic and veterinary requirements when transporting, keeping and feeding animals, building livestock facilities;
• carry out the timely delivery of sick animals or the complete elimination of all unfavorable livestock at the direction of veterinary specialists;
• ensure the implementation of the restrictive, organizational, economic, special and sanitary measures provided for by these rules to prevent tuberculosis in animals, as well as to eliminate the epizootic focus in the event of its occurrence with the allocation of the necessary material, technical and financial resources.

Treatment. Animals with tuberculosis are handed over for slaughter. In herds, on farms, in settlements where the disease has already been established, animals that react to tuberculin are recognized as sick with tuberculosis and sent for slaughter within 2 weeks.