Anatomical and physiological features of newborn animals. Early postnatal period in animals. Anatomical and physiological features of young animals

01.11.2019

A bacterial infection, often becoming chronic, occurs in the form of tuberculosis in many animals, both agricultural and small domestic animals.

The disease manifests itself in the form of the formation of specific nodes - tubercles that develop in various organs.

They are resistant to various environmental factors and are able to remain viable for a long time in soil up to two years, and in water or meat from 2 months to a year.

An infectious disease of this species is not uncommon in animals. Cattle, dogs, less often cats are susceptible to its effects. Fish tuberculosis is not often diagnosed, but is found after an autopsy.

Signs of tuberculosis in animals

Tuberculosis in animals is extremely dangerous for humans. An animal can become infected with tuberculosis from a person, and a person can also get it from an animal. This can happen by airborne droplets and through the meat of an infected animal.

The disease is characterized by changes in the affected organs. The nodules formed in the organs have a diameter of 1 mm to 10 cm. These formations are impregnated with calcium salts and connective tissue.

The resulting tubercles have a layered structure, but a curdled mass is visible in the section - this is a necrotic tissue.

Formations in a cat or dog occur depending on the lesion, in a certain type of tissue. When the lungs are affected, microbacteria form large tubercles.

A sick dog may have lesions localized to the lung. In this case, the animal has other general changes on the organs:

Presence of the following signs of cavern, abscess, necrosis or lobar pneumonia.
Inflammatory processes of the lymph nodes.
Inflammatory process of the intestine.
The mucous membranes are covered with ulcers.
Changes in other organs (bone marrow, liver and heart).

The defeat of the microbacteria of the lung is accompanied by the occurrence of purulent inflammation. The vast cavity of the lung is filled with purulent mass and molten tissues.

Depending on the type of fish, tuberculosis can manifest itself in different ways. The symptoms are many and varied. It is worth highlighting the general signs of the presence of microbacteria:

Lack of appetite in representatives of fish;
The destruction of the fins;
Lethargy and thinness;
Pale color and eyeball;

In the chronic course, fish tuberculosis manifests itself in the form of ulcers and black spots.

Some varieties of aquarium fish develop specific symptoms.

Reddening of the body and skin lesions may be in the macropod. Over time, the scales fall out of the fish.
Eye prolapse from the orbits and an increase in the belly occurs in zebrafish.
Lack of contact with other inhabitants and lack of appetite in pecilia.
Stretching of the skin by fish. Bettas show a color change to transparent

Dogs and cats get TB

Dogs suffer from tuberculosis and cats. Infection occurs in an erogenous way. But there are times when an animal becomes infected through damaged skin. Other infection factors are food, water, milk or bedding.

The sputum of sick animals, humans or feces leads to infection with tuberculosis. Tuberculosis in dogs is curable.

But at this time the dog is in the incubation period, which is up to six weeks. Puppies that are breastfed are weaned from a sick mother.

Tuberculosis in cats is rare. It proceeds exclusively chronically. The animal during the illness looks lethargic, has a fickle appetite. In cats, tuberculosis is accompanied by sneezing.

A cough appears, the body is gradually depleted. In some cases, tuberculosis in cats exhibits symptoms and may be accompanied by an upset gastrointestinal tract.

When identifying the first symptoms of tuberculosis in a cat, you should immediately consult a doctor. Specialists will examine the feline representative and conduct a bacteriological study to determine the presence or absence of the pathogen.

In order for cats to not develop tuberculosis, it is important to follow the rules for keeping and feeding a pet:

Do not feed your cat raw meat or buy food from unverified suppliers.
In the case of walking the animal on the street, it is better to avoid tuberculosis dispensaries.

Infection of kittens with tuberculosis occurs through the digestive tract, by ingestion of microbacteria and can be dangerous to humans.

It can be infected milk or meat from sick animals. Tuberculosis in a cat can affect the lymph nodes, lungs, and intestines.

In addition to dogs, cats and fish, tuberculosis can affect cattle. In farm animals, several varieties of the disease are distinguished depending on the localization of the pathogen.

Thus, bacteria can infect the skin, lungs, intestines, bones and other organs. In cows, tuberculosis does not manifest itself in any way, and proceeds in a chronic form. But in calves, the disease is found in an acute form.

The development of the disease begins in the form of the formation of a primary tubercle at the site of the introduction of microbacteria. Lymph nodes in the animal increase. Over time, the animal becomes immobile, and the body temperature rises.

The process develops in the future as a remission or as an exacerbation. As a rule, cattle suffer from pulmonary tuberculosis. In cows, a progressive cough develops into a painful one.

When listening in cattle, an uneven breathing pattern is observed. The animal has shortness of breath, wheezing and groans. In a chronic course, all representatives of cattle become infected.

With tuberculosis of the intestine, rapid exhaustion occurs. The infected cow suffers from debilitating dyspepsia. She has fecal masses with impurities of blood and pus. The chronic form leads to the death of the animal.

Tuberculosis treatment

Tuberculosis is an infectious disease. Therefore, if a sick animal is identified, it is urgent to contact the veterinary service. Tuberculosis is dangerous not only for animals, but also for humans (especially for children).

To detect the disease, the animal is subjected to intradermal and ocular tuberculin tests - tuberculinization. In aged cattle, there is no reaction to the introduction of tuberculin. Cows from 11 years old, as well as birds, are handed over for slaughter. As a preventive measure, all livestock are inspected.

Pets are taken to a veterinary clinic, where they are left until the circumstances are clarified. Animals undergo a chest x-ray and a biopsy of the affected organ.

If a disease is detected, the dog remains in the clinic, where it is placed in an isolated box. Unfortunately, there is no cure for TB in dogs. Treatment is carried out with immunomodulators.

It is worth noting that dogs, however, like cats, after undergoing treatment, are prone to relapse. In addition, it is possible that they may be carriers of the infection for the rest of their lives.

March 24 - World TB Day. Mankind already knows a lot about this disease, but it still remains one of the most common and dangerous on a planetary scale. The vast majority of citizens regularly vaccinate their children with BCG and do not mind passing the Mantoux test and other options for detecting tuberculosis infection. Everyone knows that - around, you can get infected anywhere, got on the bus - and now mycobacteria are already in the lungs. But few people think that you can get infected in another way. For example, drinking fresh milk or even having close contact with a pet. Such cases of infection, of course, are rare, but you should be aware of such unexpected sources of infection.

MedAboutMe looked into how animals and humans infect each other with TB.

Mycobacteria is a very numerous genus of the Mycobacteriaceae family, and not all representatives of this genus are dangerous to humans, and of those that are pathogenic for us, not all of them cause tuberculosis. For example, M.leprae is the causative agent of leprosy (leprosy), a whole company of non-tuberculous mycobacteria (NTMB) is the cause of mycobacteriosis.

But still, the most famous disease caused by mycobacteria, of course, remains tuberculosis. The disease is dangerous, contagious, which may not declare itself for a long time, and is extremely common. Every year, the disease takes the lives of 1.5-2 million people. And according to some reports, mycobacteria live in the body of every third person on the planet.

The classical causative agent of human tuberculosis is M. tuberculosis. This mycobacterium belongs to the Mycobacterium tuberculosis complex (MTBC) group, which includes several closely related species that cause tuberculosis in humans and some animals. The group includes 6 types of mycobacteria.

How does the infection spread after infection?

The human body can react differently to the penetration of mycobacteria. They do not emit any toxins, so they can stay in the human body for a long time without causing pronounced negative reactions.

Typically, mycobacteria are inhaled into the lungs. When they reach the alveoli, the bacilli enter the interior of the alveolar macrophages. Most of the bacteria are then destroyed or inactivated. But a small number of them multiply inside macrophages and, when it dies, go into the lymph or bloodstream. Through the circulatory or lymphatic system, mycobacteria can reach other tissues and organs - the tops of the lungs, kidneys, bones and even the brain, penetrate into the regional lymph nodes. This causes an immune system response at the level of the entire body. There is an emergency mobilization of all available immune cells that destroy the vast majority of bacilli.

Only in 3-5% of normal healthy people, M. tuberculosis, if untreated, will break through the protective barriers of the immune system within two years after infection and begin to multiply rapidly, leading to an active form of tuberculosis. But the infection can lie dormant in the body for years, so that in 2-5% it is activated in more than 2 years. That is, only 5-10% of people with a healthy immune system, having contracted tuberculosis, will someday get sick during their lifetime.

The risks are higher in people with a weakened immune system for various reasons. For example, within a year, 8% of HIV-infected patients who are not receiving antiretroviral therapy will develop tuberculosis.

The second most common and dangerous to humans are M. bovis - mycobacteria that cause the so-called bovine tuberculosis in cows and other cattle. But in humans, it is rare - in a few percent of cases.

The first descriptions of bovine tuberculosis date back to the early 1800s. In 1865, it was shown that a tubercle bacillus obtained from one species of mammal can be injected into a representative of another species and thus cause disease. In 1882, Robert Koch stated that tuberculosis could be transmitted from animals to humans. And 20 years later, in 1902, scientists were already vigorously discussing the case of a child with tuberculous meningitis caused by mycobacterium M. bovis. Experts estimate that TB, spread through the milk of infected cows, was responsible for a significant number of deaths before people learned to recognize and treat it.

Humans are infected with M. bovis, as mentioned above, relatively rarely. On average, this is 1.5% of the total number of patients with tuberculosis. For example: in the USA it is 230 people a year, and around the world - about 120 thousand people. The most common sources are unpasteurized cow's milk and cheese.

The proportion of people infected with bovine TB is higher in countries where animal infections are poorly controlled at the state level. For example, in the United States, cattle on the American-Mexico border most often suffer from tuberculosis. If the state kills a sick animal, but does not pay sufficient compensation, then the population tries to hide cases of the disease, which contributes to the spread of infection. For example, in Nigeria, a significant proportion of the inhabitants eat the infected meat of a cow killed due to tuberculosis. According to the authorities, 6-7% of butchers and beef sellers are sick with bovine tuberculosis there.

And recently, the UK authorities reported two cases of human infection with bovine tuberculosis, but not from cows, but from domestic cats. Cases of transmission of infection to humans from dogs have also been reported.

It has long been thought that a person can catch bovine tuberculosis from an infected cow, but cannot transmit M. bovis to another person. Alas, it turned out that the transmission of bovine tuberculosis between people is also quite feasible, and even not only among patients with impaired immunity, but also between completely healthy people.

In 2005, scientists suggested that the famous writer, author of the famous books "1984" and "Animal Farm", was ill with bovine tuberculosis. And he got infected on a farm, which became the prototype of his "animal farm". It should be added that from birth Orwell was a sickly child who suffered from chronic bronchitis and had been ill several times with bacterial pneumonia. He also had dengue fever and smoked. According to scientists, he transferred his suffering during collapse therapy (introduction of air to “collapse” the affected lung) onto paper, displaying them in the scene of torture in the Ministry of Truth (“1984”).

The "species barrier" in the case of mycobacteria from the MTBC group is quite thin. "Human" tuberculosis affects not only humans and other primates, but also guinea pigs. But cattle, wild ungulates (antelopes, elk, deer, elephants, rhinos) and other herbivores (rabbits, tapirs, ground squirrels, hares), seals, otters and cats (not only domestic, but also lions, tigers, lynxes) , badgers, raccoons, moles are more susceptible to M. bovis, but rather resistant to the human version. Pigs and dogs are the least fortunate: they become infected with both types of mycobacteria.

Cases are known when sick owners infected their dogs - usually the latter died. However, in 2000, a case was also described of the death of several cows on a farm in the Czech Republic - the cause was Mycobacterium human tuberculosis. And the animals picked them up from their owner - a sick farmer.

Tuberculosis is an infectious, predominantly chronic disease of many species of agricultural and wild animals, including fur-bearing animals and birds, characterized by the formation of specific nodules in various organs - tubercles, prone to curdled decay.

History reference

Tuberculosis has been known since ancient times. Clinical signs of the disease in humans were described by Hippocrates in the 4th century BC. BC e. The term "tuberculosis" was first used by the French physician Lennek (1819), and the contagiousness of the disease was proved by J. A. Villemin (1865). The causative agent of tuberculosis was discovered by R. Koch (1882), who also produced tuberculin in 1890. The Russian researcher X.I. Gelman proposed tuberculin in 1888, but published the work only in 1892. In 1924, Calmette and Guerin produced the BCG vaccine for the prevention of tuberculosis in humans.

Animal tuberculosis is registered in many countries of the world. In most European countries, it has practically been eliminated.

A great contribution to the study of tuberculosis and the development of health measures was made by S. N. Vyshelessky, P. P. Vishnevsky, M. K. Yuskovets, I. V. Poddubsky, V. I. Rotov, A. V. Akulov, N. A. Naletov and others.

The causative agent is a microorganism of the genus Mycobacterium. There are three main types of the causative agent of tuberculosis:

1) M. tuberculosis (human species);

2) M, bovis (bovine species);

3) M. avium (bird).

In morphology and cultural properties, they are largely similar to each other; these are thin, straight, often slightly curved sticks 0.8-5.5 microns long, located in strokes singly or in groups. There are also branched, filamentous and cocci-like forms of the microbe. The shell of the microbial cell contains fat-like substances, granularity is noted in the protoplasm. Mycobacteria are strict aerobes, immobile, do not form spores or capsules, acid-alcohol resistant; stained according to the Ziehl-Nelsen method in bright red, and other microflora in blue (color table I, L).

For the cultivation of the causative agent of tuberculosis, glycerin MPA, MLP, potatoes, egg and synthetic media are used. Cultures of mycobacteria of the human species grow slowly - 20-30 days, bovine species - 20-60, avian - 11 - 15 days. In the absence of growth, crops are recommended to be kept in a thermostat for 3 months. The pathogenicity of certain types of the causative agent of tuberculosis for different types of animals and humans is not the same. So, people are most sensitive to the causative agent of the human species, pigs, cats, dogs, cattle, fur-bearing animals are also susceptible, but birds do not get sick! (except parrots). All agricultural and wild animals, including fur-bearing animals, as well as humans, are sensitive to the causative agent of the bovine species, but birds are immune. Birds, pigs are sensitive to the causative agent of the bird species, and other mammals - animals and humans - are very rarely infected with it. Animals infected with avian mycobacteria may react to mammalian tuberculin.

The species affiliation of the causative agent of tuberculosis is determined by the characteristics of their growth on artificial nutrient media and by setting up a bioassay on guinea pigs, rabbits and chickens.

Differentiation of species affiliation of the causative agent of tuberculosis in a bioassay.

Sustainability

Mycobacteria are very resistant to various environmental factors and chemicals. This property is explained by the presence of fatty substances in the microbial cell.

The causative agent of tuberculosis remains viable in manure for 7 months, in dried cow feces - up to a year, in soil - more than two years, in river water - up to 2 months; in meat frozen and stored in the refrigerator - up to a year, in salted meat - 45-60 days, in oil - up to 45, in cheese - 45-100, in milk - up to 10 days. Pasture areas where animals sick with tuberculosis were grazing remain infected throughout the summer period (VN Kislenko, 1972).

Heating milk to 70°C kills the causative agent of tuberculosis in 10 minutes, and boiling - after 3-5 minutes. The best disinfectants are an alkaline 3% solution of formaldehyde (exposure 1 hour), a suspension of bleach containing 5% active chlorine, a 10% solution of iodine monochloride and a 20% suspension of freshly slaked lime, applied by whitewashing three times with an interval of 1 hour

In addition to the pathogenic mycobacteria of the three types of causative agent of tuberculosis (pathogenic mycobacteria), there is a large group of atypical mycobacteria in the genus Mycobacterium. By morphological features, they are difficult to distinguish from the causative agent of tuberculosis, more often they are represented by coarser, thick, non-granular sticks, different in length. Atypical mycobacteria are widely distributed in nature, and many of them are saprophytes. Once in the body of animals, atypical mycobacteria are able to multiply in it, and create a short-term sensitization of the body to tuberculin for mammals.

epidemiological data

Many species of domestic and wild animals are susceptible to tuberculosis, including game animals and birds (more than 55 species of mammals and about 25 species of birds). Most often, this disease is recorded in cattle, pigs, minks and chickens; less often - in goats, dogs, ducks and geese; very rarely - in sheep, horses and cats. Monkeys are highly sensitive to tuberculosis. Among wild ungulates, marals are more likely to get sick. A person also suffers from tuberculosis.

The source of the causative agent of infection are animals with tuberculosis, from the body of which the pathogen is excreted with milk, feces, nasal discharge, sometimes with sperm. When cows are infected with any type of tuberculosis pathogen, mycobacteria are always excreted in milk.

Transmission factors of the causative agent of tuberculosis can be feed, water, pastures, litter, manure, etc. contaminated with secretions of sick animals. Young animals are mainly infected through milk and skim milk obtained from sick animals. Possible intrauterine infection of calves. Animals can become infected with the human species of the pathogen through contact with people with tuberculosis.

The route of infection is predominantly alimentary, but aerogenic is not excluded, especially when patients are kept together with healthy people in closed, poorly ventilated, damp rooms. Pigs are more likely to get sick when they are fed raw kitchen waste, as well as when in contact with TB-sick birds. Birds are infected by the alimentary route, but transovarial transmission of tuberculosis has also been established in chickens. Sick birds lay infected eggs. During the incubation of infected eggs, many embryos die, and some of the hatched chickens become a source of the causative agent of tuberculosis. Wild birds can be carriers of all three types of the causative agent of tuberculosis.

Tuberculosis among animals spreads relatively slowly. This is due to the duration of the incubation period of the disease (up to 45 days). Insufficient feeding, unsatisfactory living conditions (crowding, dampness) and other adverse factors reduce the overall resistance of the animal organism and contribute to the rapid spread of the disease. A certain seasonality in the manifestation of the epizootic process in tuberculosis is not observed. However, in cattle it is more often recorded during the stall period.

Pathogenesis

The causative agent of tuberculosis, having entered the body through the digestive tract with food or inhaled air, penetrates into the lungs or other organs. At the site of its localization, an inflammatory process develops, manifested by cell proliferation and exudation; there is an accumulation of multinucleated giant and epithelioid cells, surrounded by a dense layer of lymphoid cells. The exudate accumulated between the cells coagulates, forming a network of fibrin, an avascular tuberculous nodule is formed - a tubercle. It initially has a grayish color and a rounded shape; its size is from a pinhead to a lentil grain. Soon the nodule is surrounded by a connective tissue capsule. The tissue inside the encapsulated nodule, due to the lack of influx of nutrients and under the influence of pathogen toxins, dies and turns into a dry, crumbly mass resembling cottage cheese (caseosis).

If the primary tuberculous nodule develops only at the site of the introduction of the pathogen (lungs, intestines), then such a fresh, isolated focus is called the primary effect. From it, the pathogen with the lymph flow usually enters the regional lymph node, where pathological changes also develop. Simultaneous damage to the organ and the regional lymph node is called the complete primary complex. If the process develops only in the regional lymph node, then it is called an incomplete primary complex.

With a benign course of the disease, the primary focus undergoes calcification, a dense connective tissue capsule forms around it, and the further development of the infectious process stops. In an organism with reduced resistance, the process of encapsulation of the pathogen in the primary focus is poorly expressed. Due to insufficient regeneration of the connective tissue, the walls of the tuberculous nodule melt, while mycobacteria enter the healthy tissue, which leads to the formation of many small, translucent nodules (miliary tuberculosis). Small tubercles can merge with each other, forming large tuberculous foci.

Mycobacteria from tuberculous foci can enter the bloodstream, which leads to a generalization of the process and the development of tuberculous foci of various sizes in various organs (liver, spleen, kidneys, etc.). With a long course of the disease, large tuberculous foci and cavities can form in the lungs, sometimes reaching the size of a fist. A dense connective tissue capsule grows around them. Tuberculous cavities may communicate with the lumen of the bronchi. In such cases, their contents liquefy and are coughed up with sputum.

With a generalized form of tuberculosis and extensive lesions in the lungs, gas exchange is disturbed, erythropoiesis is inhibited, anemia is observed, productivity decreases, exhaustion and death of the animal occur.

Course and symptoms

Tuberculosis usually proceeds chronically, and often without clearly visible signs. A positive reaction to tuberculin in animals occurs on the 14-40th day after their infection (incubation period). Most animals with tuberculosis in appearance and general condition, especially at the beginning of the disease, do not differ from healthy ones. Sick animals are detected mainly by allergic and serological examination, tuberculous lesions are usually found only during post-mortem examination of organs. As a result of systematic planned studies of livestock (tuberculinization), it is possible to detect the disease in the initial stage. The appearance of clinically pronounced forms of tuberculosis indicates a long course of the disease.

According to the localization of the pathological process, pulmonary and intestinal forms of tuberculosis are distinguished; there are also lesions of the udder and serous integument (pearl oyster), genital form and generalized tuberculosis.

Conventionally, it is customary to distinguish between open (active) tuberculosis, when the causative agent of the disease is released into the environment with milk, feces, sputum when coughing, and closed (latent) in the presence of encapsulated foci without releasing the pathogen into the environment. With damage to the intestines, mammary gland, uterus, the process is always considered open. In cattle, tuberculosis often affects the lungs. With a strong lesion, they observe a slight increase in body temperature, a rare but severe cough; with a protracted course of the disease, the cough becomes weak, silent, but painful. Expectoration in cattle is almost not observed, bronchial mucus separated by coughing is swallowed or excreted through the nose. In sick animals, shortness of breath, a decrease in appetite, fatness and productivity are noted.

Visible mucous membranes are anemic. On auscultation of the lungs, wheezing is detected, and on percussion - areas of dullness. Intestinal damage, which is accompanied by diarrhea, is accompanied by rapid exhaustion and increasing weakness of the sick animal.

The lesion of the mammary gland is characterized by an increase in the supraventral lymph nodes, which become dense, bumpy, and inactive. In the affected udder lobes, compacted painless foci are felt, with a significant lesion, the configuration of the affected lobe changes. During milking, watery milk with an admixture of blood or curd mass is released. With the defeat of the genital organs in cows, there is an increase in sexual hunting, barrenness, and in bulls - orchitis.

With generalized tuberculosis, superficially located lymph nodes (submandibular, prescapular, knee folds, supra-pituitary) are inactive.

Tuberculosis in pigs is asymptomatic. Sometimes there is an increase in the submandibular and pharyngeal lymph nodes. Abscesses may appear in the affected nodes, after opening of which a purulent-curdled mass is released. With extensive lung lesions, coughing, vomiting, shortness of breath occur. Sheep and goats are rarely and asymptomatically ill with tuberculosis. With a strongly pronounced process, the clinical signs are similar to those in cattle.

Tuberculosis in birds is chronic, with unclear clinical signs. The generalized form is accompanied by lethargy, decreased egg production, exhaustion (atrophy of the pectoral muscles). When the intestines are affected, diarrhea is observed; liver - icteric staining of the mucous membranes and skin. Lameness, tumor-like formations on the plantar surface of the extremities are sometimes noted.

Among fur-bearing animals (foxes, minks, nutrias), young animals are more often affected by tuberculosis. In patients, weakness and progressive exhaustion are noted, with a pulmonary form - cough, shortness of breath. Damage to the intestines is accompanied by diarrhea, and the liver is accompanied by icteric staining of the mucous membranes. In foxes, sometimes long-term non-healing ulcers appear on the skin.

pathological changes. A characteristic feature of tuberculosis is the presence in various organs and tissues of the animal of specific nodules (tubercles) ranging in size from millet grain to chicken eggs and more. Tuberculous foci are surrounded by a connective tissue capsule, their contents resemble a dry, crumbly, cheesy mass (caseous necrosis). With prolonged illness, tuberculous nodules can become calcified.

In ruminants, tuberculous lesions are more often found in the lungs and lymph nodes of the chest cavity. In the lungs, dense, reddish-grayish foci are found, on the cut they are shiny, greasy (lack of necrosis), more often with caseosis in the center; sometimes the foci have purulent foci. Occasionally, caverns of various sizes are found (cows, goats). The lymph nodes are most commonly affected. They are enlarged, dense, bumpy, with caseous disintegration of the tissue in the center of the node.

With the defeat of the serous integument, multiple (pearl mussel) dense, shiny tuberculous nodules are found on the pleura and peritoneum, reaching the size of a hazelnut. The intestinal form of tuberculosis is manifested by rounded ulcers with roller-like edges on the mucous membrane of the jejunum and ileum.

In cattle with tuberculosis, the lymph nodes of the chest cavity are affected in 100% of cases, the lungs - in 99, the liver - in 8, the spleen - in 5, the udder - in 3, the intestines - in 1% of cases (P. I. Kokurichev, 1950) . In pigs, tuberculous lesions are more often found in the lymph nodes of the mesentery and head, and less often in the liver and other organs. In poultry, they are localized mainly in the liver (90% of cases), spleen (70%), bones and intestines.

They put it on the basis of the analysis of epizootic data, clinical signs and the results of allergic, serological (RCC with tuberculosis antigen), pathoanatomical, histological, bacteriological and biological studies. The clinical method of diagnosing tuberculosis is of limited value, since the clinical signs of the disease in animals are not typical enough, and at the beginning of the disease they are not at all.

The main method of in vivo diagnosis of tuberculosis is an allergic study. For the study, tuberculin (allergen) is used - a sterile filtrate of killed cultures of the causative agent of tuberculosis. We prepare two varieties of tuberculin: dry purified tuberculin (PPD) for mammals and dry purified tuberculin (SHPD) for birds.

Dry purified tuberculin for mammals (protein purified derivative - PPD) consists of freeze-dried precipitated proteins of the culture filtrate of the causative agent of bovine tuberculosis, grown on a synthetic nutrient medium. It is used for allergic diagnosis of tuberculosis in all mammals.

Dry purified tuberculin (PPD) for birds is similar in appearance and manufacturing technology to DTP for mammals. It is prepared from the culture filtrate of the causative agent of avian tuberculosis and is used to diagnose tuberculosis in birds and pigs.

Tuberculinization methods. The main method of in vivo diagnosis of tuberculosis in animals is an allergic test with a tuberculin test. In horses, an ophthalmic test is used. In some cases, in cattle, it is placed simultaneously with intradermal.

As an additional method in the diagnosis of tuberculosis in cattle, a simultaneous allergic test is used, which is carried out simultaneously with purified tuberculin for mammals and purified complex allergen from atypical mycobacteria (CAM).

Animals are examined for tuberculosis from the age of 2 months; breeding stock of cattle, buffaloes and camels - regardless of the period of pregnancy; sheep, goats, pigs, deer (marals), horses and donkeys - not earlier than one month after birth.

Place of introduction.

With the intradermal method of research, tuberculin is administered to: cattle, buffaloes, zebu, deer (marals) in the region of the middle third of the neck; bulls are allowed to inject into the skin of the infracaudal fold, pigs - in the area of the outer surface of the auricle at a distance of 2 cm from its base (on one side of the auricle, PPD for mammals is injected, on the other - PPD for birds). Pigs aged 2-6 months. It is better to inject tuberculin into the skin of the lumbar region, stepping away from the spine by 5-8 cm (on the one hand, tuberculin is injected for mammals, on the other - for birds), using a needleless injector brand IBV-01. Goats, sheep, dogs, monkeys, fur-bearing animals (except minks) are injected with tuberculin in the area of the inner surface of the thigh; minks - intrapalpebrally into the upper eyelid; camels - into the skin of the abdominal wall in the groin area at the level of the ischial tuberosity; kuram—in the beard; turkeys - in the submandibular earring; geese, ducks in the submandibular fold; pheasants, peacocks, parrots, pigeons, cranes, herons, storks, flamingos - in the area of the outer surface of the lower leg, 1-2 cm above the ankle joint. The wool at the injection site of tuberculin is cut out (the feathers are plucked out), the skin is treated with 70% alcohol.

For tuberculinization, special needles for intradermal injections with a double tube (MRTU No. 46-84-62) or needles No. 0612 and syringes with a slider with a capacity of 1-2 ml are used. Needleless injectors are widely used to administer tuberculin to animals.

Tuberculin during intradermal tuberculinization is administered once in a volume of 0.2 ml to all mammals, except for monkeys and minks, as well as birds (they are at a dose of 0.1 ml).

Accounting and evaluation of the reaction. In cattle, buffaloes, zebu, camels and deer, they are carried out 72 hours after the administration of the drug; in goats, sheep, pigs, dogs, monkeys, fur-bearing animals - after 48; in birds - after 30-36 hours. The local reaction to the introduction of tuberculin can be assessed as positive or negative.

The reaction is considered positive if a diffuse (without clear boundaries with the surrounding tissue), pasty consistency, painful inflammatory swelling is formed at the injection site of tuberculin, accompanied by hyperemia and an increase in local temperature. In some animals, the reaction manifests itself as a dense, painless, distinctly contoured swelling (Fig. 1).

Cattle, buffalo, zebu, camels, and deer are considered tuberculin responsive if they have the above changes at the site of tuberculin injection and thickening of the skin fold by 3 mm or more compared to the thickness of the intact skin fold near the site of tuberculin injection.

Stud bulls, tuberculinized in the subcaudal fold, are considered responsive to the formation of an inflammatory swelling at the injection site of tuberculin and thickening of the skin fold by 2 mm or more.

In goats, sheep, pigs, dogs, monkeys, fur-bearing animals and birds, the reaction is considered positive with the formation of swelling at the site of tuberculin injection, and in minks - with swelling of the eyelid.

The intradermal tuberculin test is a highly specific reaction to tuberculosis. However, it depends on the general immunoreactivity of the organism and the sensitivity of animals to tuberculin. In animals of low fatness, old, deep-feeding, as well as with a generalized tuberculous process, the reaction to tuberculin may be mild or not manifest (anergy). It should also be taken into account that sometimes non-specific (para-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. However, nonspecific reactions are unstable and disappear after a few months.

Rice. 1. Positive reaction to tuberculin: A - in a cow; B - pigs; B-birds

Differentiation of specific reactions from non-specific, if necessary, is carried out by a simultaneous test with avian tuberculin or a complex allergen from atypical mycobacteria (CAM) and laboratory tests.

Tuberculinization by the eye method is carried out twice with an interval of 5-6 days. Tuberculin (3-5 drops) is applied with an eye dropper to the conjunctiva of the lower eyelid or to the cornea of the eye (with a drawn lower eyelid). The reaction is taken into account after the first injection after 6, 9, 12 and 24 hours, after the second - after 3, 6, 9 and 12 hours. It is considered positive if a mucopurulent or purulent secretion occurs from the inner corner of the eye, accompanied by hyperemia and edema conjunctiva.

Allergy testing for animal tuberculosis is only allowed to be carried out by veterinarians who have completed a special training course, who are familiar with the technique of administering diagnostic drugs and have experience in assessing allergic reactions.

The diagnosis of tuberculosis is considered established: when a culture of the causative agent of tuberculosis is isolated or when a positive result of a biological test is obtained. In cattle, in addition, the diagnosis is considered established upon detection in the organs or tissues of animals of pathological changes typical of tuberculosis.

Upon receipt of positive results of allergic tests for tuberculosis, the diagnosis of the disease is carried out by slaughtering 3-5 animals with the most pronounced reactions to tuberculin and examining internal organs, bones and lymph nodes. In the absence of typical changes in tuberculosis, pieces of organs and lymph nodes are taken, which are sent to a veterinary laboratory for bacteriological examination.

All herds, including previously reacting animals, are tested simultaneously with tuberculin for mammals and RAM allergen. In herds, on farms, in settlements where the disease has already been established, animals that react to tuberculin are recognized as suffering from tuberculosis.

Animals sick with tuberculosis are not treated, they are subject to slaughter. In disadvantaged fur farms, tubazid (isoniazid) is used to prevent tuberculosis in minks. The drug is given with food at a dose of 10 mg/kg of the animal once a day for 75 days.

Immunity

In tuberculosis, it is non-sterile, remaining as long as the mycobacteria are in the body. Phagocytosis is incomplete and phagocytosed mycobacteria do not die. Agglutinins and complement-fixing antibodies are produced in the body, but their role in immunity is insignificant. Protection is mainly determined by the body's ability to stop the pathological process, limit the pathogen in granulomas-tubercles. For the specific prevention of tuberculosis in young cattle and minks, a dry BCG vaccine is used, which is used in medicine. Clinically healthy animals are vaccinated with it.

Prevention and control measures

Measures to combat tuberculosis provide for the protection of prosperous farms from the introduction of the infectious agent from outside, systematic research to detect diseased animals in a timely manner, the improvement of farms that are unfavorable for tuberculosis by slaughtering sick animals, the isolated rearing of healthy young animals and the implementation of a set of veterinary, sanitary and organizational and economic measures, aimed at protecting healthy livestock and destroying the causative agent of tuberculosis in the external environment; protecting people from TB infection.

In prosperous farms, all measures should be aimed at protecting the farm from the introduction of the pathogen. To this end, farms are staffed with healthy animals from farms that are free from tuberculosis. Newly admitted animals during the 30-day quarantine period are examined for tuberculosis. Feed is purchased only from farms free of tuberculosis. The return coming for the feeding of young animals is pasteurized, and the combined food waste is subjected to heat treatment. Persons with tuberculosis are not allowed to serve animals, and keeping poultry on the territory of livestock farms. Periodically carry out preventive disinfection of livestock buildings, the destruction of rodents and ticks, take measures to improve the feeding and maintenance of animals. In breeding farms, it is strictly forbidden to use peat for animal feed and bedding.

For the purpose of timely detection of animals suffering from tuberculosis and monitoring the well-being of farms (farms) for this disease, routine diagnostic tests of animals for tuberculosis are carried out annually. Examine cows, heifers and young cattle from 2 months of age, bulls, sows, boars, camels intended for sale for breeding purposes.

Twice a year, cattle of breeding farms and farms supplying animals for the acquisition of livestock complexes, milk and dairy products directly to children's and medical medical institutions, rest homes or to the trading network, as well as farms territorially bordering on disadvantaged areas, are examined for tuberculosis. tuberculosis points. Cattle belonging to citizens living on the territory of these farms are examined simultaneously with the number of farms.

On breeding pig farms and reproductive farms, sows are examined before weaning piglets, and boars - 2 times a year. In other farms, sows, boars and, if necessary, young animals from 2 months of age are examined once a year.

Control over the well-being of poultry and fur farms for tuberculosis is mainly carried out by examining and post-mortem examination of dead and dead animals and birds, as well as by the allergic method. Horses, mules, donkeys, and sheep are tested for tuberculosis in farms that are unfavorable for this disease.

In the event of tuberculosis, the farm (farm) is declared unfavorable, quarantine is established and a calendar plan of measures to eliminate the disease is drawn up.

In farms that are unfavorable for bovine tuberculosis, buffaloes, reacting animals are immediately isolated and handed over for slaughter within 15 days. Young animals born from sick animals are fattened in isolated conditions and handed over for slaughter. The rest of the animals (not responding to tuberculin) of the dysfunctional farm are examined for tuberculosis every 60 days until two consecutive negative results are obtained in the group, after which two more control studies are carried out with an interval of 3 months. If negative results are obtained and there are no other indications for tuberculosis, this group of animals is recognized as healthy.

Calves born from animals of a dysfunctional farm that do not respond to tuberculin are grown in isolation, fed with the milk of healthy cows or neutralized milk (skim milk) of mothers. At 2 months of age, they are examined for tuberculosis by the intradermal method.

Calves that respond positively to tuberculin are isolated and after fattening they are handed over for slaughter. Non-responders are examined 2 more times with an interval of 60 days, then after 3 months. Upon receipt of a negative result for the entire group, they are recognized as healthy and used for production purposes only within the farm.

Improvement of farms with a significant lesion of livestock with tuberculosis (more than 25% of animals) is carried out by handing over unfavorable livestock for slaughter.

The success of the fight against tuberculosis largely depends on the activities of farm managers, who are called upon to provide the necessary assistance to veterinary specialists in conducting diagnostic studies, disinfection work, to implement a set of preventive measures aimed at creating a high sanitary culture in animal husbandry, increasing the natural resistance of the animal organism, equipping facilities with veterinary - sanitary purpose, strictly follow the requirements of the instructions for combating the disease.

In areas unfavorable for tuberculosis, it is recommended to create special groups (detachments) of veterinary specialists to carry out work on mass studies of animals for tuberculosis.

Under the terms of the quarantine, it is prohibited to keep animals with tuberculosis in herds and in common livestock buildings, as well as the organization of any kind of temporary and permanent concentration points and isolation farms for keeping such animals on farms. In areas that are unfavorable for cattle tuberculosis, it is not allowed to create inter-farm complexes, farms and other enterprises for raising heifers. On all farms in such areas, on-farm farms (departments, brigades, plots) should be organized for the isolated rearing of young animals. Livestock purchased by farms or consumer cooperation organizations from the population living in the territory of farms (settlements) that are unfavorable for tuberculosis are subject to immediate delivery for slaughter without fattening and fattening (in transit), regardless of weight standards.

It is forbidden to export non-disinfected milk obtained from cows of a dysfunctional farm, farm, herd in a settlement, to milk processing enterprises, for sale in the markets, for use in a public catering network, etc. Such milk is subject to primary processing directly on a dysfunctional farm (on the farm) for the entire time until the disease is completely eliminated and quarantine is lifted. At the same time, milk obtained from cows with a clinical manifestation of tuberculosis is prohibited from being used for food purposes and for animal feed. It is disinfected by adding 5% formaldehyde or another disinfectant to milk. Given this, sick cows should not be milked. Milk from cows that react to tuberculosis in the study is disinfected by processing into melted butter - raw or by boiling.

Dairy products from non-reacting cows of an unfavorable herd are disinfected at a temperature of 90 ° C for 5 minutes or at a temperature of 85 ° C for 30 minutes.

Dairy enterprises should release the return to farms only after it has been disinfected by pasteurization or heat treatment with live steam.

In specialized complexes, on farms for growing heifers (heifers), when a disease is established in young animals of the technological (age) group in which patients are identified, all heifers of this group are handed over for slaughter within 30 days, the rest of the animal population of the complex, farms - within 6 months (no more). Insemination of heifers is prohibited. During the recovery period, the introduction of heifers from supplier farms into the complex, to the farm is stopped, and in the future they are not allowed to be recruited as inter-farm enterprises for raising heifers with new livestock.

At beef production complexes and other fattening farms, when tuberculosis is established, all animals of a disadvantaged group are branded with the letter “T” and handed over for slaughter within 15 days. The remaining livestock is examined for tuberculosis every 60 days by an allergic method or the issue of surrendering all animals of the complex (farm) for meat is decided.

When infection of cattle with the causative agent of avian tuberculosis or atypical mycobacteria is established, and also when animals responding to tuberculin are detected in a safe herd (on a farm), but tuberculosis has not been established in them by previous studies, the herd (farm) is considered free from tuberculosis.

In pig farms (on farms) where infection of pigs with the causative agent of bovine or human tuberculosis has been established, all pigs that react to tuberculin (including pregnant sows), as well as boars and fattening livestock, are immediately handed over for slaughter. The remaining sows that do not respond to tuberculin are handed over for meat after farrowing, young animals - after rearing. On disadvantaged farms, insemination of sows is prohibited. The elimination of the source of tuberculosis of pigs is carried out no more than 6 months.

Horses are examined by an ophthalmic test. Reacting animals are slaughtered, and the rest of the population is examined every 60 days until a negative single result is obtained, on the basis of which the study group is recognized as free from tuberculosis.

Goats and sheep are examined by tuberculin test. Reacting ones are handed over for slaughter, and the rest of the livestock is examined for tuberculosis every 60 days until a negative result is obtained for the group.

When deer (marals) in an unfavorable herd are infected with tuberculosis, they are examined for tuberculosis until negative results are obtained for the herd. Clinically ill and tuberculin-responsive animals are slaughtered. Deer (marals) are examined for tuberculosis in November-February (males additionally in July-August), and young animals - after being transferred to winter roads.

When establishing tuberculosis in dogs, animals reacting to tuberculin (females together with offspring) are killed, the skins from them are used without restrictions. In nurseries, animals of a disadvantaged group are tested with tuberculin every 60 days until negative single group results are obtained.

When tuberculosis is diagnosed in fur-bearing animals, they are subjected to a clinical examination, sick animals (females with offspring) are isolated. During the period of maturation of the skin, they are fed daily with tubazid in a therapeutic dose (according to the instructions for its use). Animals are killed after the skin has matured, which is used without restrictions. For the rest of the animals of the disadvantaged group (farm), tubazid is added to the feed in a prophylactic dose; minks in such a farm are vaccinated with BCG vaccine for a protective purpose.

A fur farm (farm) is considered to be healthy if during one production period (from whelping to slaughter for the skin) no changes typical of tuberculosis are found in the organs of dead and killed animals.

In poultry farms, when tuberculosis is established, all the birds of a dysfunctional poultry house (zones, workshops, departments) are handed over for slaughter, veterinary and sanitary measures are taken, and after the quarantine is lifted, a new herd is formed from healthy pullets. On dysfunctional farms, it is necessary to maintain cleanliness, disinfection, disinfestation, deratization, sanitary repairs of livestock buildings and other veterinary and sanitary measures in accordance with current instructions.

For disinfection in households, they use: a suspension or a clarified solution of bleach; a solution of neutral calcium hypochlorite; hypochlorite or hexanite containing at least 5% active chlorine; drug DP-2; 1% aqueous solution of glutaraldehyde; alkaline formaldehyde solution containing 3% formaldehyde and 3% sodium hydroxide; 5% solution of technical sodium phenolate; 20% suspension of freshly slaked lime by whitewashing three times with an interval of 1 hour.

For aerosol disinfection of cleaned and hermetically sealed premises in the absence of animals, a 40% aqueous solution of formaldehyde is used.

The surface layer of the soil is disinfected with a 3% alkaline solution of formaldehyde or bleach. Pasture areas on which herds grazing unfavorable for tuberculosis are allowed to be used after 2 months in the summer in the southern regions and 4 months in the rest.

Manure, bedding and food residues from animals sick or suspected of being ill or infected with tuberculosis are destroyed or disinfected by biological, chemical or physical means.

A livestock farm (department), a farm, a settlement is recognized as cured of tuberculosis after the complete cessation of the disease of animals with this disease, the delivery of all sick animals for slaughter, the implementation of a complex of final organizational, economic, veterinary and other measures provided for by the instructions for combating the disease. An act is drawn up about this, on the basis of which the chief veterinarian of the district (city) submits to the local authorities a proposal to remove the tuberculosis quarantine from the unfavorable point.

In farms recovered from tuberculosis, after the quarantine is lifted, restrictions remain on the sale of animals for breeding and production purposes and their display at exhibitions, broods of cattle for four years, pigs - for one year.

Pathogen: Mycobacterium tuberculosis was discovered by Robert Koch in 1882. The causative agent of human tuberculosis is M. Tuberculosis; cattle - M. bovis; birds - M. Avium, these are thin, straight, often slightly curved sticks, located singly or in groups, aerobic, immobile, do not form spores and capsules. For the cultivation of the causative agent of tuberculosis, glycerin MPA, MPB, potatoes, egg and synthetic media are used. Mycobacteria remain viable in manure for 7 months, in feces - 1 year, in water - 2 months, in oil - 45 days, in cheese - 45-100, in milk - up to 10 days. Heating to 70°C kills in 10 minutes, and boiling inactivates after 3-5 minutes.

Epizootology. Course and symptoms.
Susceptible: all kinds of animals.

Pathogen source: sick animals and virus carriers.

Ways of transmission: aerogenic; through damaged oral mucosa, less often through udder teats and vagina, transmission factors - feed, manure, water, bedding, care items.

Incubation period: from 2-6 weeks before the onset of allergic reactions.

Tuberculosis is mostly chronic and asymptomatic.

In cattle, the lungs or intestines are more commonly affected. Pulmonary tuberculosis is accompanied by cough and other signs of damage to the lungs and pleura. With intestinal tuberculosis, diarrhea is observed, followed by constipation, excretion of mucus mixed with blood with faeces. With the defeat of the udder in cattle, the lymph nodes are enlarged, the udder becomes bumpy. Tuberculosis of the genital organs in cows is manifested by increased estrus, in bulls - by orchitis. With generalized tuberculosis, an increase in superficial lymph nodes is observed, animals lose a lot of weight, quickly get tired. They lose their appetite, mucous membranes are anemic.

In sheep and goats, tuberculosis occurs, as in cattle. In pigs - an increase in the submandibular, pharyngeal and cervical lymph nodes. Tuberculosis is rare in horses and is mostly latent. Tuberculosis of birds occurs with unclear clinical signs. Observe emaciation, inactivity, blanching and wrinkling of the crest, atrophy of the pectoral muscles. The generalization of the process is accompanied by intestinal damage.

Pathological and anatomical changes. A characteristic feature of tuberculosis is the presence in various organs and tissues of the animal of specific nodules (tubercles) ranging in size from millet grain to chicken eggs and more. Tuberculous foci are surrounded by a connective tissue capsule, their contents resemble a dry, crumbly mass (caseous necrosis). With prolonged illness, tuberculous nodules can calcify.

Diagnostics. Pathological material is sent both during the life of the animal (outflow from the nose, bronchial mucus, milk, especially with an increase in the supra-suppressive lymph nodes, feces, urine), and posthumously (the affected parts of the organs and lymph nodes are bronchial, pharyngeal, mediastinal, prescapular, supra-extended. Bird corpse ( or a carcass) are sent as a whole - the affected liver, spleen, lungs, ovaries are examined. Tuberculinization, histological, bacteriological studies, bioassay, serological studies (RSK) are carried out.

Differential diagnosis. Pasteurellosis, paratuberculosis, actinomycosis, dictyocaulosis, in pigs - lymphadenitis caused by atypical mycobacteria, in birds - leukemia.

Prevention and treatment of tuberculosis

Treatment is not carried out, sick and positively reacting animals are destroyed.

Prevention and control measures are based on the protection of prosperous farms from the introduction of infection, the systematic study of animals to identify patients, the improvement of farms that are unfavorable for tuberculosis, and the protection of people from infection with tuberculosis. In prosperous farms, the main method of animal research is planned total intradermal tuberculinization. All animals entering the farm are quarantined for 30 days. Tuberculosis is considered established if, in animals that respond to tuberculin, the diagnosis is confirmed by pathological and anatomical data and laboratory tests. Improvement of farms disadvantaged by tuberculosis is carried out by slaughtering sick animals, isolated rearing of young animals, implementation of veterinary and sanitary and organizational and economic measures. The farm is considered recovered from tuberculosis after the cessation of detection of sick animals, the receipt of negative results of control studies, the final disinfection of livestock buildings and a set of economic measures provided for by a special instruction.

Veterinary and sanitary examination. Skinny carcasses, if any form of tuberculosis damage to organs or lymph nodes is found in them, as well as carcasses, regardless of the state of fatness, heads, internal organs, including the intestines, with a generalized tuberculosis process, are sent for disposal.

Carcasses of normal fatness, except for carcasses of pigs, in the presence of tuberculous lesions in the lymph nodes or other tissues, are sent for the production of meat loaves, canned food or boiling. The internal fat is melted.

Affected organs and tissues are disposed of. If tuberculous calcified foci are found in pig carcasses only in the submandibular lymph nodes, the latter are removed, the head together with the tongue is sent for boiling, and the carcasses, internal organs and intestines are released without restrictions. If only the mesenteric lymph nodes are affected, only the intestines are sent for disposal, and the carcass and other internal organs are released without restriction.

If tuberculosis-like lesions caused by corynobacteria are found in the lymph nodes of pig carcasses, the carcass and organs are released without restrictions after removal of the affected lymph nodes. If a tuberculous lesion is found in the bones, all the bones of the skeleton are sent for disposal, and the meat (in the absence of tuberculous lesions) is sent for boiling or canned food.

Collapse

Carriers of Koch's wand can be not only people, but also animals. Birds, dogs, pigs and cattle are sick. Tuberculosis in cows is no less dangerous disease for humans, since transmission between them is also possible. To prevent infection, you need to know what symptoms the pathology has, and how it occurs in our smaller brothers.

What is bovine tuberculosis?

Tuberculosis of cattle is an infectious pathology in which the body of an animal is affected by the introduction of mycobacteria into it. An infected animal becomes a potentially dangerous object for all living organisms surrounding it. For:

chickens;
pigs;
ducks;
dogs;
cats;
horses;
cats, etc.

Even a person can become infected from a cow, which is why it is important to identify an infectious individual in a timely manner.

pathogens

Bovine pathology is caused by the bacteria Mycobacterium bovis. They also enter into a single species with those bacteria that infect the human body. M. bovis can mutate under other conditions and cause active tuberculosis in another living organism.

Bovis die from ultraviolet radiation. Resistant to alkalis and acids. In a humid and warm environment, they can be viable for a long time.

Causes and sources of infection

Bovine tuberculosis is contagious. If you come into contact with an infected animal, you can become infected with a person. Pets are a potential danger. It is less common in wild animals.

The sources of infection include several factors. It's possible:

by inhalation of tubercle bacilli, which, during coughing or sneezing, were thrown into the air by an infectious individual (especially if the room where the animals are located is not ventilated);
the calf becomes infected from the mother if she drinks her milk or colostrum;
through salivation, if animals eat from one trough;
through faeces and urine (relevant in stalls that are rarely cleaned);
by contact with a wild animal (badgers are often carriers of infection).

To avoid mass infection, and in the future, the death of cattle, it is necessary to diagnose the disease in a timely manner and begin treatment. It is important to place an infectious animal separately from others.

Signs and symptoms

The first signs appear on the 87th day after contact with mycobacterium, if infection has occurred. There are times when the MBT is in the body for several years and is waiting for the immune system to weaken. It is at this point that pathology will begin to develop. A predisposing factor will also be old age, stress, comorbidities, or poor nutrition.

Symptoms of tuberculosis in cattle are as follows:

If tuberculosis has affected the lung, then a cough is noted, often manifested in the morning, with excessive physical exertion, in wet weather and cold. Rarely, there is shortness of breath or a change in breathing.

The last stage is the hardest. There are enlarged lymph nodes, sometimes they burst, and the fluid from them flows into nearby organs. In addition, they interfere with the proper functioning of the digestive system. This results in constipation or diarrhea.

Diagnostics

To identify pathology in a cow, you should resort to certain diagnostic methods.

Initially, of course, the owner should pay attention to clinical symptoms. Any change in the behavior and general condition of the cattle should alert.

To diagnose tuberculosis, complex measures are used. Often the infection is known after the slaughter. For this, animal meat is studied in the laboratory.

Before confirming the infection with Koch's wand, other pathologies should be excluded. After that it is recommended:

Apply tuberculin test. The vaccine contains the antigen of mycobacteria, after the introduction it shows the result. Usually you need to wait from 2 to 3 days. Such vaccination is required every six months, it is performed by veterinarians in the neck area or in the crease under the tail. If the injection site is thickened by more than three mm, then the reaction is positive (the animal is infected). In any case, it is impossible to rely only on this method of examination, since everything depends on the age of the cow, its immunity and other factors.
It is also advisable to examine the animal's milk. Such an analysis is more accurate, but expensive, and you will have to wait 1-2 months.
For the final diagnosis, material for research is taken from the lymph node or lung after slaughter. Sowing and biochemical research methods are carried out. Growing a microorganism takes a long period of time (more than three months).

The use of the epizootological diagnostic method is justified, in which all possible routes of infection and the number of infected individuals are identified.

Can a person get infected?

Not only another animal, but also a person can become infected from cattle. A sick bull is dangerous, as it becomes a source of infection with tuberculosis.

Being near

If the owner of a sick animal breathes the same air as the cow, and previously she coughed or sneezed, it is possible to become infected in 85%. This is possible during milking, stall cleaning, etc.

In addition, if an open wound comes into contact with infected meat during slaughter, infection also occurs. In cow faeces, MBC is viable for about two months.

The fecal-oral route of infection is available even to humans. If it is bad to wash your hands after cleaning the feces of cattle or it is not enough to maintain the hygiene of the animal.

Drinking cow's milk

Is it possible to drink the milk of a cow infected with tuberculosis? Yes, but it must be boiled for at least five minutes. If you drink unboiled milk of a sick individual, then there is also a risk of infection. LSD found in milk will enter the body and begin to multiply actively. When buying such a product, you should always boil it and only then use it.

Can a cow get infected from a human?

Mycobacteria can change and adapt to any organism. As a person can get infected from an animal, so can an animal from a person.

The routes of infection are the same. Most often, this is an airborne route and the ingestion of the patient's sputum into the body of a cow.

Treatment and disinsection

Sick animals are not subject to treatment. They can infect the entire herd and the people around it. These animals are sent to be slaughtered.

After the farm where the cow was found, the TB patient is under quarantine. Tuberculin tests are done regularly. If a new sick individual is detected, it is immediately eliminated. All this lasts as long as the patients are detected. All the time the premises are disinfested, constant airings are made.

If more than 20% are infected, then they switch to radical methods:

All diagnostic procedures are removed.
All cattle are slaughtered.
Milk is boiled for 5 to 10 minutes.
The premises where there were cows are being cleaned. Then the floor is torn off and everything is treated with a disinfectant solution (formaldehyde, caustic salt, lime with 5% chlorine).
Everything that is left of the animals (including the torn floor) is disposed of.
If there was no cement under the floor covering, but only earth, then the 20-cm layer is removed and sent to the veterinary laboratory, where it is examined. Feces are also brought there. Do not use contaminated feces for fertilizer.

After all, a new floor is laid, new feeders are attached and everything is re-disinfected. A new farm is being brought in.

All cattle must be tested with tuberculin.

It is possible to bring out new cows for grazing to the place where tubinfected ones were grazed only after two years.

Prevention

To prevent infection with tuberculosis in cattle, you need:

be responsible for the hygiene of the cows themselves and the premises where they are located;
buy feed only from trusted suppliers;
conduct tuberculin diagnostics in animals every six months;
at the slightest deviation and the appearance of non-specific symptoms, contact a veterinary clinic;
exclude workers with a positive Mantoux test;
when acquiring a new premises, carry out disinfestation, it is also done periodically in all stalls;
fight against rodents.

Conclusion

Tuberculosis in cows is a dangerous disease that can disable the entire herd, infect other animals and even humans. To prevent infection, milk should be boiled before drinking, stalls should be kept clean, and cattle should be checked periodically for tuberculosis.