Bovine tuberculosis: symptoms and diagnosis, treatment and vaccination

Tuberculosis is a disease of bacterial origin, which affects all types of warm-blooded creatures: humans, wild and domestic animals, birds. The pathology is characterized by high contagiousness (infectiousness), lethality. Tuberculosis occurs latently or chronically in cattle. Infected individuals are a potential danger to the herd and humans. Cattle owners should know all the information on how to suspect the first signs of pathology.

Historical background

Tuberculosis has a long history of study. According to official sources, his symptoms were identified during the study of ancient Egyptian mummies.This discovery confirms the fact that the disease existed several thousand years ago. The "father of medicine", Hippocrates, was the first to describe the clinical manifestations of pathology.

French doctor Willemin established the contagiousness of tuberculosis. The scientist also proved that animals are also affected by the disease, described the ways of transmission between them and humans. The causative bacterium was discovered by Robert Koch in 1882. This put an end to all scientific debate about whether there is a link between animal and human tuberculosis.

Cows, pigs and horses in captivity have been found to be more susceptible to pathology.

Economic damage

Tuberculosis is included in the structure of significant and especially dangerous animal diseases. The epizootic situation remains tense not only in Asia and Africa, but also in developed countries - England, Germany, the USA. In Russia, more than 25 million heads of cattle are infected annually. The most disadvantaged regions for tuberculosis are the Moscow region, Tatarstan, Bashkortostan.

The disease causes significant damage to farms and private lands. A sharp decrease in productivity, premature culling, forced slaughter of individuals, long and expensive preventive measures - all this significantly hits the pockets of cattle owners. The economic damage from tuberculosis in Russia over the past 40 years has amounted to more than 84 billion rubles. The country has lost millions of tons of meat, milk, offspring. The cost of improving the epizootic situation exceeded 27 billion.

Pathogen and source of infection of cows

The disease is caused by mycobacteria (Koch's sticks). These are oblong, immobile, bent microorganisms. They develop without access to oxygen, do not have adaptations for movement. Mycobacterium tuberculosis is widespread in the environment and is able to remain active for a long time. For example, in soil and manure, mycobacteria persist for up to 2 years, in water - up to 5 years, in frozen meat - a year.

There are 3 known subtypes of the pathogen: bovine, avian and human. Cows and other cattle are susceptible to infection by any of these species. Only the course of the disease differs: in the human type, the symptoms are less pronounced. The causative agent of tuberculosis enters the body through the mucous membrane of the respiratory organs, through the digestive tract. Ways of transmission - aerobic, alimentary, transplacental (intrauterine). List of causes and sources of cattle infection:

1. One individual fell ill in the herd. The causative agent of tuberculosis is released into the external environment with any liquids (urine, feces, sputum).
2. Stalling after a sick individual. The bacterium survives in manure, straw piles, in the soil under the floor.
3. Infection of young animals through colostrum/mother's milk.

Aggravating factors - group crowded content of cattle, unsanitary conditions and dirt in the stalls, lack of normal temperature conditions. Often the cause of infection is a person with tuberculosis in an open form. With an inadequate diet in cows, immune protection is reduced, the risk of developing tuberculosis increases.

You should also pay attention to pastures, they must be equipped for walking cattle.

Symptoms and signs of illness

The duration of the incubation period of tuberculosis in cattle is from 14 days to 6 weeks. Most often, the disease develops latently, the first noticeable symptoms appear several months or even years after infection. Acute leakage is typical only for young animals and calves. Based on the location of the lesion, several types of tuberculosis in cattle are distinguished:

1. Light.
2. Intestines.
3. Uterus.
4. Udder.
5. Generalized view - dispersion of pathogens through the blood, damage to 2 or more systems at the same time.

Specific symptoms for different types of bovine tuberculosis.

1. Severe dry and painful cough.1. Strongly swells, becomes hard, lumpy.

Infected organ	Signs
Lungs	2. Shallow, rapid breathing. 3. Mucous discharge when coughing. 4. Wheezing, moaning are heard. When pressing the area between the ribs, the animal reacts sharply due to severe pain. Infected individuals quickly lose weight, become emaciated.
Udder	2. The supraventricular lymph node is enlarged. 3. Possible wrinkling and deformation of the nipples. 4. Watery colostrum or curd mass with blood clots at milking.
Intestines	Chronic diarrhea. Severe emaciation, weight loss. Pus and blood in the stools.
Uterus, genitals	Male cattle swell, develop orchitis and uveitis. In females - lethargy, fetid green discharge. respiratory dysfunction, intoxication.

Diagnostic measures

The main method of in vivo diagnosis of cattle is tuberculinization. This is an intradermal tuberculin test. Tuberculin is a sterile filtrate of killed bacteria. The procedure is carried out on a regular basis, starting from the age of two months. Frequency - 2 times a year (spring, autumn).

How is cattle diagnosed:

1. Select a place. In bulls, this is the undertail fold, in cows - the middle of the neck, in young animals - the shoulder blades. A small area is cut off, treated with alcohol.
2. Inject 0.2 ml of tuberculin.
3. The animal is left for observation for 3 days.

Based on the information received, the result is established: if a swelling of more than 3 mm appears at the injection site, this is a positive result for tuberculosis. If the temperature of the skin at the injection site has increased and soreness has appeared, this is also a positive result.

In case of an ambiguous reaction, a second test is carried out. Examination after additional procedure is carried out after 24 hours of waiting.

How to treat tuberculosis in cattle

There is no cure for bovine tuberculosis in veterinary practice. It is impossible to cure infected cows. The farm where the disease is recorded is classified as prosperous or dysfunctional. In the second case, quarantine restrictions are imposed on him.

He alth work goes in 2 directions. The first is regular sampling and laboratory tests. The goal is to detect tuberculosis and kill all infected individuals. Checks and rejection of cattle are carried out every 60 days. The second is a complete replacement of the cattle population, including young animals. This direction is applicable if the percentage of infected individuals in the herd exceeds 15. Accompanied by the treatment and disinfection of places of detention - the removal of floor coverings, treatment with formaldehyde and caustic soda. Manure, garbage, inventory, 10-14 cm of the top layer of soil (if the floor is on the ground) are taken out for disposal.

Problem Prevention

Careful prevention is an effective measure to protect cattle from tuberculosis. To develop immunity, the use of the BCG vaccine and tuberculosis toxoid is acceptable. Interval - 10-14 days. But such protection against the disease is characterized by an insufficiently long duration. Therefore, other measures are recommended.

Mandatory preventive actions:

1. Compliance with hygiene norms and standards when keeping, feeding and walking cattle.
2. Registration of animals in veterinary institutions.
3. Compliance with quarantine for new individuals (30 days). Getting them tested by the vet.
4. Careful examination of all livestock at least 2 times a year.
5. Annual x-ray for people who work with cattle.
6. Periodic disinfection of containment areas.

Routes of transmission of tuberculosis from animals to humans

In total, there are 3 ways of transmission of tuberculosis from cattle to humans. Through meat and dairy products, since meat and milk contain many pathogenic bacteria. The risk of infection is present in the absence of proper heat treatment. The next way is contact. Farm workers are at risk: infection occurs when cleaning the barn, as the pathogens are on the bedding of livestock.

The last way is airborne. The animal releases microparticles of mucus and bacteria into the air. Koch's stick remains active for a long time if the barn is hot, humid, and there is no ventilation. Inhaling such air, a person becomes infected with tuberculosis.

Bovine tuberculosis is an incurable disease.Its danger lies in the latent course and the long-term absence of typical symptoms. Cows are susceptible to all types of pathogen, any organ can suffer: from the lungs to the uterus. Tuberculosis is the real reason for the loss of the entire livestock. And only careful prevention, compliance with sanitary standards act as a barrier and protection of cattle from Koch's bacillus.

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