Paratuberculosis in animals: identification and control

Paratuberculosis of domestic animals is common in many countries of the world, as evidenced by numerous data from foreign literature. 

According to the OIE, paratuberculosis is registered in 61 countries of the world, including RUSSIA.

Paratuberculosis (paratuberculosis) (paratuberculous enteritis, Johne's disease ) is an infectious chronic disease leading to exhaustion and death of animals, characterized by diffuse thickening of the intestinal mucosa and submucosa with the formation of transverse and longitudinal folds, accompanied by impaired absorption function. 

The causative agent of paratuberculosis is Mycobacterium paratuberculosis. it is a thin, polymorphic, gram-positive, immobile rod 0.5-1.5 µm long and 0.2-0.5 µm wide, does not form spores, grows under aerobic conditions, acid-alcohol-resistant, stains well according to Ziehl-Neelsen ruby red color.

Cattle , sheep, goats, wild ruminants, deer are susceptible to the pathogen ; among laboratory animals, rabbits, hamsters and white mice are susceptible when infected intravenously. Horses and pigs can be bacteria carriers.

The main source of the causative agent of paratuberculosis are clinically and latently sick animals, which excrete a huge amount of mycobacteria in their feces, abundantly infecting watering places, pastures, feed, bedding, premises and other environmental objects, which are factors in the transmission of infection.

Mostly young animals under the age of 6 months are infected through contaminated feed and water, as well as through udder teats contaminated with mycobacteria, when drinking contaminated MILK, interspecific transmission is also possible.

The incubation period of this disease lasts for months and even years. There are latent (latent form) and open (clinical form) course of the disease.

There is no effective diagnostic tool for identifying latently sick animals yet. For intravital diagnosis, bacterioscopic, allergic (avian tuberculin or paratuberculin is administered and, as in tuberculinization, the result of an allergy test is taken into account) and serological (RSC) methods.

Economic damage is determined by a decrease in the productivity of sick animals (MEAT, dairy, wool), forced slaughter of clinically ill animals, as well as significant costs associated with diagnostic studies and restrictive measures.

Since paratuberculosis is introduced into farms with latently diseased animals, it is necessary to pay special attention to ensuring that the recruitment of herds and the import of livestock is carried out only from farms that are free from paratuberculosis. To prevent the disease, it is necessary to comply with zoohygienic requirements for keeping and feeding animals. It is necessary to conduct a thorough examination of the intestines after the slaughter of animals entering the meat processing plant in order to timely detect diseases and take measures to limit unfavorable areas.

If paratuberculosis is diagnosed on a farm, restrictions are imposed on the farm. It is necessary to promptly identify all clinically sick animals and hand them over for slaughter.

Carry out an allergy test and RSK with mandatory double-checking to identify latently sick animals. The milk is pasteurized or boiled, after which it is fed to the young animals. Manure is burned or subjected to biothermal disinfection for 2 years. In dysfunctional households, the premises are thoroughly disinfected. Restrictions are lifted from the farm if it receives negative test results with avian tuberculin or negative tests at the Distribution Center within a year.