Peculiarities of epizootological surveillance and control of mycobacteriosis in productive animals in the conditions of dairy farms of Ukraine

Abstract

The increase in mycobacteriosis, an infectious disease caused by non-tuberculous mycobacteriosis, has become an urgent issue for humane medicine. The mycobacteriosis of animals is a subject of intense study by veterinary scientists across most countries globally. In Ukraine, the number of farms with productive animals exhibiting paraallergic reactions to tuberculin is steadily rising, making the diagnosis of tuberculosis more complicated. In dairy cattle breeding, this issue also has significant economic implications. The forced slaughter of breeding young stock and high-producing cows is often a consequence. On the other hand, the identification of various non-tuberculous mycobacteria species in human mycobacteriosis patients, which can sensitize the cows, gives the issue of preventing animal mycobacteriosis both medical and social significance. All of the factors mentioned previously led to the decision to permanently retain cows that react positively to tuberculin testing on a dairy farm in the Volyn region, which has historically been free of tuberculosis. A comprehensive study was conducted from 2018 to 2023, utilizing methods of epizootological analysis as well as clinical, pathological, histological, bacteriological, and statistical research techniques. It was shown that an epizootic process, caused by the infection of cattle with non-tuberculosis mycobacteria, is occurring on the dairy farm. Mycobacterium scrofulaceum, M. fortuitum, and Nocardia spp. were isolated and identified from the lymph nodes and lymphoid tissue of the large intestine submucosa in the infected animals. These pathogens cause significant histological and pathological changes, indicating the presence of a clinically covert infectious process accompanied by sensitization of the animal organism. Epizootological analysis of the results from simultaneous allergic testing, as well as multiple bacteriological studies of samples from animals that reacted positively to both purified protein derivate tuberculin and atypical mycobacteria allergens, established that the allergic reactions to tuberculin were paraallergic in nature. This indicated the presence of an active infectious process within the animals’ bodies.