Opportunistic infections in animals: spread causes and preventive measures

Industrial animal husbandry faces the acute problem of maintaining animal health, including the prevention of infectious aggression. At the same time, the intensification of production, inevitably associated with the action of a large number of stress factors on animals, contributes to a decrease in the resistance of the livestock and an increase in the risk of developing infectious diseases, including the spread of opportunistic infections, which are often combined. This leads to a violation of several mechanisms of anti-infective protection and reduces resistance to less pathogenic microorganisms. The most common opportunistic infections in pigs are colibacillosis, pasteurellosis, salmonellosis, dysentery, mycoplasmosis (enzootic pneumonia), hemophilic polyserositis, enterococcal infection (streptococcosis), actinobacillary pleuropneumonia, etc., which are most often clinically manifested as associated viral-bacterial infections. Opportunistic infections are characterized by polynosology and polyetiology, they can occur latently, but as immunosuppression increases, they acquire dangerous forms of the course with atypical clinical manifestations or disseminated lesions. The damage caused by opportunistic infections to productive livestock is due to a decrease in productivity and reproductive function, as well as culling and death of animals. In order to limit the spread of infectious diseases (not only opportunistic ones) and minimize the use of antibacterial drugs, it is necessary to improve the protocols for vaccination and the use of antibiotics, and it is also necessary to develop a scientifically based methodology for increasing the resistance of animals (including the use of immunomodulators). At the same time, an obligatory element of complex measures is the creation and maintenance of optimal zootechnical and zoohygienic conditions for keeping animals, especially in the conditions of large livestock complexes.