Transplacental transmission of tuberculosis infection in cows infected with Mycobacterium bovis

Abstract

A culture of M. bovis was isolated from liver and spleen homogenate, from tissues and amniotic fluid of 8- and 6-month-old fetuses of cows with local tuberculous changes in the lymph nodes of the lungs. It serves as confirmation of the transplacental infection transmission. The transfer occurred due to filtering virus-like forms of tuberculosis mycobacteria, which were transformed into non-acid-fast, partially acid-fast and typical forms of tuberculosis mycobacteria in tissues, which can lead to the emergence of endogenous tuberculosis after birth or create an invisible reservoir of infection, because non-acid-fast forms of mycobacterium do not induce the development of hypersensitivity to tuberculin. In addition, the persistence of modified and typical mycobacteria in fetuses can lead to immunological tolerance to their antigens.

The results obtained confirm the correctness of the regulations on the isolated rearing of calves born in disadvantaged conditions, followed by fattening and delivery for slaughter.