Mycobacterium avium abortion in a sow

A 2-year-old sow aborted her entire near-term litter of 11. Gross and histologic examination of a fetus suggested a tuberculous infection, and a yellow-pigmented Mycobacterium avium serotype 1 was subsequently isolated from the fetal tissue. Efforts to rebreed the sow were unsuccessful. She was anergic to skin tests with purified protein derivative of M. avium on two occasions but had M. avium specific in vitro lymphocyte immunostimulation. Gross granulomatous lesions were found in the liver, kidneys, and endometrium when the sow was necropsied 5 months after the abortion. Histologic examination showed diffuse and focal non-encapsulated granulomas in lymph nodes, tonsils, kidney, liver, spleen, lung, and uterine and vaginal walls. There were a few encapsulated calcified foci in the endometrium. The centers of some granulomas in the tonsils, liver, kidneys, and some lymph nodes were caseated. The yellow-pigmented M. avium was isolated from the reproductive organs and from 11 of 12 other tissues cultured.