[Morphologic and virologic studies of the fetus and placenta in neorickettsial abortion in cattle].

A total of 19 fetuses and 10 placentas were studied. Four fetuses and one placenta harboured neorickettsiae, and the remaining fetuses and placentae originated from cows in the serum of which there were complement-fixing antibodies. These ranged within 1:8-1:64. The gross lesions of the fetuses consisted in the presence of edema with enlargement of the liver. The changes were more characteristic histologically. The liver, kidney, heart, adrenals, and occasionally the lung and spleen had foci of histiocytes, lymphoid and plasmatic cells, and fibroblasts, sometimes with the presence of sporadic leukcoytes. The presence of such cell elements agglomerated in foci fairly often built up formations of granulomatous character. The focal processes prevailed, however, there were diffuse reactions too. Histologically, there were in the placenta diffuse edemas, hyperemia, single hemorrhages, and multiple necrotic foci. A correlation was established between the serologic, virologic, and morphologic changes which made more feasible the diagnosis in such abortions.