Pathological Findings on Aborted Fetuses of Dairy Cattle Associated with Neospora-like Protozoa Infection

Neospora-like protozoa were found in the central nervous system (CNS) of 8 aborted fetuses of dairy cattle ranging in fetal age from 143 to 247 days. These abortions occurred in Okayama Prefecture from August 1991 to November 1992. Histological examination of the fetuses revealed multiple focal necrosis and meningitis in CNS, and non-purulent myositis in the heart and skeletal muscles. One fetus of 150 days old had also the organisms in the heart and skeletal muscles. Immunohistochemical examination using antibodies against Toxoplasma gondii, Hammondia hammondi, Neospora caninum, and Sarcocystis crusi was conducted on 4 of the 8 fetusee examined. The Neospora-like organisms positively reacted only with the antibody against Neospora caninum. These results suggested that the 8 fetuses were aborted due to the infection of Neospora like organism.