BOVINE FETAL NEOSPOROSIS - A COMPARISON OF EPIZOOTIC AND SPORADIC ABORTION CASES AND DIFFERENT AGE CLASSES WITH REGARD TO LESION SEVERITY AND IMMUNOHISTOCHEMICAL IDENTIFICATION OF ORGANISMS IN BRAIN, HEART, AND LIVER

Eighty bovine fetuses with confirmed neosporosis were used to score le sion severity and presence of parasites in brain, heart, and liver. A comparison was made between epizootic and sporadic abortion cases. The possible influence of fetal age was also investigated. Histologic les ions of multifocal encephalitis, myocarditis, and periportal hepatitis with or without focal hepatocellular necrosis were almost always obse rved. Neospora caninum tachyzoites were identified immunohistochemical ly in 85% of the brains, 14% of the hearts, and 26% of the livers. Tis sue cysts were observed in 21% of the brains. Significant differences between epizootic and sporadic abortion cases were found only in the l iver. Hepatic lesions were more prominent and N. caninum tachyzoites w ere observed more frequently and in higher numbers in epizootic cases. Examination by immunohistochemistry of the liver in addition to the b rain can be highly contributive diagnostically, particularly in epizoo tic cases. There were no significant age-related differences except fo r a higher presence of tachyzoites in the hearts of younger fetuses (3 -4 months gestational age).