Bovine abortion by Neospora caninum in Uruguay

initial diagnoses

Abstract

The results of the diagnosis of bovine neosporosis performed between April 1999/March 2000 at the DILAVE "Miguel C. Rubino", Montevideo, Uruguay are presented in this work. Five bovine foetuses (4 Holstein and 1 Hereford) as well as 276 bovine serum samples from herds with clinical abortion were studied. The histopathological studies of the five foetuses showed multiple foci of necrosis at the central nervous system, (CNS) and myocarditus with nonsuppurative infiltration, both of which are typical lesions of neosporosis. By the immunohistochemical staining (IHC) parasitic forms were observed in the CNS and myocardium which were positive to Neospora caninum. Serological studies for Neospora caninum were performed by the indirect fluorescence antibody test (IFAT). Sera from herds with clinical abortion were examined and 27.7% of 276 bovine sera were serologically positive. From those herds 54% of the aborted cows were positive for Neospora antibodies while only 6% of the pregnant cows were positive. The seropositivity to Neospora caninum was significantly correlated with abortion by Chi-square test (p<0.01). Only two of the five foetuses were sent together with the dam sera. These two foetuses were positive by the IHC and the sera were also positive with the IFAT titres of 1:12800 and 1:3200. This is the first report of Neospora caninum associated bovine abortion in Uruguay by means of serological and immunohistochemical procedures.