Neospora caninum has recently attracted considerable attention globally as an abortifacient agent in cattle. Despite the high incidence of suspect protozoal abortion reported by veterinary pathologists in Queensland, little work has been conducted on the distribution and prevalence of N. caninum in Queensland cattle. A seroepidemiological survey was performed on dairy and beef herds from three production districts; northern, central and southeastern Queensland. Five serological tests were evaluated against a range of reference sera to determine their efficacy: three enzyme-linked immimoassays (ELISA), a modified agglutination test (MAT) and an indirect fluorescent antibody test (IFAT). The MAT yielded poor sensitivity, while the IDEXX ELISA and the IFAT gave comparable results. The IDEXX ELISA was chosen for the survey as it gives an objective result and is less time consuming. Serum samples were collected from a total of 1,140 cattle. The seroprevalence of N. caninum was 27.8% (ranging from 17-41% between herds) in dairy cattle and 6% in beef cattle. Analysis of herd records revealed that approximately 11% of gestations in seropositive animals ended in abortion, compared to approximately 3% for seronegative animals. Longitudinal studies conducted …… No statistically significant differences in seroprevalence were found due to the origin, sex or age of the dogs.
Attempts were made to isolate a Queensland strain of N. caninum from naturally infected cattle. Eight attempts were made to establish in vitro isolates, but none were successful.