Bovine neosporosis: comparison of serological methods using outbreak sera from a dairy herd in New Zealand

Serological methods developed to detect Neospora caninum specific bovine an tibodies were compared using Sera from an abortion outbreak on a dairy farm in New Zealand. These methods included four ELISAs, IFAT and immunoblot. T he abortions (n = 16) on the farm were restricted to one of two groups of t he herd which consisted of 194 adult dairy cows. All ELISAs, IFAT and immun oblot (applying stringent cut-off levels) revealed a statistically signific ant association between seropositivity and abortion among the adult cows fr om the afflicted group I. The strength of this association varied between d ifferent tests, and different seroprevalences were determined for various a nimal groups. Among the different ELISAs, the strength of the relationship between single test results was characterised by a considerable variation i n the determinants of correlation. Discrepancies in positive-negative class ification between the two commercial ELISAs and one of the in-house ELISAs were due mainly to differences in the cut-off selection. (C) 1999 Australia n Society for Parasitology Inc. Published by Elsevier Science Ltd. All righ ts reserved.