Outbreak of abortion associated with Neospora caninum infection in a beef herd

摘要

N. caninum infection was confirmed in 4 fetuses that were aborted by cattle in a 350-head beef herd; an additional 58 cattle aborted during the following 2.5 months. Overall, 44.4% (157/354) of the cattle in the herd did not become pregnant or experienced fetal loss during this period. Initially, 81.3% (282/347) of the herd was seropositive for antibodies to N. caninum, and seropositive cows were 6.2 times as likely not to be pregnant as were seronegative cows. Other potential causes of abortion were not identified. Following the outbreak, few cattle in the herd or in a second exposed herd seroconverted, but high antibody titres persisted in most seropositive cattle until the end of the calving season. Evidence of cow-to-fetus transmission of theorganism was detected in >82% of seropositive cows.