To determine whether Neospora caninum, a parasite known to cause repeated a
bortions and stillbirths in cattle, also causes repeated abortions in human
s, we retrospectively examined serum samples of 76 women with a history of
abortions for evidence of N, caninum infection. No antibodies to the parasi
te were detected by enzyme-linked immunosorbent assay, immunofluorescence a
ssay, or Western blot.