APPLICATION OF AN EQUINE HERPESVIRUS-1 (EHV1) TYPE-SPECIFIC ELISA TO THE MANAGEMENT OF AN OUTBREAK OF EHV1 ABORTION

Sera from 33 Australian thoroughbred mares were tested during an outbr eak of equine herpesvirus 1 (EHV1) abortion with an enzyme-linked immu nosorbant assay (ELISA) for the presence of EHV1-specific antibodies. The ELISA used a recombinant EHV1 antigen derived from glycoprotein G (gG) and distinguished antibodies to EHV1 from those of the antigenica lly related and widespread herpesvirus EHV4. Sera were obtained from m ost of the mares on three occasions, three, 13 and 67 days after the f irst abortion. Mares which were negative in the ELISA were kept separa te from mares which were positive. A second abortion occurred two days after the first and two more abortions and one perinatal death occurr ed later, Sera from these last three mares showed a significant increa se in EHV1-specific antibody on day 13 indicating a recent infection w ith EHV1. Ten other mares did not have antibodies to EHV1 on day 13 bu t had seroconverted to EHV1 by day 67. Despite the EHV1 infection, the se mares foaled normally, possibly because the infection had occurred either late in gestation or after foaling. Seven mares that remained n egative in the ELISA throughout the testing period did not abort, and neither did 11 mares that were positive in the ELISA when they were fi rst tested.