Genomic and antigenic comparison of an equine herpesvirus 1 (EHV 1) isolate from the 1983 Lippizan abortion storm with EHV 1 reference strains.

An EHV 1 isolate from the Lippizan Stud at Piber, which caused the abortion and paresis outbreak in 1983, was investigated using 3 known subtype 1 and 2 subtype 2 strains for comparison. Broad-scale restriction enzyme analysis as well as cross-neutralization with hyperimmune sera produced in rabbits were performed, and SDS-PAGE of infected cell proteins was conducted on a limited scale. The Piber isolate was clearly classified as a subtype 1 strain of EHV 1, and showed closest resemblance in its restriction patterns with a British EHV 1 strain, which originated from an outbreak with paretic symptoms. A second Piber isolate from the same outbreak examined to limited extent only was practically indistinguishable from the first one, as could have been expected. A thoroughly controlled systematic vaccination program with existing commercial vaccines against EHV 1 should protect the endangered Lippizan horses population against the abortigenic and less certainly against the paretic syndromes caused by this virus. According to data presented, a protection against respiratory disease is less probable.