Survey of the prevalence of equid herpesvirus 2 infections

Abstract

Slowly cytopathogenic viruses were isolated from the leucocytes of 17 out of 19 (89 per cent) apparently normal horses, one yearling and one of two foals under two months of age.

The viruses replicated in primary rabbit kidney cells, the RK 13 rabbit kidney cell line and the VERO monkey kidney cell line but not in the BHK 21 hamster kidney cell line.

Typical Cowdry Type A intranuclear inclusions were produced in culture cells and these were shown to contain DNA by acridine orange fluorescence.

Electron microscopy of negatively stained preparations demonstrated characteristic herpesvirus morphology.

The complement fixation reaction demonstrated an antigenic relationship between the viruses isolated and equid herpesvirus 2. Conventional serum neutralisation tests failed to demonstrate neutralising antibody in pooled normal horse serum, pooled normal rabbit serum and reference antisera to equid herpesvirus 1 and 2. Double immunodiffusion gave no reaction.