Prevalence of asinine herpesvirus type 5 (AsHV-5) infection in clinically normal Lipizzaner horses

The aim of this study was to assess the extent of asinine herpesvirus (AsHV) type 5 infection in ‘closed’ populations of clinically normal Lipizzaner horses. Peripheral blood mononuclear cells plus nasal and conjunctival swabs were obtained on four occasions over an 18 month period from 266 animals as part of a health surveillance programme. Sequence analysis of samples that were positive by nested consensus herpesvirus PCR but negative using quantified equid herpesvirus (EHV) type 2 and 5 PCR, revealed a total of 51 samples from 39 horses positive for AsHV-5. No statistically significant association between animal age, gender or geographical location and infection status was identified. The findings suggest sub-clinical AsHV-5 infection may be encountered more frequently than previously reported.