The detection and phylogenetic analysis of equine herpesviruses 1, 4 and 5 identified in nasal swab samples of asymptomatic horses from Serbia and Bosnia and Herzegovina

Abstract

Nasal swabs originating from 112 apparently clinically healthy and unvaccinated horses of different age, breed and from diverse rearing conditions from Serbia and Bosnia and Herzegovina were examined for the presence of equine herpesviruses 1, 4 and 5 using multiplex nested PCR (Mn‑PCR) and virus isolation. The detected viruses were subsequently characterised by gB gene nucleotide sequencing and their phylogenetic analysis was performed. The infections with EHV‑1, EHV‑4, and EHV‑5 in the examined horse populations are apparently chronic, subclinical and persistent, whilst the shedding of EHV‑1 and EHV‑5 was confirmed by their successful isolation. A connection was established between the finding of EHVs and rearing conditions since horses kept together in stables were positive for at least one EHV in contrast to animals held free grazing or individually. EHV‑5 was found most often in younger horses, however descending in frequency in animals up to 10 years of age. The phylogenetic analysis showed that the identified EHV strains group mostly with Turkish and German strains of respective viruses. A certain degree of genetic heterogeneity was determined regarding the identified EHV‑5 strains in contrast to EHV‑1 and EHV‑4.