Molecular characteristics and pathogenicity of an equid alphaherpesvirus 1 strain isolated in China.

Equid alphaherpesvirus 1 (EHV-1) is prevalent in China, and causes notable economic damage to the equine industry. However, there is no information regarding the molecular characteristics and pathogenicity of the Chinese strains. Therefore, an EHV-1 strain, named YM2019, was isolated from the lung tissue of an aborted horse fetus in Xinjiang, China, and its genome and pathogenicity were analyzed. The full genome of the isolate was 150,267 base pairs in length, with 56.7% G + C content. Genetic and phylogenetic analysis showed that strain YM2019 (GenBank: MT063054) belonged to the ORF30 N752 genotype but displayed a high level of similarity with strain Ab4 (ORF30 D752, GenBank: AY665713) isolated in Britain. Fourteen unique amino acid mutations were found when comparing strain YM2019 with the reference strains Ab4 and V592 (ORF30 N752, GenBank: AY464052). Syrian hamsters infected with strain YM2019 exhibited severe respiratory and neurological clinical signs and died. Infection with strain YM2019 in Yili horses caused rhinopneumonitis, viremia, and neurological clinical signs such as hind limb lameness, prostration, and reduced movement. Here, we describe the features of an EHV-1 strain discovered in China, together with the complete genome sequence, and reveal that a nonneurovirulent strain (ORF30 N752) can also cause neurological signs in horses. The data will be useful in providing some reference for further research into the relationship between viral genotypes and pathogenicity.