Characteristics and epidemiological investigation of equid herpesvirus 8 in donkeys in Shandong, China

Equid herpesvirus 8 (EHV-8), also known as asinine herpesvirus type 3 (AHV-3), can cause severe respiratory disease, abortion in mares, and neurological disorders. There is limited information on the prevalence of EHV-8 in donkeys in China. In this study, we investigated EHV-8 infection in donkeys using PCR, resulting in the identification of a field strain, termed EHV-8 SD2020113, which was isolated using RK-13 cells and characterized by high-throughput sequencing and transmission electron microscopy. Our data indicated that 38.7% (457/1180) of donkeys showed the presence of EHV-8 in blood samples. Analysis of the ORF70 gene showed the highest similarity (99.8-99.9% identity) to EHV-8 IR/2015/40 (MF431614.1) and SDLC66 (MW816102), and, in phylogenetic analysis, it clustered with EHV-8 SDLC66 from China. The findings of this study indicate that EHV-8 is likely to represent a threat to the donkey industry, and breeders and veterinarians who care for donkey farms should be aware of this.