Effect of a single point mutation on equine herpes virus 9 (EHV-9)neuropathogenicity after intranasal inoculation in a hamster model

[摘要] This study aimed to investigate the neuropathogenesis of equine herpes virus 9 (EHV-9) bystudying the effects of a single point mutation introduced in two different EHV-9 genes.The two EHV-9 mutants, 14R and 19R, were generated carrying a point mutation in twoseparate EHV-9 genes. These mutants, along with the wild-type EHV-9, were used to infect ahamster model. The EHV-9- and 19R-infected groups showed earlier and more severe clinicalsigns of infection than the 14R-infected group. The white blood cells (WBCs) count wassignificantly increased in both EHV-9- and 19R-infected groups compared to the14R-infected group at the 4th day post infection (DPI). Viremia was also detected earlierin both EHV-9- and 19R-infected groups than 14R-infected group. There were differences inthe anterograde transmission pattern of both EHV-9 and 19R compared to 14R inside thebrain. Serum TNF-α, IL-6 and IFN-γ levels were significantly increased in both EHV-9- and19R-infected groups compared to the 14R-infected group. Histopathological andimmunohistochemical analyses revealed that the mean group scores for the entire brain weresignificantly higher in both EHV-9- and 19R- infected groups than 14R-infected group.Collectively, these results confirm that the gene product of Open Reading Frame 19 (ORF19)plays an important role in EHV-9 neuropathogenicity and that the mutation in ORF19 isresponsible for the attenuation of EHV-9.

[学科分类] 兽医学

[关键词] 14R;19R;EHV-9;hamster;neuropathogenicity