Neuropathogenicity of Equine Herpesvirus 9 in Cattle

The pathogenicity of equine herpesvirus 9 (EHV-9), a neurotropic equine herpesvirus isolated from a herd of Gazella thomsoni, was studied in cattle. Seven calves were inoculated intranasally with 105 and 107 plaque-forming units of the EHV-9 P19. Three animals showed brain lesions consisting of glial reactions and perivascular cuffings in the olfactory bulb and the frontal and temporal lobes. Additionally, the animal that was inoculated with 107 plaque-forming units showed neuronal degeneration and loss, as well as nuclear inclusions compatible with herpesvirus. EHV-9 was isolated from the brain of calf 6 and the lungs of calves 1 and 2. The results suggested that cattle are susceptible to experimental infection with EHV-9 and at risk from natural infection from reservoir hosts.