Four pregnant mares were inoculated intranasally and/or intravenously with equine herpesvirus 1 (EHV-1), subtype 1 during the third trimester of gestation. The pathology associated with EHV-1-induced neurological disease includes vasculitis of the small blood vessels within the central nervous system and subsequent damage to the surrounding neural tissue. In addition, SPv could be distinguished on the basis of its pathogenicity in baby mice inoculated intracerebrally. Telford, M. Further analysis of these T-cell populations revealed identical EHV-1-specific cytotoxic T-lymphocyte responses. A marked reduction of virus release was observed although no significant influence was noticed either on plaque size or on the syncytial phenotype of the EHV-1 strain RacH. From days 1 to 3 p.i., cell-associated viremia was occurred in NHH1-infected mice, but not in HH1-infected mice.
The detection rate of the sequence-capture PCR method for EHV-1 latency was double that of conventional nested or realtime PCR assays performed on the same MLN DNA preparations. The number of viral antigen-positive cells increased markedly after day 5 p.i. In contrast, no viral antigen-positive cell was detected in the CNS in HH1-infected mice, except for a few nerve cells in the thoracic cord on day 4 p.i. These results suggest that NHH1 neuroinvasion is hematogenous and is correlated with enhanced extraneural virus growth.