Herpes simplex encephalitis. Immunohistological demonstration of spread of virus via olfactory and trigeminal pathways after infection of facial skin in mice.

An immunohistological study of viral antigen (VA) in the brain was carried out in mice which had been infected with herpes simplex type 1 virus (HSV) in the skin of the face. In 77% of the mice with VA in the brain the olfactory system as well as the trigeminal system/brainstem was affected. The remaining 23% had VA in the trigeminal system/brainstem only. Eye swab cultures yielded HSV from all mice with VA in the olfactory system. The ease of access of virus infecting the face to the olfactory system shown in this model may have implications for human infections.