Neuronal propagation of HSV1 from the oral mucosa to the eye

PURPOSE. To identify possible neuronal pathways leading to herpetic ocular disease after primary oral infection in mice. METHODS. The SC16 strain of herpes simplex virus (HSV)-1 (10(6) plaque-form ing units) was injected into the mucocutaneous border of the left upper lip . Animals were killed 2 to 10 days postinoculation (DPI). Spread of the vir us in neural structures was studied by immunochemistry. RESULTS. HSV1 first replicated at the site of inoculation and then at the s uperior cervical ganglion (at 2 DPI). The trigeminal ganglion and the facia l nerve fibers were infected by 4 DPI. Infection of the ciliary body and ir is occurred at 6 DPI, together with several brain stem nuclei belonging to the autonomic or sensory pathways. Between 8 and 10 DPI, the neural infecti on gradually cleared up, except for the ipsilateral sympathetic ganglion, a nd ipsilateral keratitis appeared in some animals. CONCLUSIONS. The pattern of viral dissemination in this mouse model suggest s that infection of iris and ciliary body results from transfer of virus in the superior cervical ganglion from sympathetic neurons innervating the li p to neighboring neurons innervating the anterior uvea. Later, zosteriform spread of virus from the trigeminal system may have contributed to the clin ical and histologic findings.