An animal model of ocular herpes. Keratitis, retinitis and cataract in the mouse

Acute ocular infection followed both intracerebral and intranasal inoculation of herpes simplex type I virus (HSVI) in mice. Eye infections were a terminal complication of fatal encephalitis. After intracerebral inoculation HSVI spread directly along the optic nerves to infect the retina provoking a necrotizing retinitis. In contrast after intranasal inoculation, HSVI spread via the fifth cranial nerve to the anterior chamber of the eye producing keratitis and uveitis. Necrotizing retinitis was also produced by intracerebral inoculation of mice with a drug-resistant mutant HSVI known to have relatively low neurovirulence. These animals developed only mild encephalitis but this was associated with florid retinitis. The mice survived cerebral infection with the mutant virus and several weeks after initial inoculation cataracts were observed. There was no evidence, at any time, of virus infection of lens epithelium and cataracts appeared to be a non-specific consequence of retinal injury. It is suggested that these examples of murine ocular infection provide animal models for herpetic eye lesions in man and thus may elucidate the pathogenesis of herpetic keratitis, retinitis and cataract.