Acute and recurrent infection with herpes simplex virus in the mouse: a model for studying latency and recurrent disease.

Nineteen recent isolated and three laboratory strains of herpes simplex virus types 1 and 2 were tested for their ability to produce clinical signs in mice following intradermal inoculation in the ear. All viruses produced erythema at the inoculation site; this was the most sensitive clinical sign of infection. Virus multiplication in the ear tissue was similar for both types 1 and 2 up to the fifth day after inoculation but type 2 viruses persisted for longer. Latent infection was demonstrated in cervical dorsal root ganglia. Type 1 viruses required a much higher dose than type 2 to produce neurological signs and death after intradermal inoculation but the difference was less after intracerebral inoculation. Erythema of the inoculated ear recurred sporadically during several months observation in about half the mice that survived intradermal infection with a selected type 1 isolate. The presence of virus in the ear tissue during such recurrences was confirmed by electron microscopy and isolation of infectious virus. The system of ear infection in the mouse is presented as a new model for studying neurovirulence, and latent and recurrent infection with herpes simplex virus.