The pathogenesis of herpetic ocular disease in the guinea pig

A detailed study of the pathogenesis of herpetic eye disease in the guinea pig was undertaken to further develop this animal model. Several well-known HSV-1 strains were tested for their ability to produce disease and cause acute and latent infections of the trigeminal ganglion: McKrae, KOS, McIntyre, RE, and Shealey. Two HSV-2 strains failed to cause eye infections. The Shealey strain [HSV-1 (Sh)] produced the most severe eye infections, characterized by epithelial and stromal disease, corneal vascularization and ulcerative blepharitis. Consequently, HSV-1 (Sh) was selected as the prototype strain for this study. The frequency and severity of HSV-1 (Sh) eye disease patterns was determined by a semi-quantitative rating scale, which permitted accurate monitoring of the temporal development of the disease patterns cited above. Virus shedding from infected eyes was also quantified. All of the HSV-1 strains tested established trigeminal ganglionic latency with varying frequency, although HSV-1 (Sh) latency approached 100 percent. The kinetics of acute ganglionic infection by HSV-1 (Sh) was determined, and peak virus titers occurred on the third day after corneal inoculation. This study emphasizes the usefulness of the Guinea pig model for investigations on the pathogenesis, prevention and treatment of herpetic eye infections.