AN ANIMAL-MODEL OF FOCAL, SUBACUTE, VIRAL RETINITIS

To study local intravitreal therapies for retinitis due to herpes viru ses, an animal model of focal, subacute, relatively nonlethal herpes f amily retinitis is needed. Herpes simplex virus type 1 (HSV-1) was inj ected into the subretinal space of 33 Dutch pigmented rabbit eyes. The animals were observed for up to 42 days after the inoculation. All in oculated eyes developed a focal, enlarging area of retinitis in a pred ictable manner, showing focal enlarging areas of retinal opacification and necrosis with variable retinal hemorrhage. In the inoculated eyes , retinal detachment developed in all animals within 21 days; 33% of t he animals developed focal retinitis in the uninoculated eye. Histolog ic examination showed encephalitis to be present in 11 (73%) of the 15 animals studied after 1 week. This model may be used to evaluate the therapeutic efficacy of new antiviral agents and modalities in the tre atment of herpes family viral retinitis. The model is most similar to herpes simplex or zoster retinitis in humans, but also shares some sim ilarities (and differences) with cytomegalovirus (CMV) retinitis in hu mans.