Spontaneous ocular shedding of HSV-1 in latently infected rabbits

Abstract

The unscarified corneas of rabbits were inoculated with 50 microliter of 2-4 X 10(6) PFU/ml of herpes simplex virus, type 1 (HSV-1), McKrae strain in 10 separate experiments over a 12-month period. Sixty of 104 (57.7%) rabbits survived to postinoculation (PI) day 20. These sixty rabbits were swabbed with dacron-tipped swabs for twenty consecutive days (PI days 20-39). The tear film collected on the swabs was immediately placed in tissue culture tubes with confluent primary rabbit kidney (RK) cell monolayers. The RK monolayers were monitored for cytopathic effects indicative of HSV-1. Fifty-eight of the sixty rabbits (96.7%) inoculated had at least one positive episode. Ninety-three of the 120 eyes (77.5%) of the latently infected rabbits had at least one positive episode. Virus was detected in 72 of the 93 positive eyes (77.4%) between PI days 20 and 29 and in 21 of the 93 positive eyes (22.5%) between PI days 31-39. A total of 2400 swabs were taken and 324 were positive (13.5%). All of the 58 positive rabbits were used later for ocular induction of HSV-1 and all 116 eyes of the latently infected rabbits shed virus for at least four consecutive days during induction.