Efficient reactivation of latent herpes simplex virus type 1 infection by excimer laser keratectomy in the experimental rabbit ocular model

Abstract

To investigate the role of excimer laser keratectomy as a trigger for the reactivation of latent HSV type 1 (HSV-1) in the New Zealand rabbit ocular model. There are conflicting reports in the current literature about reactivation of HSV-1 after excimer laser photoablation. New Zealand rabbits were inoculated topically with HSV-1 McKrae or W strain in each eye, and culture-positive dendritic keratitis was documented on day 7. After the establishment of latency (21+ days), animals were divided into three groups: group I animals underwent excimer laser photoablation in each eye; group II animals received intrastromal injections of sterile water to act as positive controls (a standard method); and group III animals received no treatment and represented spontaneous shedders. All eyes were swabbed daily from days 1 through 10 and plated on A549 cells. Recovery of HSV-1 on days 1 through 10 postinduction was analyzed to compare the efficiency of the different methods of viral reactivation. Reactivation of latent HSV-1 after excimer treatment was observed in nine (45%) of 20 eyes and was equivalent to the rate of reactivation seen in the positive control animals (eight [44.4%] of 18 eyes) (P =.99). Both of these rates were significantly greater than those of the untreated animals (one [5.6%] of 18 eyes) (P =.018). Excimer laser keratectomy appears to be an efficient trigger for the reactivation of latent HSV-1 in the New Zealand rabbit ocular model.