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


METHODS
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.


RESULTS
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).


CONCLUSIONS
Excimer laser keratectomy appears to be an efficient trigger for the reactivation of latent HSV-1 in the New Zealand rabbit ocular model.
Dhaliwal
D K
DK
Department of Ophthalmology, University of Pittsburgh Medical Center, Pennsylvania, USA.
Barnhorst
D A
DA
Romanowski
E
E
Rehkopf
P G
PG
Gordon
Y J
YJ
D000818:Animals; D002522:Chlorocebus aethiops; D003315:Cornea / Q000601:surgery / Q000821:virology*; D004195:Disease Models, Animal; D005260:Female; D018259:Herpesvirus 1, Human / Q000302:isolation & purification / Q000502:physiology*; D007635:Keratitis, Dendritic / Q000601:surgery / Q000821:virology*; D054018:Lasers, Excimer; D018903:Photorefractive Keratectomy; D011817:Rabbits; D014709:Vero Cells / Q000821:virology; D014775:Virus Activation; D014776:Virus Cultivation / Q000379:methods; D017735:Virus Latency / Q000502:physiology*