Frequency of spontaneous canine herpesvirus-1 reactivation and ocular viral shedding in latently infected dogs and canine herpesvirus-1 reactivation and ocular viral shedding induced by topical administration of cyclosporine and systemic administration of corticosteroids.
OBJECTIVE
To determine the frequency of spontaneous canine herpesvirus-1 (CHV-1) reactivation and ocular viral shedding in latently infected dogs and the effect of topical ocular administration of cyclosporine.


METHODS
8 mature Beagles with experimentally induced latent CHV-1 infection.


METHODS
Following induction of primary ocular CHV-1 infection, the presence of reactivatable CHV-1 latency was confirmed by systemically administering prednisolone to the dogs. Dogs were then monitored for 36 weeks via clinical examination and conjunctival sample CHV-1 PCR assay performed at 4-day intervals and CHV-1 virus neutralization antibody assay performed at 2-week intervals. During weeks 16 to 32, dogs were administered 0.2% cyclosporine ointment in both eyes twice daily and blood cyclosporine concentrations were monitored. During weeks 33 to 36, the presence of reactivatable CHV-1 latency was reconfirmed via systemic administration of prednisolone.


RESULTS
Reactivation of latent CHV-1 was not detected via clinical examination or viral shedding during the initial 32 weeks, including before and during topical ocular administration of cyclosporine, and there were no significant differences in CHV-1 virus neutralization titer increases between the study periods. Blood cyclosporine concentrations were less than assay detection limits in all dogs on the sampling days. Systemic administration of corticosteroids repeatedly resulted in ocular disease and viral shedding.


CONCLUSIONS
Spontaneous CHV-1 reactivation did not occur frequently in latently infected mature dogs, and this was not altered by topical ocular administration of cyclosporine. This characteristic may be a factor contributing to the lower frequency of recurrent herpetic ocular disease in dogs relative to other host species and their associated alphaherpesviruses.
Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA. ecl32@cornell.edu
Eric C
EC
Ledbetter
Erotides C
EC
da Silva
Sung G
SG
Kim
Edward J
EJ
Dubovi
Wayne S
WS
Schwark
D060433:Administration, Ophthalmic; D000305:Adrenal Cortex Hormones / Q000008:administration & dosage; D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D016572:Cyclosporine / Q000008:administration & dosage* / Q000097:blood; D004279:DNA, Viral / Q000737:chemistry / Q000235:genetics; D004283:Dog Diseases / Q000188:drug therapy / Q000821:virology*; D004285:Dogs; D005128:Eye Diseases / Q000188:drug therapy / Q000662:veterinary* / Q000821:virology; D006566:Herpesviridae Infections / Q000188:drug therapy / Q000662:veterinary* / Q000821:virology; D002184:Herpesvirus 1, Canid / Q000235:genetics / Q000276:immunology / Q000502:physiology*; D007166:Immunosuppressive Agents / Q000008:administration & dosage* / Q000097:blood; D008297:Male; D009500:Neutralization Tests / Q000662:veterinary; D016133:Polymerase Chain Reaction / Q000662:veterinary; D017735:Virus Latency
D000305:Adrenal Cortex Hormones; D000914:Antibodies, Viral; D004279:DNA, Viral; D007166:Immunosuppressive Agents; D016572:Cyclosporine