An atypical clinical presentation for the first isolation of Canid herpesvirus 1 in Argentina

Evaluation of topical ophthalmic ganciclovir gel for the treatment of dogs with experimentally induced ocular canine herpesvirus-1 infection

OBJECTIVE To determine the in vitro half maximal effective concentration (EC₅₀) of ganciclovir for canine herpesvirus-1 (CHV-1) and to evaluate the efficacy of ganciclovir ophthalmic gel in dogs with experimentally induced ocular CHV-1 infection. ANIMALS 10 specific pathogen-free adult Beagles. PROCEDURES Cytotoxicity and EC₅₀ of ganciclovir for CHV-1 were determined during in vitro experiments. During an in vivo experiment, dogs with experimentally induced ocular CHV-1 infections received 1 drop of 0.15% ganciclovir (ganciclovir group; n = 5) or artificial tear (control group; 5) ophthalmic gel in both eyes 5 times daily for 7 days, then 3 times daily for 7 days. For each dog, ophthalmic and confocal microscopic examinations were performed at predetermined times to determine severity of ocular disease and inflammation. Conjunctival swab specimens were collected at predetermined times for PCR assay analysis to determine CHV-1 shedding. RESULTS No in vitro cytotoxic effects were observed for ganciclovir concentrations ≤ 500μM. The EC₅₀ of ganciclovir for CHV-1 was 37.7μM. No adverse effects associated with ganciclovir were observed during the in vivo experiment. Mean ocular disease and inflammation scores for the ganciclovir group were significantly lower than those for the control group. Mean duration of CHV-1 shedding for the ganciclovir group (0.4 days) was significantly shorter than that for the control group (6.2 days). CONCLUSIONS AND CLINICAL RELEVANCE Topical administration of 0.15% ganciclovir ophthalmic gel was well tolerated and effective in decreasing clinical disease scores, ocular tissue inflammation, and duration of viral shedding in dogs with experimentally induced ocular CHV-1 infection.

Canine herpesvirus-1 ocular diseases of mature dogs

Canine herpesvirus-1 (CHV-1) is an alphaherpesvirus with a host range restricted to canids. Latent CHV-1 infection is endemic in domestic dog populations worldwide. The role of CHV-1 in severe systemic neonatal infections and as an aetiology of infectious infertility and abortion has been appreciated for decades; however, ocular diseases of mature dogs conclusively associated with CHV-1 infection were only recently described. Clinically, CHV-1 infection may produce a diverse range of adnexal and ocular surface lesions in mature dogs, including blepharitis, conjunctivitis, ulcerative keratitis, and nonulcerative keratitis. These conditions can develop during primary or recurrent ocular CHV-1 infection. Recurrent CHV-1 infections associated with reactivation of latent virus may be observed during a variety of situations and in association with numerous different viral reactivation stimuli, including the administration of immunosuppressive pharmaceuticals. The understanding of CHV-1 pathophysiology and ocular infections in mature dogs has expanded rapidly during the past few years, but much remains to be elucidated. As the number of dogs living with chronic immunomodulatory systemic diseases and receiving immunosuppressive therapeutics continues to grow, the clinical importance of CHV-1 ocular infections is also likely to increase.

Canine reproductive, respiratory, and ocular diseases due to canine herpesvirus

This review documents how clinical inquiry expands as our knowledge base about canine herpesvirus (CHV) increases. We must understand the various forms of CHV infection that may occur in the dog population. This has prompted the veterinary community to develop more sensitive diagnostic assays. CHV is more common than we considered a decade ago. Up to 70% of some high-risk dog populations have been infected with and are latent carriers of CHV. Recognition of the various forms of CHV-induced disease, availability of diagnostic assays with increased sensitivity, and the formation of reliable biosecurity measures will allow for better control steps.