Experimental primary ocular canine herpesvirus-1 infection in adult dogs

Abstract

Objective - To characterize clinical ocular disease, viral shedding, and serologic response associated with primary canine herpesvirus-1 (CHV-1) ocular infection in naïve adult dogs. Animals - 12 specific pathogen-free adult Beagles. Procedures - Dogs were topically inoculated in the right eye with CHV-1 (infection group; n = 8) or virus-free medium (control group; 4). Dogs were inoculated with or without corneal microtrephination and subconjunctivally administered corticosteroids. Conjunctiva, buffy coat, and serum samples for real-time PCR assay, virus isolation, and serum neutralization (SN) antibody titers were collected until postinfection day (PID) 224, and general physical and ophthalmologic examinations were performed. Results - Dogs in the infection group developed bilateral, mild to moderate conjunctivitis that reached maximal intensity on PIDs 7 to 10. Ocular viral shedding was detected in all dogs in the infection group between PIDs 3 and 10. Infected dogs developed CHV-1 SN antibody titers, beginning at PID 7 and peaking on PID 21. All buffy coat PCR assay results were negative. Corneal microtrephination and subconjunctival corticosteroid administration did not significantly affect clinical disease or viral shedding. Following recovery from primary infection, dogs remained clinically normal, did not shed virus, and had slowly decreasing SN antibody titers. Dogs in the control group did not develop conjunctivitis, shed virus, or develop CHV-1 SN antibody titers. Conclusions and Clinical Relevance - Primary ocular infection of adult dogs with CHV-1 was associated with self-limiting conjunctivitis and ocular viral shedding, which was evident in the absence of clinically detectable keratitis or systemic disease. Features of this infection resembled herpes simplex virus primary ocular infection in humans.