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.

Canine Reproductive, Respiratory, and Ocular Diseases due to Canine Herpesvirus

“…Experimental primary CHV genital mucositis in mature dogs, produced by intravaginal and intrapreputial CHV inoculation, resulted in genital viral shedding that was detected by virus isolation for up to 20 days. 46 Several dogs also developed nasal, pharyngeal, and conjunctival viral shedding during this period. Canine herpesvirus tracheobronchitis induced by intranasal viral inoculation was associated with viral shedding for up to 18 days.…”

“…Experimental primary ocular CHV infection in mature dogs produced by direct ocular surface inoculation resulted in conjunctival viral shedding that persisted for 10 days after inoculation. 46 Virus was detected in conjunctival samples by virus isolation and CHV PCR, and viral titers peaked 5 days postinoculation. CHV was inoculated into a single eye, but viral shedding was detected bilaterally in some dogs.…”

“…The blepharitis may represent self-trauma resulting from discomfort associated with conjunctival or corneal disease, or active viral infection of eyelid cutaneous epithelium as described for other dermal regions in dogs with CHV infection. 46 Conjunctivitis is the most frequently reported ocular lesion associated with both primary and recurrent CHV infection 44,47 and can be presented with conjunctival hyperemia, chemosis, and ocular discharge. Ulceration of the conjunctival epithelium may occur and appears as flat, irregular, pale or pink regions on the conjunctival surface surrounded by regions of hyperemia.…”

“…Under experimental conditions, acquisition of primary CHV infection by ocular surface inoculation consistently produces self-limiting conjunctivitis in immunocompetent mature dogs. 29,46 This route of infection likely occurs frequently under natural conditions and has direct clinical relevance. 47 Viral inoculation by other anatomic routes, such as the genital tract, is associated with inconsistent development of ocular disease.…”

Establishment and Characterization of an Air-Liquid Canine Corneal Organ Culture Model To Study Acute Herpes Keratitis

“…For CHV-1, no in vitro corneal epithelial cell culture systems have been developed to date, and only a few in vivo experimental models of primary ocular CHV-1 infections in dogs have been described (10,11). For FHV-1, a primary corneal cell culture model has been developed, but in general, FHV-1 ocular pathogenesis studies are almost exclusively done in live animals (4,12).…”