Canine Herpesvirus‐1 Ocular Infection in Japan: A Case Report

To describe the clinical manifestations and therapeutic outcomes of ocular infection caused by canine herpesvirus 1 (CHV-1), including both typical and atypical features. A client-owned 5-year-old castrated male French Bulldog presented with dendritic corneal ulcers, quantitative tear deficiency, and corneal hypoesthesia in the left eye. A diagnosis of CHV-1 ocular infection was made based on the characteristic presentation of dendritic corneal ulcers and confirmed by polymerase chain reaction (PCR) analysis of a conjunctival swab. Antiviral therapy with 0.1% idoxuridine ophthalmic solution was initiated on Day 8, and follow-up ophthalmic examinations were performed on Days 14, 37, and 58. To monitor viral shedding, conjunctival swabs were collected before and after the initiation of antiviral treatment and analyzed using the quantitative PCR method. Resolution of the corneal ulcers, along with improvement in corneal sensitivity and tear production, was observed. Quantitative PCR revealed a reduction in viral shedding following treatment. No recurrence of ocular lesions was noted by the time of the final follow-up examination. To the authors' knowledge, this is the first documented case of CHV-1 ocular infection in an adult dog in Japan. These findings suggest that CHV-1 may cause not only characteristic corneal ulcers but also associated corneal hypoesthesia and quantitative tear deficiency.