# Prevalence and Clinical Impacts of Canine Herpesvirus‐1 (CHV‐1) in Dogs: A Review of Reproductive Effects and Ocular Lesions

## TL;DR

This paper reviews the global impact of Canine Herpesvirus-1 on dogs, focusing on its effects on reproduction and eye health, and suggests ways to manage and prevent its spread.

## Contribution

The paper provides a comprehensive review of CHV-1's clinical effects and management strategies, emphasizing its global prevalence and transmission.

## Key findings

- CHV-1 causes ocular lesions ranging from mild inflammation to severe corneal conditions in adult dogs.
- The virus can lead to reproductive issues such as fetal expulsion and preterm birth.
- Prophylactic antimicrobial therapy is recommended for managing ocular disease, but environmental temperature adjustments do not affect disease progression.

## Abstract

Canine herpesvirus‐1 (CHV‐1), as a member of the Varicellovirus, subfamily Alphaherpesvirinae and family Herpesviridae, is mainly transmitted at birth but can also spread venereally and transplacentally. In addition, CHV‐1 establishes a latent carrier state in the body and can reactivate due to stress or immunosuppression. CHV‐1 distribution varies worldwide but is believed to have a global distribution. CHV‐1 infection in adult canines can manifest as a spectrum of ocular from eyelid inflammation (blepharitis) and conjunctival inflammation (conjunctivitis) to more severe corneal conditions, including ulcerative and non‐ulcerative keratitis. Moreover, CHV‐1 in adult canines can lead to a range of reproductive effects, from submucosal vascular congestion and bleeding to foetal expulsion and preterm birth of live offspring. Subclinical or mildly symptomatic upper respiratory tract disease can manifest in juvenile and adult canines. Prophylactic topical antimicrobial therapy is recommended to prevent disease progression in dogs with CHV‐1 ocular disease. However, the environmental temperature increase for affected puppies fails to modify the disease progression. Environmental variables, including breeding facility size and animal population density, facilitate herpesvirus transmission and subsequent immune responses. There are various diagnostic techniques, but the most prevalent method is polymerase chain reaction (PCR) for viral DNA detection. Due to the global distribution of the virus and its effects, such as ocular and reproductive effects and subsequent financial losses, it is recommended that infected dogs be identified and treated promptly, as well as prevent its transmission.

Taxonomy: Herpesviridae, Alphaherpesvirinae and Varicellovirus.

Diagnosis: PCR for genetic detection.

Transmission: Birth, venereal and transplacental.

Pathogenesis: Ocular lesions; blepharitis, conjunctivitis and ulcerative and non‐ulcerative keratitis.

Reproductive effects: submucosal vascular congestion and bleeding to foetal expulsion and preterm birth of live offspring.

Subclinical or mildly symptomatic URTD.

Latency and reactivation (stress/immunosuppression).

Management: Prophylactic topical antimicrobial therapy in dogs with CHV‐1 ocular disease.

Enhance breeding facility size and animal population density.

Identify and treat infected dogs promptly in order to prevent its transmission.

Antimicrobial therapy and antiviral agents.