Overview
CHV causes a systemic infection in immunologically naïve animals; systemic disease in pups <2–3 weeks of age is usually fatal; systemic infection in naïve pregnant dams causes fetal death, mummification, and abortion. Pups born to immune dams develop life-long infection. After primary infection, CHV becomes latent in neurons of sensory ganglia, but can recrudesce when animals are stressed or are receiving immunosuppressive treatments leading to excretion in nasal secretions; recrudescence associated with mild respiratory illness or mild to severe ocular disease. Prevalence of latent infection is high; CHV ocular disease in adult animals is common, but underdiagnosed.
- Mature non-pregnant animals usually have inapparent, localized infections in the nasopharynx or external genitalia.
- Localized genital infections reported in both sexes.
Signalment
- All members of the canine family are susceptible.
- Death usually occurs between 9 and 14 days after birth; range is from 1 day (prenatal infection) to about 1 month (neonatal infection).
- Most commonly reported in purebred dogs, although there is no breed predilection. Ocular signs associated with CHV are common, but underdiagnosed.
Signs
- Dyspnea.
- Serous to mucopurulent nasal discharge.
- Anorexia.
- Grayish yellow or green, soft, odorless stool.
- Persistent, agonizing crying.
- Encephalitic signs.
- Severe gasping before death.
- Petechial hemorrhages on the mucous membranes occasionally seen.
- Incubation period in neonatal pups is 4–6 days.
- Onset sudden; death occurs 12–36 hours later.
- Some pups are found dead without premonitory signs.
- Occasionally, pups with mild signs survive but often later develop ataxia, persistent vestibular signs, or blindness.
- Mature females may have lymphofollicular or hemorrhagic lesions in the vagina.
- Infertility-evidence of increased seroprevalence in kennels with reproductive problems.
- Conjunctivitis-CHV is a common cause of acquired idiopathic conjunctivitis.
- CHV ulcerative keratitis-common sequelae of recrudescent infections.
Causes & Risk Factors
- CHV-typical herpesvirus; only one serotype described; latent infection is endemic in domestic dogs; young, naïve females and their newborn pups at greatest risk.
- Closed breeding kennels-CHV endemic; infection is less common and most adults are immune; newly introduced breeding bitches at high risk.
- Abortion storms with massive pup losses can occur when pregnant bitches maintained in private homes are assembled for whelping.
- Immunosuppressive drugs may provoke reactivation of latent CHV with associated transient ocular disease.
