Pathological changes occur in the kidneys, and consist of petechial or ecchymotic hemorrhages and focal necrosis, giving the kidneys a classical speckled or "paint brush hemorrhage" appearance. Multifocal areas of necrosis and hemorrhage occur in several organs, including the lung, liver, brain and intestine, and placental necrosis occurs in infected pregnant females. Meningoencephalitis is common, and lymph nodes and spleens are enlarged. Primary genital infections are characterized by lymphofollicular lesions and vaginal hyperemia, and severely affected bitches may have ecchymotic submucosal hemorrhages.

An inactivated, subunit vaccine (Eurican Herpes 205, Merial Animal Health) has been available in Europe since 2003. It is not available in the Unites States. It consists of purified CHV glycoproteins in a mineral oil solvent. The vaccine is specifically indicated for bitches during pregnancy and two doses are given, first during estrus or early pregnancy and the second 1–2 weeks before the expected date of whelping. Although it has few undesirable effects, transient edema may occur at the injection site for up to one week. Presently, the value CHV vaccines in reducing neonatal puppy mortality is unknown.

Antiviral drugs have been generally unsuccessful, although vidarabine given before the onset of symptoms may be helpful. While antiviral treatment may spare life, residual damage to the central nervous system and heart may occur. Success in preventing subsequent CHV illness in previously affected dams has been achieved in a few cases by: harvesting plasma at the time of the initial clinical infection from infected dams or kennel mates determined to have anti-CHV antibodies, taking the puppies by cesarean section, and giving them two doses of the plasma perinatally (orally) and then 5–-7 days later (IP). Such treatment is effective only if virus has not generalized. Once illness develops in pups, anti-CHV plasma therapy is ineffective.

This small canine parvovirus (CAV-1) was first isolated in 1967 from the feces of healthy military dogs in Germany. Most closely related to bovine parvovirus, CAV-1 was considered non-pathogenic for 20 years until research revealed its pathogenicity for the fetus and newborn pups. While about 40 field cases have been documented throughout the world, serologic evidence of CPV-1 is widespread (50-70%) in the dog populations of USA, Japan, and Switzerland.

Infected pups die suddenly between 1–3 weeks of age with respiratory distress and/or severe diarrhea. Surviving littermates have vague signs, e.g., anorexia, failure to nurse or eat, and mild respiratory illness or diarrhea. Transplacental infections with fetal deaths ("fading pups," viral myocarditis), and abortion have been demonstrated experimentally. Viral pneumonia is common, with abundant inclusion bodies in bronchial epithelial cells. Additional changes in nursing pups include thymic edema and atrophy, enlarged and soft lymph nodes, and soft, pasty stools. Diagnosis is difficult because of the lack of commercially available reagents. In laboratories where specific antibodies and WR3873-D cells are available, the virus can be readily identified by immunofluorescence or immunocytochemistry.

References: Carmichael, Recent Adv Can Infect Dis, IVVS, 2004; Mochizuki et al, J Clin Microbiol 40:3993-3998, 2002; Schwartz et al, Virology 302:219-223, 2002.