Canis ISSN: 2398-2942

Canine parvovirus

Synonym(s): Parvo

Contributor(s): Susan Dawson, Melissa Kennedy




  • Family: Parvoviridae.
  • Genus: Parvovirus.
  • CPV 1: also known as minute virus of canines.
  • CPV 2: several variants identified including CPV 2a, 2b and 2c.


  • Latin: parvus- small.

Active Forms

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Clinical Effects



  • Canine parvovirus survives in the gastrointestinal tract of dogs.
  • Cats may be a potential reservoir, as canine and feline parvoviruses are closely related.
  • CPV 2a and CPV 2b can infect cats.
  • May survive for years in the environment.


  • Replicates in actively dividing cells of the natural host.
  • Single-stranded DNA virus.
  • Virions are assembled in the cell nucleus, associated with the formation of intranuclear inclusion bodies.


  • Feco-oral route.
  • Environmental contamination more important than contact with infected dog.
  • Via food and water contaminated with feces containing virus. The virus can survive in the environment for long periods.

Pathological effects

  • Virus targets lymphoid tissue, resulting in (in the early stages at least) lymphocytolysis and leukopenia.
  • Viremia followed by infection of bone marrow → leukopenia.


  • Mild diarrhea.


  • Initial sites of replication are lymph nodes and spleen.
  • Viremia occurs 2-5 days after infection.
  • The intestinal mucosa is involved after 6 days, targets intestinal crypt cells → complete denudation of mucosa in severe infections → fecal excretion follows.
  • Damage to the small intestine allows secondary bacterial infection, vomiting, diarrhea, and endotoxemia (diarrhea often hemorrhagic).
  • As parvovirus can cross the placenta pregnant bitches should not be immunized with modified live parvovirus vaccine; could cause abortion or fetal infection.
  • Myocarditis may occur in puppies when infected between 3 and 8 weeks old. Necrosis and infiltration by mononuclear cells occurs in the ventricular myocardium.

Other Host Effects

  • Virus is excreted in the feces for up to 8 weeks after recovery. This maintains the virus in the environment.


Control via chemotherapies

  • Interferon Interferon.
  • Symptomatic:
    • Replace fluid and electrolyte losses.
    • May use antibiotics to prevent 2° sepsis.
    • Anti-emetics to control vomiting.


  • Most adult animals are immune due to vaccination or exposure.
  • Antibody levels correlate directly with degree of protection.
  • Modified live vaccine usually stimulates a good antibody response.
  • Live modified vaccine available Therapeutics: immunological preparation Vaccination protocols.
  • Interference from maternal immunity is a significant problem. Initial puppy vaccinations are recommended to finish at an age when maternally derived antibody has declined to low levels such that the animal can respond to vaccination: this may be up to 16 weeks especially where prevalence of infection in the population is high.

Other countermeasures

  • Prompt cleaning with effective disinfectants, eg bleach.
  • Remove organic material, eg feces prior to disinfection.


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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Decaro N, Martella V, Elia G et al (2007) Tissue distribution of the antigenic variants of canine parvovirus type 2 in dogs. Vet Microbiol 121 (1-2), 39-44 PubMed.
  • Martella V, Decaro N & Buonavoglia (2006) Evolution of CPV-2 and impliance for antigenic/genetic characterisation. Virus Genes 33 (1), 11-13 PubMed.
  • Martella C, Cavalli A, Pratelli A et al (2004) A canine parvovirus mutant is spreading in Italy. J Clin Microbiol 42 (3), 1333-1336 PubMed.
  • Cohn L A, Rewerts J M, McCaw D et al (1999) Plasma granulocyte colony-stimulating factor concentrations in neutropenic, parvoviral enteritis-infected puppies. JVIM 13 (6), 581-586 PubMed.
  • Horiuchi M, Yamaguchi Y, Gojobori T et al (1998) Differences in the evolutionary pattern of feline panleukopenia virus and canine parvovirus. Virology 249 (2), 440-452 PubMed.
  • Houston D M, Ribble C S & Head L L (1996) Risk factors associated with parvovirus enteritis in dogs: 283 cases. JAVMA 208 (4), 542-546 PubMed.
  • Greenwood N M, Chalmers W S, Baxendale W et al (1995) Comparison of isolates of canine parvovirus by restriction enzyme analysis, and vaccine efficacy against field strains. Vet Rec 136 (3), 63-67 PubMed.