Felis ISSN 2398-2950

Canine parvovirus

Synonym(s): Parvo

Contributor(s): Susan Dawson, Melissa Kennedy

Introduction

Classification

Taxonomy

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

Etymology

  • Latin: parvus- small.

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Clinical Effects

Epidemiology

Habitat

  • 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.

Lifecycle

  • 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.

Transmission

  • 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 (during the early stages at least), lymphocytolysis and leucopenia.
  • Viremia followed by infection of bone marrow   →   leucopenia.

CPV 1

  • Mild diarrhea in dogs.

CPV 2

  • Severe signs in dogs:
    • 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

Control via chemotherapies

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

Vaccination

  • Most adult dogs 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 for dogs Therapeutics: immunological preparation.
  • 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.

Diagnosis

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Further Reading

Publications

Refereed papers

  • Recent references from VetMed Resource and PubMed.
  • Decaro N, Martella V, Elia G, Desario C, Campolo M, Lorusso E, Colainni M L, Lorusso A & Buonavoglia C (2007) Tissue distribution of the antigenic variants of canine parvovirus type 2 in dogs. Vet Microbiol 121, 39-44 PubMed.
  • Martella V, Decaro N & Buonavoglia (2006) Evolution of CPV-2 and impliance for antigenic/genetic characterisation. Virus Genes 33, 11-13 PubMed.
  • Martella C, Cavalli A, Pratelli A, Bozzo G, Camero M, Buonavogli D, Narcisi D, Tempesta M & Buonavoglia C (2004) A canine parvovirus mutant is spreading in Italy. J Clin Microbiol 42, 1333-1336 PubMed.
  • Gamoh K, Shimazaki Y, Senda M, Makie H, Itoh O & Inoue Y (2003) Antigenic type distribution of parvovirus isolated from domestic cats in JapanVet Rec 153(24), 751-752 PubMed.
  • Cohn L A et al(1999) Plasma granulocyte colony-stimulating factor concentrations in neutropenic, parvoviral enteritis-infected puppies. J Vet Int Med 13(6), 581.
  • 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.
  • 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.
  • Greenwood N M, Chalmers W S, Baxendale W & Thompson H (1995) Comparison of isolates of canine parvovirus by restriction enzyme analysis, and vaccine efficacy against field strains. Vet Rec 136(3), 63-67.

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