Feline panleukopenia (parvo) in Cats (Felis) | Vetlexicon
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Feline panleukopenia (parvo)

ISSN 2398-2950

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Synonym(s): Feline panleucopenia virus, feline infectious enteritis (FIE, feline parvo (FPV

Introduction

Classification

Taxonomy

  • Family: Parvoviridae.

Etymology

  • Parvo - latin for small.
  • Pan = all, leuko = white, penia = lack of. Hence pan-leuko-penia = decrease of all white blood cells.

Distribution

  • Worldwide.

Significance

In cat

  • Present as rapid onset dehydration, vomiting, collapse.
  • Virus attacks lymphocytes in lymphoid tissue and leukocytic stem cells in bone marrow causing decreased white blood cell counts.
  • Most susceptible kittens probably subclinically infected.
  • Associated with deaths in kittens from days to months of age in rescue shelters and at cat breeders (Addie et al, 1997).
  • Recently, canine parvovirus has been isolated from cats showing FPV-like disease (Mochizuki et al, 1996, Truyen et al, 1996).
  • Abortion if non-immune queen infected in first half of pregnancy.

In human

  • Not zoonotic.

Active Forms

Active Form 1

Morphology

  • Small (20 nm in diameter) unenveloped, single-stranded DNA virus, icosahedral capsid.

Taxonomy

  • Parvoviridae.

Tolerances

Temperature
  • Very resistant to heat and high or low pH, surviving a year or more in the environment.
Other
  • Susceptible only to a few disinfectants: glutaraldehyde, hypochlorite or formaldehyde.

Development

Reproduction
Replication
  • FPV replicates in the dividing cells of cats: the epithelium of the crypts of the small intestine, the bone marrow, the cerebellum of the fetus or neonate up to 14 days old.
  • Parvovirus DNA replicates in the nucleus of the cell.
Longevity
  • FPV lasts at least a year in the environment.

Resting Forms

Clinical Effects

Epidemiology

Lifecycle

  • Contact  →  replicates in lymphoid tissue  →  lymphatics  →  viremia  →  rapidly dividing cells.
  • Grow in nucleus of dividing cells, rapid immune response by cat eliminates virus which then survives in the environment for up to a year until next susceptible animal ingests it.

Transmission

  • FPV is shed in the feces of infected cats for a short period of time, usually up to 48 hours, but has been documented for up to 6 weeks. Most infections occur by indirect transmission, from a contaminated environment, by ingestion of virus.
  • Transplacental.

Pathological effects

  • FPV is highly immunogenic. Protection is humoral, hemagglutination inhibition (HAI) titers of up to 256 follow vaccination and antibody titers of greater than 1024 usually indicate that natural exposure to FPV has occurred.
  • Severity of disease varies from subclinical to death.
  • Lesions usually present in jejunum and ileum, petechial hemorrhages on serosal and mucosal surfaces.
  • Destruction of crypt cells lead to loss of villous epithelium and massive fluid loss into gut   →   death due to dehydration.
    • The cat may vomit Vomiting.
    • If the cat survives long enough, profuse, watery diarrhea may occur. Diarrhea may be hemorrhagic.
    • Temperature normal to subnormal.
  • Decrease of all white blood cells.
  • Sudden death, especially of kittens, may be confused with poisoning.
  • Cerebellar hypoplasia - ataxia when kittens start to walk at 10-14 days old.

Control

Control via chemotherapies

Control via environment

  • Disinfection using hypochlorite or glutaraldehyde disinfectants may help to reduce virus dose but will not eliminate infection.
  • In an environment contaminated with FPV, no susceptible cats or kittens should be introduced until at least a year after the outbreak. Pregnant queens should be removed to a clean area, ie other premises, until the kittens are old enough to be fully vaccinated.

Vaccination

  • Modified live and inactivated vaccines Therapeutics: immunological preparation are available.
  • In the absence of maternally derived antibody (MDA), kittens as young as 7-12 days can respond to vaccination.
  • Modified live vaccines should not be given to pregnant queens (danger of cerebellar hypoplasia in kittens) or kittens up to 4 weeks old.
  • MDA levels as low as titer 10 can interfere with vaccination up to 19-20 weeks of age, though most kittens can be successfully vaccinated at 12 weeks old. If the queen has a high antibody titer, or there is a history of FPV infection in the premises, check the post-vaccinal antibody titer, which should be greater than 64 for protection. The half-life of MDA to FPV is 9.5 days.
  • A plant-derived parvovirus vaccine protected mink (Dalsgaard et al, 1997) but no such product is yet commercially available for cats.

Diagnosis

Useful samples

  • FPV may be isolated in cell culture by specialized laboratories.
  • Send feces (from living cat) or intestinal contents (from dead cat or kitten) to a specialized laboratory, eg Feline Virus Unit, Glasgow University, for detection of FPV by electron microscopy.
  • Include 1 ml blood, serum or plasma for detection of antibodies because parvovirus can pass very quickly out of the intestine and not be detectable by the time the cat is clinically ill.
  • Cats which have been naturally exposed have much higher antibody titers (>1024) than those which are vaccinated. If the animal is dead, send 1-2 cm pieces of the jejunum, ileum, duodenum, colon and mesenteric lymph node in 10% formol saline for histopathological confirmation of infection. Pieces of small intestine should be taken as soon as possible after death, before autolysis occurs.
    Do not tie off the ends.
  • Do not freeze body before sampling for histopathology, but can still use the gut contents of a cat which has been frozen.
  • Where ataxia was the presenting sign, send the brain in 10% formalin.

Specimen storage

  • Blood should be separated and the plasma or serum frozen at -20°C if not to be sent immediately. Feces or intestinal contents can be stored in the fridge.
  • Corpses should not be frozen prior to sampling, as this disrupts the cells and makes histopathology nearly impossible.

Transport of samples

  • Since the virus in feces/intestinal contents and organs in formalin are so hardy, ordinary post is fine. Blood, plasma or serum should be sent by first class post.

Field diagnosis

  • Suspect FPV when cat or kitten presents with sudden death, is very weak and dehydrated, with vomiting. Check vaccination record - either unvaccinated or possibly vaccinated too early (see under Vaccination).
  • Other conditions with similar clinical picture - poisoning, Aujesky's disease (if pigs nearby).
  • In kittens: feline herpes virus.
  • Commercial kits for canine parvovirus may miss up to 50% of feline parvovirus cases (Addie et al, 1997). However, Parvo Clinic, a rapid immunomigration assay from European Veterinary Laboratories is very sensitive to both CPV and FPV.

Laboratory diagnosis

  • Parvo ELISA Enzyme linked immunosorbent assay (ELISA) available (Canine and feline parvovirus cross-react; cat may be infected with CPV).
  • FPV detected by rapid immunomigration test (Feline Virus Unit, Glasgow University) or virus isolation (specialized laboratories, eg Neil Greenwood, Intervet). Alternatively, the virus can be identified by electron microscopy.
  • HAI titers to distinguish between natural exposure (>1024) and vaccination titers (usually <256). Serology can also be done by immunofluorescence.
  • Histopathology of small intestine.
  • FPV is differentiated from CPV by its ability to agglutinate porcine erythrocytes at pH 6.4 rather than 7.2, by antigenic analysis in a hemagglutination inhibition (HAI) test and by restriction enzyme analysis (only very specialized laboratories).

Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Gamoh K, Shimazaki Y, Senda M et al (2003) Antigenic type distribution of parvovirus isolated from domestic cats in Japan. Vet Rec 153 (24), 751-752 PubMed.
  • Dawson S, Willoughby K, Gaskell R M et al (2001) A field trail to assess the effect of vaccination against feline herpesvirus, feline calicivirus and feline panleucopenia virus in 6-week old kittens. J Feline Med Surg (1), 17-22 PubMed.
  • Dawson S, Gaskell R & Jarrett O S (1999) Vaccination in cats - an update. In Practice 21 (2), 71-74 VetMedResource.
  • Addie D D, Toth S, Thompson H et al (1998) Detection of feline parvovirus in dying pedigree kittens. Vet Rec 142 (14), 353-356 PubMed.
  • Dalsgaard K, Uttenthal A, Jones T D et al (1997) Plant-derived vaccine protects target animals against a viral disease. Nat Biotechnol 15 (3), 248-252 PubMed.
  • Mochizuki M, Horiuchi M, Hiragi H et al (1996) Isolation of canine parvovirus from a cat manifesting clinical signs of feline panleukopenia. J Clin Microbiol 34 (9), 2101-2105 PubMed.
  • Truyen U, Evermann J F, Vieler E et al (1996) Evolution of canine parvovirus involved loss and gain of feline host range. Virology 215 (2), 186-189 PubMed.

Organization(s)

Supplier of Parvo Clinic tests
  • European Veterinary Laboratory- Zaagmolenlaan 4, 3447GS WOERDEN, The Netherlands. Fax: 00 31 3484 14626.
Virus detection, antibody measurements, histopathology
  • Feline Virus Unit- Department of Veterinary Pathology, University of Glasgow, Bearsden Road, Glasgow, G61 1QH, Scotland. Tel: + 44 141 330 5777; Fax: + 44 141 330 5748; E-mail: Feline@udcf.gla.ac.uk.