Lapis ISSN 2398-2969

Taenia pisiformis

Contributor(s): Vetstream Ltd, Will Easson, Molly Varga

Introduction

Classification

Taxonomy

  • Class: Cestoda.
  • Order: Cyclophyllidea.
  • Family: Taeniidae.
  • Genus:Taenia.
  • Species:pisiformis.

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Clinical Effects

Epidemiology

Habitat

  • Adult tapeworm in small intestine of rural and urban dogs that hunt and in other Canidae.
  • Segments and eggs in the environment are infective to rabbit/hare intermediate host.
  • Metacestode (cysticercus) on the liver and in the peritoneal cavity of rabbits and hares.

Lifecycle

  • See lifecycle diagram   Taenia pisiformis: lifecycle - diagram  :
    • Adult tapeworm   Taenia spp: adult  .
    • Gravid proglottid.
    • Egg.
    • Metacestode (cysticercus)   Taenia pisiformis: metacestode (cysticercus) 01    Taenia pisiformis: metacestode (cysticercus) 02 - surgical removal    Taenia pisiformis: metacestode (cysticercus) 03  .
    • Rabbit/hare intermediate host.

Transmission

Transmission to rabbit/hare
  • Segments migrate out of anus and fall to the ground.
  • Segments passed in feces migrate out onto grass or soil.
  • As segments migrate they leave a trail of thousands of eggs in a gelatinous film over the surface of grass, etc.
  • Eggs left by segments on feces can be eaten by flies and deposited over pasture.
  • Eggs eaten with herbage by rabbits or hares.

Transmission to dog

  • Metacestode (cysticercus) in abdomen of lagomorph eaten by hunting dog or dogs fed rabbit offal.

Pathological effects

  • Very little protective immunity develops in the dog population.
  • Protection (mainly antibody-mediated) can be induced by prior infection in rabbits.
In dog
  • The presence of 1 or many tapeworms usually has little effect on the health of a well-fed dog, burdens are usually only 1-10 tapeworms.
  • Irritation of a segment spontaneously migrating from the anus can cause 'scooting'.
  • Very large numbers of worms in young, poorly nourished dogs could reduce growth rates.
  • Very rarely, obstruction of the intestine from many hundreds of worms can occur.

In rabbit/ hare

  • Migrating cysts in rabbits' livers induce hemorrhage and inflammation followed by fibrosis. The white migratory tracts result in condemnation of livers in rabbits produced for human consumption.

Control

Control via animal

  • Anthelmintic treatment of dog.
  • Dogs that are free to hunt can be treated regularly, ie every 1-2 months.
  • Uncooked rabbit offal should not be fed to dogs.
  • Control not possible in rabbits.

Control via chemotherapies

Dogs

  • Either praziquantel   Praziquantel  (5-10 mg/kg PO SC or IM repeat after 10 days).
  • Fenbendazole   Fenbendazole  (20 mg/kg PO SID for 5 days).
  • Mebendazole   Mebendazole   compounded into the food at 1 g/kg feed (approximately 50 mg/kg dose) has been reported to kill both the immature and mature forms ofC. pisiformis.

Control via environment

  • Avoiding allowing potentially infected dogs to defecate on pasture that will be grazed by pet or production rabbits.

Diagnosis

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Further Reading

Publications

Refereed papers

  • Recent references fromPubMed.
  • Owiny J R (2001)Cysticercosis in laboratory rabbits.Contemporary Topics in Laboratory Animal Science40(2), 45-48PubMed.
  • Allan J C (1999)Helminth parasites of the wild rabbitOryctolagus caniculusnear Malham Tarn, Yorkshire, UK.J Helminthol73(4), 289-294PubMed.
  • Edwards G T & Herbert I V (1980)Some quantitative characters used in the identification of Taenia hydatigena,Taenia ovis,Taenia pisiformisandTaenia multicepsadult worms, andTaenia multicepsmetacestodes.J Helminthol55, 1-7PubMed.

Other sources of information

  • Hofing G L & Kraus L (1994)Arthropod and Helminth Parasites.In:Biology of the Laboratory Rabbit. 2nd edn. Eds: Manning P J, Ringler D H & Newcomer C E. Academic Press, London.

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