Lapis ISSN 2398-2969

Taenia serialis

Synonym(s): T. serialis, tapeworm cyst

Contributor(s): Vetstream Ltd, Dwight Bowman, Anna Meredith

Introduction

Classification

Taxonomy

  • Class: Cestoda.
  • Family: Taeniidae.
  • Genus:Taenia.
  • Species:serialis.

Overview

  • Tapeworm of the genusTaenia.
  • Dogs and foxes definitive hosts (and possibly Dingo): eggs (oncospheres) shed in feces of definitive host.
  • Rabbits and hares are intermediate hosts, infected after ingesting oncospheres.
  • The parasite migrates from intestine to predilection sites via circulation:
    • Coenurus, a fluid filled cyst or bladder, with many scolices develops in the intermidate host and usually forms a soft tissue swelling.
    • Coenurus comprises of the second stage larva, infective to definitive host.
    • Cysts develop in subcutis or intramuscular fascia: typically found in the head, neck and thoracic regions of pet rabbits.
    • Rabbis or hare ingested by definitive host to complete parasite lifecycle.
  • Cysts not life-threatening to the rabbit.
  • T. serialisis a differential diagnoss for soft tissue masses in rabbits and hars.
  • Surgery is treatment of choice in most cases.
  • Medical management options includes praziquantel administration.

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Clinical Effects

Epidemiology

Habitat

  • Adult tapeworm in small intestine of dogs that hunt and in other Canidae, including foxes.
  • Segments and eggs in environment.
  • Metacestode (coenurus) in subcutaneous or intramuscular tissues of rabbits and hares, rarely man, and rarely brain of cats.

Lifecycle

  • See lifecycle diagram    Taenia serialis: lifecycle - diagram  :
    • Adult tapeworm.
    • Gravid proglottid.
    • Egg.
    • Metacestode (coenurus).

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 (coenurus) eaten by hunting dogs, foxes or dogs fed rabbit meat.

Pathological effects

Rabbit/hare

  • A coenurus developing in the subcutaneous or intramuscular tissues of a pet rabbit presents as a soft tissue space-occupying lesion and may necessitate surgical removal.

Dog/fox

  • The presence of tapeworms (1 or many) 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.

Control

Control via animal

  • Anthelmintic treatment of dog   Praziquantel  .
  • Dogs that are free to hunt should be treated regularly, ie every 1-2 months.

Control via chemotherapies

  • Anthelmintics have not been tested specifically for efficacy againstT. serialis.
  • Drugs with efficacy againstTaenia pisiformisorTaenia hydatigenashould be used.
  • Praziquantel   Praziquantel   is most commonly used for control in pet rabbits:
    • Typical dose rate is 5-10 mg/kg PO - repeat dosing may be required in 10-14 days.
    • May be effective as a suspension injected into coenurus.
  • Nitroscanate (not available in US).
  • Epsiprantel.
  • Fenbendazole   Fenbendazole  .
  • Mebendazole    Mebendazole   (not available in US).
  • Dichlorophene not recommended.

Control via environment

  • Wash all vegetable matter offered to pet rabbits.
  • Avoid exposure of pet rabbits to areas frequented by dogs and foxes.

Diagnosis

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Further Reading

Publications

Refereed papers

  • Recent references fromPubMed.
  • O'Reilly A, McCowan C, Hardman C & Stanley R (2002)Taenia serialis causing exophthalmos in a pet rabbit.Vet Ophthamol5(3), 227-230PubMed.
  • Fountain K (2000)Coenurus seralis in a pet rabbit.Vet Rec147(12), 340PubMed.
  • Bennett H (2000)Coenurus cyst in a pet rabbit.Vet Rec147(15), 428PubMed.
  • Gasser R B, Zhu X & McManus D P (1999)NADH dehydrogenase subunit 1 and cytochormecoxidase subunit 1 sequences compared for members of the genusTaenia(Cestode).Int J Parasitol29, 1956-1970PubMed.

Other sources of information

  • Bowman D D (2003) Ed Georgis' Parasitology for Veterinarians.8th edn. W B Saunders. ISBN: 0721692834.

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