Canis ISSN: 2398-2942

Taenia hydatigena

Synonym(s): T. hydatigena

Contributor(s): Stephen Barr

Introduction

Classification

Taxonomy

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

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Clinical Effects

Epidemiology

Habitat

  • Adult tapeworm in small intestine of rural dogs that are fed or scavenge sheep offal and in other Canidae.
  • Segments and eggs in environment.
  • Metacestode (cysticercus), on liver and viscera of sheep Taenia hydatigena metacestode (cysticercus) from sheep peritoneal cavity 01 , and also goats, cattle, pigs, buffaloes, etc.

Lifecycle

  • See lifecycle diagram Lifecycle Taenia hydatigena - diagram :
    • Adult tapeworm.
    • Gravid proglottid.
    • Egg.
    • Metacestode (cysticercus).

Transmission

Transmission to sheep
  • Segments migrate out of anus and fall to the ground Taenia spp segment migrating spontaneously from the anus.
  • 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 Taenia spp egg film from migrating segment.
  • Eggs left by segments on feces can be eaten by flies and deposited over pasture.
  • Eggs eaten with herbage by sheep, goats or other animals.
Transmission to dog
  • Metacestode (cysticercus), in abdomen of sheep/goat eaten when the dog is scavenging or fed offal.

Pathological effects

Dog

  • Very little protective immunity develops.

Sheep

  • Protection is rapidly induced by prior infection with as few as 10 eggs.

Dog

  • The presence of tapeworms (1 or many), usually has little effect on the health of a well-fed dog. Burdens are usually only 1-13 tapeworms.
  • Irritation of a segment spontaneously migrating from the anus Taenia spp segment migrating spontaneously from the anus , can cause 'scooting'.
  • Very large numbers of worms in young, poorly-nourished dogs could reduce growth rates Tapeworm in a dogs intestine.
  • Very rarely, obstruction of the intestine from many hundreds of worms can occur.

Sheep, goat, etc

  • Migrating cysts in the liver → hemorrhage and inflammation → fibrosis. A large intake of eggs in young, naive lambs or goat kids can produce deaths from traumatic hepatitis. At lower levels, the white migratory tracts, white spots or white/green calcified cysts result in trimming or condemnation of livers in sheep and other animals.

Control

Control via animal

  • Anthelmintic treatment of dog.
  • Dogs should be well-fed, prevented from scavenging and should not be fed sheep offal.
  • Uncooked offal should not be fed to dogs.

Control via chemotherapies

Either Praziquantel Praziquantel.
Or Nitroscanate Nitroscanate.
Or Fenbendazole Fenbendazole.
Or Mebendazole Mebendazole.
Or Dichlorophenamide.

Other countermeasures

The hyperendemic stability of T. hydatigena can be destablized if treating with praziquantel every 6 weeks as part of a control program aimed at eradicating Echinococcus granulosus Echinococcus granulosus.

Diagnosis

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Further Reading

Publications

Refereed papers

  • Recent references from VetMed Resource and PubMed.
  • Cabrera P A, Parietti S, Haran G, Benavidez U, Lloyd S, Perera G, Valledor S, Gemmell M A & Botto T (1996) Rates of reinfection with Echinococcus granulosus, Taenia hydatigena, Taenia ovis and other cestodes in a rural dog population in Uruguay. Intern J Parasitol 26, 79-83.
  • Dempster R & Harrison G B L (1996) Parasite vaccine development: large scale recovery of immunogenic Taenia ovis fusion protein GST-45W(B/X) from Escherichia coli inclusion bodies. Parasitology Research 82, 291-296.
  • Lawson, J R (1994) Hydatid disease and sheep measles - the history of their control and economics of a recent change in control policy. New Zealand Journal of Zoology 21, 83-89.
  • Lloyd S, Martin S C, Walters T M H & Soulsby E J L (1991) Use of sentinel lambs for early monitoring of the South Powys Hydatidosis Control Scheme: prevalence of Echinococcus granulosus and some other helminths. Vet Rec 129, 73-76.
  • Anderson F L, Jensen L A, McCurdy H D et al (1986) Three-year surveillance for cestode infections in sheep dogs in central Utah, USAGreat Basin Naturalist 46, 208-216.

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