Equis ISSN 2398-2977

Anoplocephala spp

Contributor(s): Susan Dawson, Sheelagh Lloyd

Introduction

Classification

Taxonomy

  • Class:Cestoda.
  • Family:Anoplocephalidae.
  • Genus:Anoplocephala,Anoplocephaloides(Paranoplocephala).
  • Species:perfoliata,magna,mamillana.

Etymology

  • Gk:anoplos- unarmed;kephalikos- head.

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Clinical Effects

Epidemiology

Habitat

  • Oribatid mites (intermediate hosts) on pasture harbor cysticercoids.
  • Maximum numbers of infected mites in late summer/autumn.

Lifecycle

  • Adult tapeworms   Tapeworm infection  in equine intestine   →   mature segments passed in feces   →   disintegrate to release eggs   →   eggs ingested by forage mites   →   develop into cysticercoids in 2-4 months in mites   →   infected mites ingested by horses   →   adult tapeworms develop over 6-10 weeks.
  • Numbers of mature worms increase in autumn with egg-laying adults most common in winter through spring.
  • A. perfoliatalives about 6 months.

Transmission

  • Feco-oral via intermediate host (forage mite).

Pathological effects

  • Heavy infections may cause clinical signs   Tapeworm infection  .
  • A. perfoliataattaches around ileo-cecal junction   Anoplocephala perfoliata: ileocecal valve infestation 01 - pathology   and cecal wall   Anoplocephala perfoliata: ileocecal valve infestation 02 - pathology   and occasionally ileum   Anoplocephala perfoliata: ileum infestation - pathology   and ventral colon    →   ulceration   →    may lead to intussusception and spasmodic colic and granulation and worms may   →    impaction.
  • A. magnausually found in jejunum may cause hemorrhagic enteritis.
  • Either species may cause intestinal obstruction or perforation if present in sufficient numbers.

Other Host Effects

  • Most infections subclinical.

Control

Control via animal

  • Treat with anthelminthic before horses enter new grazing.

Control via chemotherapies

  • Periodic specific drug treatment helps to reduce the heavy burdens associated occasionally with disease.
  • A. perfoliata- praziquantel (1 mg/kg) and pyrantel   Pyrantel   (13.2 mg/kg) are very effective; pyrantel (single dose 6.6 mg/kg) has some 70% efficacy; pyrantel (2.64 mg/kg daily for 14 days) is very effective. Benzimidazoles have reported variable but slight effect. These are assumed to have efficacy againstA. magna.
  • A. mamillana- praziquantel must be used; pyrantel reportedly has no effect.
  • Macrocyclic lactones - moxidectin and ivermectin are ineffective against tapeworms.

Control via environment

  • Impossible to control forage mites. Numbers reduced for a year or more after ploughing and cropping. 
  • Reduce fecal contamination of pasture by picking up feces.

Diagnosis

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Meana A, Pato N F, Martin R, Mateos A et al (2005) Epidemiological studies on equine Cestodes in central Spain: infection pattern and population dynamics. Vet Parasitol 130, 233-240 PubMed.

Other sources of information

  • Urquhart G M, Armour J, Duncan J L, Dunn A M & Jennings F W (1987) Veterinary Parasitology Chelmsford: Longman Scientific. pp 126-128. ISBN: 0 582 40906 3.

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