Felis ISSN 2398-2950

Trematode infections

Contributor(s): Ian Wright, Maggie Fisher

Introduction

  • Cause: trematode infections include Clonorchis sinensis, Metagonimus spp, Nanophyetus salmincolaOpisthorchis felineus and Paragonimus kellicotti.
  • May also be infected by Fasciola hepatica but this is rare in cats and dogs.
  • SignsParagonimus kellicotti infection can lead to coughing, dyspnea, pneumothorax, bronchiectasis, and hemoptysis. Other fluke infections may lead to enteritis and hepatopathies.
  • Diagnosis: clinical signs, trematode eggs in feces or sputum.
  • Treatment: Praziquantel, supportive.
  • Prognosis: good with appropriate treatment.

Pathogenesis

Etiology

  • Adult trematodes present in the lungs, liver or alimentary system.

Predisposing factors

General

  • Access to raw or undercooked fish or shellfish.

Pathophysiology

  • Source of infection for cats is raw/undercooked fish and shellfish intermediate hosts.
  • Metacercariae in fish or shellfish.
  • Young flukes rapidly penetrate the intestinal tract and enter the peritoneal cavity or in the case of Metagonimus spp develop to adulthood in the small intestine.
  • Paragonimus kellicotti migrates to the lungs where cysts form containing paired flukes. Eggs are passed in the sputum or coughed, swallowed and passed in the feces.
  • Small number of worms well-tolerated.
  • Presence of flukes may be associated with villous atrophy, malabsorption, increased thickness of intestinal muscle layers, hepatitis, bile duct obstruction.
  • The larger the worm burden the higher the risk of pathology and subsequent clinical signs.

Timecourse

  • Pre patent period typically 5-7 weeks.
  • Clinical signs may be seen earlier due to immature stages and fluke migration.

Diagnosis

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Treatment

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Prevention

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Enes J E, Wages A J, Malone J B et al (2010) Prevalence of Opisthorchis viverriniinfection in the canine and feline hosts in 3 villages, Khon Kaen Province, northeastern Thailand. Southeast Asian Journal of Tropical Medicine and Public Health 41 (1), 36-42 PubMed
  • Lun Z R, Gasser R B, Lai D H et al (2005) Clonorchiasis: a key foodborne zoonosis in China. Lancet Infectious Disease (1), 31-41 PubMed
  • Bowman D D, Frongillo M K, Johnson R C et al (1991) Evaluation of praziquantel for treatment of experimentally induced paragonimiasis in dogs and cats. Am J Vet Res 52 (1), 68-71 PubMed.


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