Felis ISSN 2398-2950

Hookworm disease

Contributor(s): Maggie Fisher, Ian Wright

Introduction

  • Cause: classical hookworm disease caused by Ancylostoma spp, primarily A. tubaeforme in UK Cats.
  • Rare in the UK and when present likely to be caused by Ancylostoma spp. While the "northern hookworm"Uncinaria stenocephala can infect cats, it rarely reaches the numbers required to cause clinical disease. Common in the US and more southern parts of mainland Europe where disease also caused by A. braziliense.
  • A. braziliense is a recognized zoonosis.
  • Signs: hookworm disease severity and clinical signs depend on the level of infection with heavy infections leading to weight loss and a progressive, potentially fatal anemia. Lighter infections produce a stabilizing regenerative anemia with varying levels of lethargy, inappetence, diarrhea, possibly with melena, less commonly dermatitis.
  • Diagnosis: signs, worms seen. Fecal flotation for ova.
  • Treatment: anthelmintics and environmental control.
  • Prognosis: good with appropriate treatment.

Pathogenesis

Etiology

  • Hookworm disease is caused by infection with immature or adult hookworm populations.

Predisposing factors

General

  • Access to infected runs, catteries, poorly cleaned litter trays.
  • Inadequate worm control.
  • Warm, wet weather (so disease maybe seasonal in incidence, eg may be seen in autumn after a warm wet summer).

Specific

  • Disease may be seen before the worms reach adulthood, ie in the pre-patent period.
  • Chronic infection associated with prolonged exposure to a significant hookworm population.

Pathophysiology

  • Worms ingest blood and tissue fluid and damage small intestinal mucosa so that blood/fluid loss continues even when worm itself has moved to a new feeding site.
  • In acute Ancylostoma spp infection, severe enough anemia can be caused that the animal has no time to compensate for the degree of blood loss.
  • In heavy chronic Ancylostoma spp infection infection may be seen if the rate of blood loss exceeds the animal's capacity for compensation.
  • Acute symptoms may also be seen in older cats receiving a sudden large challenge for the first time.
  • As worms move to fresh feeding locations they may leave bleeding ulcers.
  • A. tubaeforme is a significant blood feeder. 
  • A.braziliense is less pathogenic removing only in the region of 0.008 ml blood per worm per day.
  • U.stenocephala worms damage the mucosa, resulting in protein losing enteropathy. Blood loss less severe.
  • Eggs passed in feces embryonate and hatch into infective larvae within a week in ideal conditions.
  • Cats then reinfected when they ingest infective third stage larvae.
  • Infection may occur through the percutaneous route.
  • Transplacental transmission does not occur or not to any significant extent. It has been speculated that transmammary infection may occur in Ancylostoma spp infections but this has not been demonstrated definitively.

Timecourse

  • Pre-patent period approximately 14-28 days.
  • Disease may be seen before patent infection develops.

Epidemiology

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.
  • Prullage J B, Knaus M, Bowman D D et al (2014) Efficacy of a novel topical combination of fipronil, (S)-methoprene, eprinomectin and praziquantel against induced infections of Ancylostoma spp. nematodes of cats. Vet Parasitol 202 (1-2), 30-33 PubMed.
  • Liotta J L, Koompapong K N, Yaros J P et al (2012) Prevalence of Ancylostoma braziliense in cats in three northern counties of Florida, United States. J Parasitol 98 (5), 1032-1033 PubMed
  • Lucio-Forster A, Liotta J L, Yaros J P et al (2012) Morphological differentiation of eggs of Ancylostoma caninumAncylostoma tubaeforme, and Ancylostoma braziliense from dogs and cats in the United States. J Parasitol 98 (5), 1041-1044 PubMed.
  • Prociv P & Croese J (1996) Human enteric infection with A. caninum - hookworms reappraised in the light of a "new zoonosis". Acta Tropica 62 (1), 23-44 PubMed.
  • Kalkofen U P (1987) Hookworms of dogs and cats. Vet Clin N Am Small Anim Pract 17 (6), 1341-1354 PubMed.

Other sources of information

  • Georgis' Parasitology for Veterinarians. (1995) 6th edn. Ed Bowman D D; W B Saunders ISBN 0-7216-5589-0.


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