Bovis ISSN 2398-2993

Bunostomum spp

Synonym(s): Hookworm

Contributor(s): Ash Phipps , Andrew Forbes

Introduction

Classification

Taxonomy

  • Phylum: Nematode.
  • Class: Chromadorea.
  • Order: Rhabditida.
  • Suborder: Strongylida.
  • Family: Ancylostomatidae.
  • Genus: Bunastomum.

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Clinical Effects

Epidemiology

Habitat

  • Adults inhabit the gastrointestinal tract .
  • Eggs are passed in the feces.
  • L1 and L2 inhabit the feces.
  • L3 inhabit the feces and surrounding herbage.

Lifecycle

  • Direct life cycle (No intermediate host required);
  • Pre-patent period – 7 to 9 weeks;
  • Within the small intestine of the animal, the adult females lay eggs which are then shed into the environment.
  • L1- larvae (non-infective larval stage) are released from the egg once in the environment (can occur within 36 hours of being in the environment).
  • L1- larvae develop to L3- larvae within the environment (this can occur within 5 days if the environmental conditions are suitable).
  • L3- larvae are the infective larval stage.
  • L3-larvae are either directly ingested and are transported to the small intestine or the larvae penetrate the skin and then transported to the lungs via the blood stream, coughed up by the host and swallowed to be transported to the small intestine.
  • Once the L3-larvae reach the small intestine they develop into adults.

Transmission

  • Transmission is by cutaneous penetration and/or ingestion of infective from the pasture. Infection occurs mainly in calves (4 to 12 months of age) in their first grazing season (usually winter) as older cattle (>1 year old) develop immunity with age.

Pathological effects

  • Bunostomum spp are blood-sucking nematodes.
  • Moderate worm burden (100 worms), can cause clinical disease.
  • Severe worm burden (2000 worms), can cause death particularly in younger animals.
  • Cutaneous penetration of the infective larvae can result in mild irritation and affected cattle may stomp and lick at their feet.
  • Larval penetration of the intestinal mucosa can result in mild abdominal discomfort, initial constipation followed by bouts of diarrhea.
  • Whole blood loss leads to anaemia and hypoproteinemia (which edema and anasarca can result).
    • Pallor mucous membranes, increased heart rate, respiratory rate, exercise intolerance and weak.
  • Most affected animals appear ill-thrifty.

Other Host Effects

  • Infective larval penetration of the skin may introduce secondary bacterial pathogens.

Control

Control via chemotherapies

  • Numerous broad spectrum anthelmintics are effective against adult worms and larvae. The products available will vary depending on the country.
  • Anthelmintics clasess that are effective against adult worms and larvae include:
    • Macrocyclic lactones.
    • Benzimidazoles.
    • Levamisole.

Control via environment

  • Avoidance of areas in the environment that are wet to reduce the likelihood of percutaneous infection of the infective larval stage.
  • Avoid overstocking pens and paddocks.

Vaccination

  • No vaccines are available.

Other countermeasures

  • Alternative countermeasures outlined for other nematode worm infections may also help to control Bunostomum spp infections.

Diagnosis

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Further Reading

Publications

Refereed Papers

  • Recent references from PubMed and VetMedResource.
  • Van Wyk J A & Mayhew E (2013) Morphological identification of parasitic nematode infective larvae of small ruminants and cattle: A practical lab guide. Onderstepoort J Vet Res 80(1), 1-14 PubMed.
  • Leite A C R (1992) Ultrastructure of the adults of Bunostomum phlebotomum (Nematoda: Ancylostomatidae). Memórias do Instituto Oswaldo Cruz 87, 117-122.
  • Mayhew R L (1950) Studies on Bovine Gastro-intestinal Parasites XV. The Length of Life of the Adult Nodular Worm and Hook Worm in the Calf. American Midland Naturalist 62-65.
  • Sprent J F A (1946) Studies on the life-history of Bunostomum phlebotomum (Railliet, 1900), a hookworm parasite of cattle. Parasitology 37(3-4), 192-201.
  • Schwartz B (1924) Preparasitic stages in the life history of the cattle hookworm (Bustomum phlebotomum). Journal of Agricultural Research 29(9).

Other sources of information


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