Bovis ISSN 2398-2993

Giardia spp

Contributor(s): Mike Taylor , Andrew Forbes

Introduction

Classification

Taxonomy

  • Phylum: Metamonada.
  • Class: Trepamonadea.
  • Order: Giardiida.

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Clinical Effects

Epidemiology

Habitat

  • Inhabit the intestines of mammalian hosts.
  • Cysts may be found in water sources.

Lifecycle

  • The life cycle is simple and direct.
  • Trophozoites divide by binary fission to produce further trophozoites.
  • Trophozoites intermittently encyst forming resistant cyst stages that pass out in the feces.

Transmission

  • Direct animal-to-animal contact and fecal soiling is the most likely method of transmission, although water contamination may be a potential route.

Pathological effects

  • Infection may cause villous atrophy, crypt hypertrophy and an increased number of intraepithelial lymphocytes.
  • Clinical signs often include chronic, diarrhea, weight loss, lethargy and failure to thrive.

Other Host Effects

  • Infections are often subclinical.

Control

Control via chemotherapies

  • There is no recommended treatment for infection in calves.
  • Several benzimidazole anthelmintics (eg albendazole, fenbendazole Fenbendazole) are effective in other host species and may prove to be of benefit.

Control via environment

  • Good hygiene and prevention of fecal contamination of feed and water.

Vaccination

  • There are no vaccines.

Diagnosis

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Further Reading

Publications

Refereed Papers

  • Recent references from PubMed and VetMedResource.
  • Thompson R C A & Monis P (2012) Giardia- From Genome to Proteome. Advances in Parasitology 78, 57-95 PubMed.
  • Plutzer J, Ongerth J & Karanis P (2010) Giardia taxonomy, phylogerny and epidemiology: Facts and open questions. International Journal of Hygiene and Environmental Health 213, 321-333 PubMed.
  • Dixon B, Parrington L, Cook A, Pinta K, Pollari F, Kelton D et al  (2011) The potential for zoonotic transmission of Giardia duodenalis and Cryptosporidium spp. from beef and dairy cattle in Ontario, Canada. Vet Parasitol 175, 20-26 PubMed.
  • Olson M E, O’Handley R M, Ralston B J, McAllister T A & Thompson R C A (2004) Update on Cryptosporidium and Giardia infections in cattle. Trends Parasitol 20, 185-191 PubMed.

Other sources of information

  • Taylor M A, Coop R L, Wall R L (2016) Chapter 8 - Parasites of Cattle: Giardia intestinalis. In: Veterinary Parasitology. 4th edn. John Wiley & Sons, Chichester, West Sussex, UK. pp 375.

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