Bovis ISSN 2398-2993

Trypanosomiasis

Synonym(s): Trypanosomosis

Contributor(s): Mike Reynolds , Andrew Forbes

Introduction

  • Cause: African Animal Trypanosomosis (AAT) is caused by one of three species of protozoa:
    • Trypanosoma congolense
    • Trypanosoma brucei brucei
    • Trypanosoma vivax.
  • Signs: pyrexia, ill thrift, wasting, lymphadenopathy, anemia, abortion and sudden death.
  • Diagnosis: ELISA, indirect fluorescent antibody test (IFAT), polymerase chain reaction (PCR), confirmation of parasite on impression smears/direct microscopic examination of whole blood.
  • Treatment: diminazene aceturate and quinapyramine methylsulfate are used in clinical disease situations, but resistance to therapy has been encountered.   
  • Prognosis: unless treated most animals will eventually die of the disease.

Pathogenesis

Etiology

  • African Animal Trypanosomosis (AAT) is caused by one of three species of protozoa:
    • Trypanosoma congolense
    • Trypanosoma brucei brucei 
    • Trypanosoma vivax
  • All species are spread via infected tsetse flies of the genus Glossina Cattle flies and larvae: overview.
  • Trypanosoma evansi causes mild clinical disease in cattle and buffalo in endemic regions of northern Africa, Asia, Middle East, and central and southern America.

Predisposing factors

General

  • The presence of infected vectors.
  • The presence of other infected domestic species and wild ungulates which serve as potent sources of infection.

Specific

  • All Trypanosoma species associated with disease are spread via infected tsetse flies of the genus Glossina.
  • Trypanosoma vivax may also be spread by other biting insects, especially tabanids.

Pathophysiology

  • Trypanosomosis is a progressive disease characterized by anemia, tissue damage and immunosuppression.
  • After inoculation through insect feeding, metacyclic trypanosomes multiply at this site causing a local skin reaction. Here the parasite changes to the trypomastigote form and enter the bloodstream either directly or through the lymphatics, causing the clinical signs of anemia and organ damage.

Timecourse

  • 4 days to 5 weeks.

Epidemiology

  • Infection rates in endemic areas can reach 60 % but indigenous breeds of cattle are more tolerant of infection.

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

Other sources of information

  • Soudré A, Ouédraogo-Koné S, Wurzinger M & Müller S, Hanotte O, Ouédraogo A G & Sölkner J (2012) Trypanosomosis: a priority disease in tsetse-challenged areas of Burkina Faso. Trop anim health prod (45), 497–53.


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