ISSN 2398-2993      

Theileriosis

obovis
Contributor(s):

Mike Reynolds

Andrew Forbes

Synonym(s): Theileria annulata infection, East coast fever, Tropical fever


Introduction

  • Cause:
    • Theileriae are obligate intracellular protozoan parasites that infect both wild and domestic Bovidae throughout much of the world.
    • Theileria parva is responsible for East Coast Fever in Eastern and Central Africa.
    • Theileria annulata for tropical theilerioses in the Mediterranean countries.
    • Theileria orientalis (Ikeda), clinical disease outbreaks in Asia, Australia and New Zealand.
    • Theileria orientalis (buffeli) has been reported in the UK but is considered non-pathogenic.
  • Signs: see below.
  • Diagnosis: indirect fluorescent antibody test; giemsa stained impression smears form the blood or lymph nodes in live animals, or from most internal organs in necropsies; PCR.
  • Treatment: anti-protozoal drugs, such as buparvaquone, parvaquone, and halofuginone and the antimicrobial oxytetracyline have been advocated.
  • Prognosis: guarded.

Pathogenesis

Predisposing factors

General

  • Naïve cattle introduced into an endemic area.
  • Infected cattle introduced into an uninfected area.
  • Infected ticks transported on cattle into an uninfected area.

Pathophysiology

  • Sporozoites are inoculated via infective ticks into lymphocytes which undergo schizogony and lymphoid proliferation.
  • Further lymphoid proliferation occurs and schizonts differentiate into merozoites and invade nearby erythrocytes.
  • Here they form piroplasms which are the infective form for ticks.

Timecourse

  • The incubation period after infection is 10-25 days.

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.
  • Eamens G J, Bailey G, Gonsalves J R, Jenkins C (2013) Distribution and temporal prevalence of Theileria orientalis major piroplasm surface protein types in eastern Australian cattle herds. Aust Vet J 91, 332-340 PubMed.
  • Izzo M M, Poe I,  Horadagoda N, De Vos A J, House J K (2010) Haemolytic anaemia in cattle in NSW associated with Theileria Infections. Aust Vet J 540, 45-51 PubMed.
  • Taylor M (2000) Protozoal disease in cattle and sheep. In Practice 22, 604-617 PubMed.

Other sources of information

  • OIE technical disease card (2009) Theileriosis. pp 1-6: Website: www.oie.int. Last accessed 20th February 2017.
  • Brown C & Torres A (2008) USAHA Foreign Animal Diseases. Seventh Edition. In:
    Committee of Foreign and Emerging Diseases of the US Animal Health Association. Boca
    Publications Group Inc, Canada. pp 401-404.
  • Radostits O M, Gay C C, Blood D C & Hinchcliff K W (2005) Diseases caused by protozoa. In: Veterinary Medicine. 9th edn. W B Saunders, USA. pp 1324-1329.

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