Equis ISSN 2398-2977

Babesia spp

Contributor(s): Christopher Brown, Susan Dawson, Carla Sommardahl

Introduction

Classification

Taxonomy

  • Phylum:Protozoa.
  • Family:Babesiidae.
  • Class:Piroplasmidia.
  • Genus:Babesia/Theileria.
  • Species:equi,caballi.

Etymology

  • Named after Victor Babes (1854-1926) - Romanian bacteriologist.

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Clinical Effects

Epidemiology

Habitat

  • Carried in ixodid ticks;T. equiandB. caballicarried byDermacentor,HyalommaandRhipicephalusspp.

Lifecycle

  • Transovarian and trans-stadial infection of ticks.
  • Organisms multiply in mammalian red blood cells   →   blood ingested by tick   →   sexual phase in tick gut   →   schizogony   →   vermicules, which migrate to tissues of tick, including ovary   →   multiplication   →   invade eggs   →   multiply in tissues of hatched larvae   →   enter salivary glands of tick   →   infective sporozoites   →   inoculated into new mammalian host during feeding.

Transmission

Pathological effects

  • Immunity due to colostral antibodies allows subclinical infection which confers active immunity.
  • Humans: fever, hemolytic anemia, may be fatal. More common in splenectomized patients.
  • Dog/cat: progressive anemia; may be acute or chronic; often subclinical.
  • Horses:T. equimore pathogenic: causes fever, anemia, jaundice and hemoglobinuria.B. caballiinfections usually associated with pyrexia and anemia only.
  • Pathogenesis: parasites divide in erythrocytes   →   red cell destruction   →   death in acute form within a few days. In milder cases fever, anorexia and jaundice may persist for some days before recovery.

Other Host Effects

  • Subclinical infection occasionally seen in resistant animals or those infected withBabesiaspp of low virulence.

Control

Control via chemotherapies

  • T. equi:
    • Amicarbalide.
    • Imidocarb.
    • Pentamidine.
  • B. caballi:
    • Amicarbalide.
    • Imidocarb.
    • Quinuronium sulfate.

Other countermeasures

  • Control tick vector.

Diagnosis

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Mehlhorn H & Schein E (1998) Redescription of Babesia equi Lavern, 1901 as Theileria equiParasitol Res 84 (6), 467-475 PubMed.
  • Bruning A (1996) Equine piroplasmosis, an update on diagnosis, treatment and prevention. Br Vet J 152 (2), 139-151 PubMed.
  • Dewaal D T (1992) Equine piroplasmosis - a review. Br Vet J 148 (1), 6-14 PubMed.

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