Canis ISSN: 2398-2942


Synonym(s): Piroplasmosis

Contributor(s): Stephen Barr, Maggie Fisher, Alex Morrow, Bryn Tennant, Ian Wright


  • A serious tick-borne protozoan disease caused by Babesia species.
  • Signs: acute to chronic - fever, anemia, hemoglobinuria and jaundice.
  • Susceptible dogs imported into endemic areas are particularly at risk and can die within a day of the appearance of signs.
  • Diagnosis: signs, examination of blood smears, serology, PCR.
  • Concurrent infection with E. canis Ehrlichia canis likely in the US and Southern Europe.
  • Treatment: diminazene aceturate, imidocarb dipropionate or phenamidine isethionate, clindamycin, doxycycline.
  • Prognosis: good if treatment started early, guarded if severe complications.
Print off the owner factsheet on Babesiosis Babesiosis to give to your client.



  • Two species of Babesia are involved:
    • Babesia canis Babesia canis - occurs worldwide in favorable climatic conditions for the survival of the tick vectors.
  • Three strains/subtypes now considered to exist:
    • Babesia canis canis, transmitted by Dermacentor reticulatus Dermacentor reticulatus , is the predominant type in Europe (causes moderately severe disease).
    • Babesia canis vogeli, transmitted by Rhipicephalus sanguineus, in Northern Africa and North America (causes mild disease).
    • Babesia canis rossi, transmitted by Hemophysalis leachi, in Southern Africa (casues severe disease).
  • ?Hyalomma marginatum and Dermacentor anderson may also be involved in the transmission ofB. canis.
  • Babesia gibsoni which causes a more chronic form of the disease, occurs in North America, North and East Africa and Asia including India, Japan and parts of China and is transmitted byRhipicephalus sanguineus Rhipicephalus sanguineus.

Predisposing factors

  • Age and immune status of the dog.
  • Virulence of the strain of the parasite - B. canis rossi causes a more severe disease than B. canis vogeli.
  • Young dogs.
  • Imported dogs.
  • Stress.
  • Immunosuppression.
  • Concurrent disease.
  • Splenectomy Splenectomy.


  • Infestation with vector ticks.


  • Babesiosis is a tick-transmitted protozoal infection in which parasitized erythrocytes rupture and the inflammatory response results in damage to vascular endothelium.
  • The varied clinical manifestations relate to the occurrence of hemolytic disease (acute or chronic) and multi-organ dysfunction in complicated cases.
  • Ticks acquire the piroplasms when they ingest blood from an infected dog.
  • Babesia reproduce both sexually and asexually in the tick and can be passed transovarially and transtadially.
  • Sporozoites, the infective stage, form in the salivary gland and are transmitted during feeding.
  • Parasitized erythrocytes rupture or are removed by phagocytosis, intravascular and extravascular hemolysis and erythrocyte phagocytosis → hemoglobinuria Hemoglobinuria , bilirubinuria and jaundice while the inflammatory response contributes to endothelial damage.
  • The hemolytic crisis → regenerative anemia, hypoxia and metabolic acidosis.
  • Single organ dysfunction tends to predominate although multiple organs are often affected.
  • Cerebral signs occur from sludging of parasitized erythrocytes in small blood vessels or metabolic changes.
  • Severely affected dogs can die before anemia develops.
  • The pathology of canine babesiosis is that of anemia varying from a marked rapidly developing type in highly susceptible dogs to a more chronic manifestation, with jaundice, in dogs reared in endemic areas.
  • A carrier state occurs in recovered dogs.


  • Ticks feed for up to 3 days before they transmit the infection.
  • Incubation period of 10-20 days.
  • The course in peracute cases can be <24 hours.


  • Babesia canis is transmitted by ticks of genera RhipicephalusDermacentorHyalomma and Hemaphysalis with R. sanguineus being the principal vector in most parts of the world.
  • Babesia gibsoni is transmitted by ticks of the genera Rhipicephalus and Hemaphysalis (especiallyR. sanguineus and H. bispinosa).
  • A carrier state state occurs in recovered dogs - thus providing a reservoir of infection.


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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Swainsbury C, Bengtson G & Hill P (2016) Babesiosis in dogs. Vet Rec 178, 172 PubMed.
  • Holm L P, Kerr M G, Trees A J, McGarry J W, Munro E R & Shaw S E (2006) Fatal babesiosis in an untravelled British dog. Vet Rec 159, 179-180 PubMed.
  • Matjila P T, Penzhorn B L, Bekker C P, Nijhof A M & Jongejan F (2004) Confirmation of occurrence of Babesia canis vogeli in domestic dogs in South Africa. Vet Parasitol 122, 119-125 PubMed.
  • Lobetti R G (1998) Canine Babesiosis. Comp Cont Educ Pract Vet 20 (4), 418-431 VetMedResource.