ISSN 2398-2942      

Ehrlichia canis


Melissa Kennedy

Synonym(s): E. canis




  • Order: Rickettsiales.
  • Family: Rickettsiaceae.
  • Tribe: Ehrlichieae.
  • Genus: Ehrlichia.


  • Ehrlichia: named after Paul Ehrlich, a German bacteriologist.

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Clinical Effects



  • Vector and reservoir is the brown dog tick Rhipicephalus sanguineus.
  • Dogs and other canine hosts may remain bacteremic for years.


  • The organisms form pleomorphic 'elementary bodies' in phagosomes within canine mononuclear cells.
  • Elementary bodies grow and divide by binary fission within the phagosome for 2-3 days.
  • Up to 50 elementary bodies are seen in the mature inclusion (the morula).
  • The contents are released into the blood on lysis of the cell.
  • The organisms are then phagocytosed by other leukocytes.


Pathological effects

  • Canine ehrlichiosis Ehrlichiosis is a febrile disease with lymphadenopathy, nasal and ocular discharges, anorexia, loss of weight and depression.
  • Primary lesion is vasculitis.
  • Causes pancytopenia and a raised erythrocyte sedimentation rate.
  • Thrombocytopenia as a result of consumption, decreased half-life; also decreased platelet function; leads to bleeding tendency.
  • A severe hemorrhagic form may develop 60 days or more after infection. This is associated with aplastic anemia and is sometimes known as 'tropical canine pancytopenia'. Certain breeds, eg the German Shepherd dog German Shepherd Dog , are more susceptible to severe disease.

Other Host Effects

  • Infection may be very mild and go unrecognized.


Control via chemotherapies

Control via environment

  • Tick control.


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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Suksawat J, Hegarty B C, Breitschwerdt E B (2000) Seroprevalence of Ehrlichia canis, Ehrlichia equi and Ehrlichia risticii in sick dogs from North Carolina and Virginia. J Vet Intern Med 14 (1), 50-55 PubMed.
  • Harrus S, Kass P H, Klement E et al (1997) Canine monocytic ehrlichiosis - a retrospective study of 100 cases, and an epidemiological investigation of prognostic indicators for the disease. Vet Rec 141 (14), 360-363 PubMed.
  • Cadman H F, Kelly P J, Matthewman L A et al (1994) Comparison of the dot-blot enzyme linked immunoassay with immunofluorescence for detecting antibodies to Ehrlichia canis. Vet Rec 135 (15), 362 PubMed.
  • Iqbal Z & Rikihisa Y (1994) Application of the polymerase chain reaction for the detection of Ehrlichia canis in tissues of dogs. Vet Microbiol 42 (4), 281-287 PubMed.
  • Matthewman L A, Kelly P J, Bobade P A et al (1993) Infections with Babesia canis and Ehrlichia canis in dogs in Zimbabwe. Vet Rec 133 (14), 344-346 PubMed.

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