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This information is provided by Provet for educational purposes only.

You should seek the advice of your veterinarian if your pet is ill as only he or she can correctly advise on the diagnosis and recommend the treatment that is most appropriate for your pet.

Ehrlichia  are transmissible from animals to humans, and so Ehrlichiosis is  a Zoonotic disease

NEWS FLASH During  2013 2 dogs in SE England that have never been abroad or been in contact with dogs that have, have been reported to be infected with Ehrlichiosis. This suggests that we now have infected ticks in our environment.

Ehrlichiosis is caused by an intracellular Rickettsial parasite that is transmitted by tick bites.

 Ehrlichial species usually infect one or more of three types of cell within the body :

  • Monocytes
  • Granulocytes
  • Thrombocytes

There is one species that infects other cells in cattle.

At least seven species have been reported to infect dogs, but in the UK the most likely species to be seen in imported dogs  include :

  • E.canis - worldwide - infect monocytes
  • E.phagocytophila - Britain, Europe, Africa and Asia - infect granulocyytes - "tick-borne fever"

Following transmission of the organism from the saliva of an infected tick there is an incubation period during which the organism spreads in the body's cells and this can last between 1-3 weeks. 

Ehrlichiosis results in multiple organ system involvement and clinical signs vary from very mild to severe  non-specific signs :

  • Anorexia
  • Changes in eye colour - sometimes more severe eye disease eg uveitis, retinal haemorrhage/detachment
  • Depression
  • Enlarged lymph nodes
  • Increase in body temperature
  • Oculonasal discharge - sometimes epistaxis
  • Meningitis - many neurological disorders can occur including  ataxia, cerebellar signs, hyperaesthesia, seizures, tremors, vestibular signs
  • Petechial haemorrhages or ecchymoses in the skin - there are also haemorrhages in many internal organs
  • Polyarthritis - intra-articular haemorrhage or immune reaction
  • Splenomegaly
  • Weight loss

or - the dog may show no signs at all - and this subclinical phase can last for months or even years.

On haematology there may be evidence of :

  • anaemia - nonregenerative
  • leukopenia
  • thrombocytopenia
  • lymphocytosis - (granular cells) occurs occasionally 
  • Platelet migration-inhibition factor (PMIF) concentrations are increased

German shepherd dogs are said to be more susceptible to ehrlichiosis and develop pancytopenia.

Ehrlichia organisms are rarely seen on histological examination of cells, but serum antibodies can be detected within 7-28 days of infection using an indirect fluoresecent antibody technique.

In the absence of a vaccine tick control is the only form of prevention.

Treatment for 14 days with  :

  • Doxycycline - 10mg/kg body weight by mouth /day - drug of choice
  • Oxytetracycline - 25mg/kg body weight by mouth twice daily OR 10mg/kg body weight by subcutaneous or intramuscular injection /day
  • Tetracycline - 22mg/kg body weight by mouth twice daily

When necessary other drug therapy may be needed or considered:

  • Fluid replacement
  • Blood transfusion
  • Corticosteroids - if thrombocytopenia is severe

and possibly

  • Erythropoietin
  • Granulocyte colony-stimulating factor 


Updated January 2016