What is ehrlichiosis in dogs?
Canine ehrlichiosis is an infectious disease caused by the intracellular bacterium Ehrlichia canis, transmitted mainly by the brown dog tick (Rhipicephalus sanguineus). It is one of the most common tick-borne diseases in southern Europe, particularly in Spain, Portugal, Italy and Greece.
Disease phases
- Acute phase (1–4 weeks after exposure): fever, lethargy, loss of appetite, swollen lymph nodes and nasal/ocular discharge. Blood tests show thrombocytopenia (low platelets).
- Subclinical phase: the dog appears to have recovered but the bacterium persists. This phase can last months or years.
- Chronic phase: the most dangerous. Severe anaemia, spontaneous bleeding, weight loss, kidney failure and neurological signs. Can be fatal without treatment.
Symptoms
- Fever (>39.5 °C / 103.1 °F)
- Lethargy and loss of appetite
- Petechiae (small red dots on gums), spontaneous bruising
- Nosebleeds (epistaxis)
- Weight loss and muscle wasting
- Eye inflammation (uveitis)
Diagnosis
- Full blood count: thrombocytopenia + leucopenia + anaemia (the classic triad).
- Serology (ELISA/IFA): detects anti-Ehrlichia antibodies. A negative result very early in the acute phase does not rule out infection.
- PCR: detects bacterial DNA in blood; most useful in the acute phase.
Treatment
- Doxycycline: antibiotic of choice (10 mg/kg/day oral, 28 days). A full course is essential — relapses are common with shorter treatment. Always administer with food to avoid oesophageal irritation.
- Corticosteroids: for severe immune-mediated thrombocytopenia.
- Supportive care: IV fluids, blood transfusions for severe anaemia, gastroprotection.
Dogs treated in the acute phase typically improve within 24–48 hours. Chronic-phase cases carry a more guarded prognosis.
Prevention
- Reliable tick prevention: spot-ons, collars (Seresto®) or tablets (Bravecto®, NexGard®, Simparica®) — renewed on schedule.
- Check your dog (and yourself) thoroughly for ticks after every walk in long grass or scrubland.
- Remove ticks as quickly as possible using fine-tipped tweezers, pulling straight out without twisting.