Infectious diseases Internal Medicine

Anaplasmosis (Ehrlichiosis)

Anaplasmosis. Wright-Giemsa-stained peripheral blood smear of Anaplasma phagocytophilum

Introduction – Anaplasmosis

Human granulocytic anaplasmosis is caused by an intracellularly (granulocytic) growing gram-negative bacterium formerly known as Ehrlichia, but now renamed to Anaplasma phagocytophilum.

Various types of anaplasmoses are well-known causes of fever in horses, dogs, cats and cattle, with many veterinary cases in the world. They do not transmit person to person.

The disease is spread through tick bites and occurs in areas that are endemic to other tick-borne infections. Double infection with borrelia is reported. Only a few cases are detected. Many infections are mild and self-resolving. The infection is difficult to diagnose and is often overlooked.

It is is not required to report cases of anaplasmosis to local public health authorities.

Symptoms and Clinical Findings – Anaplasmosis

  • Fever, chills, night sweats (about 10-14 days without treatment)
  • Headache
  • Myalgia
  • Tiredness
  • Malaise
  • Nausea, vomiting, abdominal pain, diarrhea, cough, neurological symptoms, redness may also occur.

Complications – Anaplasmosis

  • Prolonged fatigue can occur.
  • Even without treatment, most people recover without complications.


  • Clinically difficult diagnosis
  • Serology becomes positive only after 1-2 weeks of illness. Take a convalescent serum test 4 weeks after the disease onset.
  • In blood smears, intracellular inclusions (morulas) can sometimes be seen.
  • Leukopenia (moderate)
  • Thrombocytopenia (moderate)
  • Liver transaminase + LD increase
  • Mild anemia
  • SR elevated
  • CRP (usually 30-150 mg/L)

Incubation Period

  • 7-10 days

Differential Diagnoses – Anaplasmosis

  • Viruses, such as CMV, mononucleosis
  • Tularemia
  • Malignancies


  • Protective clothing in the forest.
  • Inspection of the body and removal of ticks after an excursion to the woods.

Treatment – Anaplasmosis

  • Doxycycline (Doxyferm, Doxycycline EQL Pharma) 100 mg 2 x 1 per os for 10-14 days.
    Treatment should be effective after a few days if the diagnosis is correct.

Further Reading