Causative Agent
Anaplasma phagocytophilum
Type of Organism
Rickettsial Bacterial Species
Length of Attachment for Transmission
10 hours

Initial Symptoms

  • Symptoms may begin within the first 2 weeks of exposure.
  • Flu-like symptoms are most common and include: fever, chills, fatigue, headache, muscle pain, and nausea.
  • In some patients, a rash may occur.
  • Immunocompromised individuals are at a greater risk for more severe symptoms which include trouble breathing, kidney failure and neurological issues.

Diagnosis and Testing

  • Most often, clinical signs and a history of exposure will be the key to diagnosis.
  • The use of Polymerase Chain Reaction (PCR) to detect Anaplasma DNA in the blood can be used for diagnosis and should be performed within the first week of infection.
  • When testing for antibodies specific to Anaplasma, Indirect Immunofluorescence Assays (IFA) are performed on two samples.
  • The first sample is collected within 7 days of infection and will be compared to the second sample collected 2-4 weeks after infection.
  • Anaplasmosis will be diagnosed if the second sample shows the number of antibodies present has increased since the first sample was tested.
  • A false negative is possible in the first 7-10 days of illness and will commonly occur when the first sample is tested.
  • Blood test results of low platelet count, low white blood cell count or elevated liver enzyme levels can assist with diagnosis.

CDC Treatment Recommendation

  • Adults: Doxycycline 100mg every 12 hours.
  • Children: Doxycycline 2.2mg/kg- 2x daily.

*Doxycycline is the most effective prevention of future complications and should be started within the first 5 days of infection for best results. (CDC)

Disease Pathogenesis

  • Anaplasmosis will invade white blood cells and trigger an immune response causing immediate symptoms.
  • Unfortunately, little is known about the specific pathogenesis of Anaplasmosis.
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