Anaplasmosis is a disease caused by the bacterium Anaplasma phagocytophilum. These bacteria are spread to people by tick bites primarily from the blacklegged tick (Ixodes scapularis) and the western blacklegged tick (Ixodes pacificus).

People with anaplasmosis will often have fever, headache, chills, and muscle aches. Doxycycline is the drug of choice for adults and children of all ages with anaplasmosis.

Signs and Symptoms
Signs and symptoms of anaplasmosis typically begin within 1–2 weeks after the bite of an infected tick.
Tick bites are usually painless, and many people do not remember being bitten.
See your healthcare provider if you become ill after having been bitten by a tick or having been in the woods or in areas with high brush where ticks commonly live.

Early Illness:

Early signs and symptoms (days 1-5) are usually mild or moderate and may include:

- Fever, chills
- Severe headache
- Muscle aches
- Nausea, vomiting, diarrhea, loss of appetite

Late Illness:

Rarely, if treatment is delayed or if there are other medical conditions present, anaplasmosis can cause severe illness. Prompt treatment can reduce your risk of developing severe illness.

Signs and symptoms of severe (late stage) illness can include:

- Respiratory failure
- Bleeding problems
- Organ failure
- Death

Risk factors for severe illness:

- Delayed treatment
- Age: being older puts you at risk
- Weakened immune system: People with weakened immune systems (such as those receiving some cancer treatments, individuals with advanced HIV infection, prior organ transplants, or people taking some medications) are at risk for severe illness

Potential treatment:

Please discuss any treatment option with your medical professional. The CDC recommends Doxycycline as antibiotic treatment for anaplasmosis in adults and children of all ages [L].