Incubation Period for Anaplasmosis
Symptoms of anaplasmosis typically appear 5–14 days after the bite of an infected tick. 1
Timing of Symptom Onset
The incubation period for anaplasmosis is consistently reported as 5–14 days following tick bite across authoritative CDC guidelines 1, 2, 3 and recent research 4. This represents the time from initial infection to the development of clinical symptoms.
Clinical Presentation After Incubation
Once symptoms develop, patients typically present with:
Patients with anaplasmosis typically seek medical care 4–8 days after symptom onset, which is later than patients with other tickborne rickettsial diseases who present 2–4 days after symptom onset 1.
Important Clinical Caveats
Rash is uncommon in anaplasmosis, occurring in <10% of patients 1, which distinguishes it from Rocky Mountain Spotted Fever and ehrlichiosis. This absence of rash should not delay diagnosis or treatment.
Gastrointestinal symptoms are less frequent compared to ehrlichiosis, and central nervous system involvement is rare 1.
Transmission Considerations
The bacterium Anaplasma phagocytophilum can be transmitted after 24–48 hours of tick attachment 4, making prompt tick removal within this window potentially protective.
Risk Stratification
Predictors of more severe disease include 1:
- Advanced age
- Immunosuppression
- Comorbid conditions (particularly diabetes)
- Delay in diagnosis and treatment
The case-fatality rate is <1% among patients who seek healthcare 1, but approximately 7% of hospitalized patients require ICU admission 1.