Anaplasmosis is a bacterial infection that gets transmitted through the bite of an infected blacklegged tick, the same tick that spreads Lyme disease and babesiosis. Cases have historically been concentrated in the Northeast and Upper Midwest, but recent CDC surveillance shows the disease is now reported across the Southeastern United States, including Florida, Alabama, Georgia, South Carolina, North Carolina, and Virginia. The illness is treatable and most people recover fully, but only if it is recognized and started on antibiotics quickly.
What Anaplasmosis Is
The official name is human granulocytic anaplasmosis (HGA). It is caused by the bacterium Anaplasma phagocytophilum, which infects a type of white blood cell called a neutrophil. It is transmitted by the blacklegged tick (Ixodes scapularis), often called the deer tick in the Southeast.
You only need a tick attached for 24 to 48 hours for transmission to occur, and many patients never see the tick or recall the bite.
Symptoms: What to Watch For
Symptoms typically appear 5 to 14 days after a tick bite and resemble a bad flu. Most people experience:
- Fever and chills
- Severe headache
- Muscle aches and fatigue
- Loss of appetite and nausea
Some patients also develop cough, abdominal pain, confusion, or, less commonly, a rash. Anaplasmosis rarely causes the bullseye rash associated with Lyme disease.
Without treatment, symptoms can progress to respiratory failure, organ damage, abnormal bleeding, or in elderly or immunocompromised patients, death. Early recognition is critical.
How Anaplasmosis Is Diagnosed
Several tests are available, each with a specific role:
| Test | What it shows | Best for |
|---|---|---|
| Routine CBC | Low platelets, low white blood cells, mild anemia | Initial screening when the diagnosis is suspected |
| Liver enzyme panel | Elevated AST and ALT | Confirms systemic illness pattern |
| PCR (blood) | Detects bacterial DNA directly | Best test in the first 1 to 2 weeks of symptoms |
| IFA antibody test (paired) | Four-fold rise in antibodies between acute and convalescent samples | Confirmation, especially when PCR is negative |
| Peripheral blood smear | Morulae visible inside neutrophils | Specialist use, supports diagnosis |
Many providers begin treatment based on clinical suspicion and lab abnormalities before confirmation, because waiting on antibody results can delay care.
If you live in any of the six states we serve and have these symptoms after a known or possible tick bite, schedule with an internal medicine provider who tests for tick-borne disease panels.
Treatment
The treatment of choice is doxycycline, 100 mg by mouth twice a day, typically for 10 to 14 days, or until at least 3 days after fever resolves. Most patients feel substantially better within 24 to 48 hours of starting the antibiotic, which can itself help confirm the diagnosis.
Doxycycline is safe and effective even in children with suspected anaplasmosis. Alternatives like rifampin are sometimes used in patients who cannot take doxycycline, but doxycycline is the first-line choice in nearly all cases.
Severe cases may require hospitalization for IV antibiotics and supportive care, particularly in patients over 65 or those with weakened immune systems.
Co-infections to Consider
Because the blacklegged tick can carry more than one pathogen, anaplasmosis is sometimes diagnosed alongside Lyme disease or babesiosis. If your symptoms are unusually severe, prolonged, or atypical, your provider may order additional tests. Our practice covers tick-borne co-infections as part of our broader Lyme disease workup.
Prevention
Tick avoidance is the only true prevention strategy:
- Wear long sleeves and pants in wooded or grassy areas
- Use EPA-registered repellents (DEET, picaridin) on skin and permethrin on clothing
- Do thorough tick checks after time outdoors
- Shower within two hours of coming inside
- Remove attached ticks promptly with fine-tipped tweezers
- Treat pets with veterinary tick prevention, since they bring ticks indoors
Most ticks in the Southeast are not infected, but the proportion that carry Anaplasma has grown steadily over the past decade.
Frequently Asked Questions
How long after a tick bite do anaplasmosis symptoms appear?
Most commonly between 5 and 14 days. Some patients develop symptoms slightly sooner or later, depending on individual response.
Is anaplasmosis serious?
It can be. Most patients recover with prompt antibiotic treatment, but untreated or delayed cases can lead to organ failure and, rarely, death. Anyone with these flu-like symptoms after potential tick exposure should be evaluated quickly.
Can I get anaplasmosis even if I never saw the tick?
Yes. Many patients never recall a tick bite, especially because nymph-stage ticks are tiny (smaller than a poppy seed).
Will I have lasting effects after treatment?
Most patients fully recover with no long-term effects. A subset experiences ongoing fatigue or muscle aches for weeks after treatment, which usually resolves on its own.
How do I get tested if I think I have anaplasmosis?
Contact our office to schedule. We offer in-office visits in Northeast Florida and telemedicine for patients across the six states we serve.
This article is informational and not a substitute for medical advice. If you have symptoms suggestive of a tick-borne illness, seek medical care promptly.