Tick-borne disease
Anaplasma phagocytophilum
Carried by the same tick as Lyme, and rising sharply across the Northeast.


The pathogen
Anaplasmosis is caused by Anaplasma phagocytophilum, spread by the same blacklegged tick that carries Lyme — so a single bite can pass on more than one infection at once. The bacteria infect a type of white blood cell called a neutrophil.
Carried by
Blacklegged (deer) tick · Ixodes scapularis
Signs & symptoms
Symptoms typically appear 1 to 2 weeks after a bite:
It shares symptoms — and a treatment — with several other tick-borne infections, which is one reason a careful review after a bite matters.
How it spreads
Anaplasmosis is carried by the same blacklegged (deer) tick as Lyme, so a single bite can transmit both at once. Symptoms typically appear one to two weeks after the bite. It is diagnosed and treated once you feel unwell — there is no single-dose prevention for it.
How it’s treated
Anaplasmosis is treated with doxycycline and usually improves within a day or two of starting it. Because it shares symptoms with other tick infections and can affect blood counts and the liver, a symptomatic case needs a physician’s evaluation and often bloodwork. We will route you to the right care.
When to seek care
Get seen quickly for a high fever with confusion, shortness of breath, or unusual bruising or bleeding after a tick bite — anaplasmosis can be severe in older or immunocompromised people.
Prevention
The surest protection is avoiding bites in the first place: use an EPA-registered repellent, treat clothing and gear with permethrin, stay toward the center of trails, and do a full-body tick check after time outdoors — including the scalp, behind the knees, and the waistline. If you find an attached tick, remove it promptly with fine-tipped tweezers, pulling straight up without twisting, and note the date. The sooner it comes off, the lower the risk.

The physician
Board-certified in Internal Medicine — American Board of Internal Medicine. Trained at Brown, Mount Sinai and Johns Hopkins. He reads every case personally.
A licensed physician reviews every case