Human Anaplasmosis is induced by the bacterial infection Anaplasma phagocytophilum. The blacklegged tick and the western blacklegged tick are the most common carriers of these microorganisms into humans. The anaplasmosis-causing bacteria typically infect white-footed mice, deer, and other wild animals. When these animals are bitten by a tick, the tick gets sick. A tick infected with the bacterium may transmit it to people. When a tick bites an individual, the germs enter the individual’s bloodstream. 

Typically, the tick must be attached for between 24 and 48 hours and grow bigger (engorged) in order to transmit the illness. Human anaplasmosis is not infectious between individuals. In rare situations, it may be obtained by blood donation or solid organ transplantation. It happens more often in the springtime and summertime. This is when the danger of human interaction with infected ticks is greatest.


Human Anaplasmosis signs and symptoms often appear one to two weeks after the tick bite that caused the infection. Most tick bites are not painful, and many victims don’t even remember the bite. 

If you feel unwell after being bitten by a tick or in wooded or heavily forested areas where ticks are likely to reside, consult your doctor.

Early Illness

Early symptoms (days 1-5), which are often mild or moderate, may include:

  • Severe headache
  • Nausea
  • Fever
  • Muscle aches
  • Loss of appetite
  • Chills
  • Diarrhea 

Late Illness

Rarely, Human Anaplasmosis can result in serious illness if treatment is neglected or if additional medical problems are present. Early medical intervention can lower your risk of suffering from a serious illness.

Severe (late-stage) disease may manifest as the following signs and symptoms:

  • Organ failure
  • Bleeding problems
  • Respiratory failure
  • Death


Your physician will conduct a thorough physical exam and ask about your medical history. Inform them if you have recently been bitten by a tick or if you have been outside in parts of the nation where these ticks are prevalent.

Your healthcare professional will need test results to properly diagnose the illness. Examples of such examinations could be:

  • Microscopical examination of your white blood cells
  • Polymerase chain reaction (PCR)
  • Antibody screening.

Diagnosing anaplasmosis is difficult. Mild symptoms might originate from numerous disorders. Some patients may not know a tick bit them.


Whenever human anaplasmosis is detected, treatment should begin promptly. In certain instances, therapy is initiated based on clinical symptoms before lab testing confirms the diagnosis. This is performed to avoid serious problems.

Antibiotics are the primary therapy. Doxycycline is the most often prescribed antibiotic against bacteria. If you have received prompt treatment and are experiencing relatively moderate symptoms, you may likely take your antibiotics at home. Your fever should subside within a few days. Your other symptoms may last for many weeks. Once eliminated, these symptoms do not return.

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