Babesiosis Fact Sheet

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  • Babesiosis is caused by a microscopic parasite known as Babesia.
  • Babesia parasites infect the red blood cells.
  • The most common cause of babesiosis in humans in the Unites States is Babesia microti.
  • In the United States, babesiosis most commonly occurs in the Northeast and upper Midwest.

Babesiosis is transmitted in nature by the bite of infected ticks

  • Ixodes scapularis, also called the blacklegged (or deer) tick, transmits the infection in nature.
  • I.scapularis can also transmit the bacteria that cause Lyme disease and anaplasmosis.
  • Transmission can also occur in blood products such as blood transfusions.

Some, but not all, people with babesiosis develop symptoms

  • When symptoms do occur, they usually appear 1 week to a few months after a tick bite.
  • Some people develop nonspecific flu-like symptoms, such as fever, chills, sweats, headache, body aches, loss of appetite, nausea, or fatigue.
  • Because Babesia parasites infect and destroy red blood cells, babesiosis can cause hemolytic anemia.
  • Complications can occur and disease is most severe for the elderly, for individuals who are immunocompromised, and for those without a spleen.

Diagnosis and treatment

  • The Babesia parasites can be seen in blood viewed under a microscope.
  • There are other blood tests that can help diagnose babesiosis.
  • See your doctor right away if you think you might have babesiosis.
  • For ill patients, babesiosis usually is treated for at least 7-10 days with a combination of 2 drugs.
  • Make sure you inform your doctor of any recent tick bites.

Keep Ticks Off

  • Ticks are most active from late spring through early fall.
  • Insect repellent containing 20-30% DEET is recommended to prevent tick bites.
  • Repellents with up to 30% DEET can safely be used on children over 2 months of age.
  • Treat clothes with permethrin (don't use permethrin directly on skin).
  • Long pants and long sleeves help keep ticks off of skin, and tucking pant legs into socks and shirts into pants keeps ticks on outside of clothing.
  • Light colored clothing lets you spot ticks more easily.
  • Talk to your veterinarian about tick control products for your pets.
  • When enjoying the outdoors, be aware that wooded or brushy areas with tall grass and leaf litter are prime tick habitat.  Walk in the center of the trail.
  • Check yoruself, your kids and your pets daily for ticks when spending time in tick habitat.
  • Bathe or shower as soon as possible after coming indoors (within 2 hours) to wash off ticks.

To Remove Ticks

  • Use fine-tipped tweezers.
  • Grab the tick close to the skin; do not twist or jerk the tick.
  • Gently pull straight up until all parts of the tick are removed.
  • Wash your hands with soap and water or an alcohol-based rub.
  • Clean the site of the tick bite with soap and water or an antiseptic.
  • Do not use petroleum jelly, a hot match, nail polish, or other products to remove ticks.

For more information on tickborne disease, visit: