Babesiosis Download pdf version of this fact sheet

What is babesiosis?

Babesiosis is a rare, serious, and sometimes fatal disease spread by the northern deer tick. Ticks can carry a parasite called Babesia microti that attacks the red blood cells of many animals, including man.

Babesiosis occurs most often in the elderly or in people who already have a problem with their immune system. This disease has been reported during spring, summer, and fall in coastal areas in the northeastern United States. Cases are also reported in Wisconsin, California, Georgia and in some European countries.

How do you get it?

You get the parasite from the bite of an infected deer tick. The tick is carried by meadow voles, mice, deer, cattle, and birds. Babesiosis is not spread person-to person, except by blood transfusions (very, very, rarely).

What are the symptoms of babesiosis?

The symptoms include fever, chills, joint pain, fatigue. These symptoms can last from several days to several months. Sometimes, a person can be infected with the parasite but not show any symptoms.

When do symptoms start?

It may take from 1 to 12 months for first symptoms to appear after infection with the parasite.

What is the treatment for babesiosis?

Effective treatments are available, and most people who are infected with Babesia microti respond well.

Should an infected person be excluded from work or school?

No. Babesiosis is not transmitted person-to-person, except by blood transfusion.

If you get babesiosis once, can you get it again?

Whether or not past infection with babesiosis can protect a person from future infections is unknown.

How can you keep from getting it?

When outdoors in tick-infested areas, use tick repellents. It is also helpful to wear light colored clothing and to tuck the pant legs into socks.

Institute rodent-control measures in areas where people live.

Download pdf version of this fact sheet Download pdf version of this fact sheet

For more information, see the CDC’s website.