Most cases of babesiosis are caused by bites from deer ticks, pictured above on human skin.
CNN  — 

Tickborne disease has been on the rise in the US, with the number of cases growing 25% from 2011 to 2019. Among them is babesiosis, which has become significantly more prevalent in the Northeast in recent years.

Seven states were already considered to have endemic transmission of babesiosis, with consistent presence of the disease: Connecticut, Massachusetts, Minnesota, New Jersey, New York, Rhode Island and Wisconsin. A new report from the US Centers for Disease Control and Prevention added three others to that list – Maine, New Hampshire and Vermont – where case rates have grown the fastest and now match or surpass other states.

In those 10 states, reported cases of babesiosis have increased in all but two: Minnesota and Wisconsin, where case rates were about 30% lower in 2019 than they were in 2011.

Overall, more than 16,000 cases of babesiosis have been reported to the CDC between 2011 and 2019, according to the report.

Symptoms of the disease include fever, muscle and joint pain and headache. Illness can range from mild to severe, and it can be fatal in rare cases. Infections can also be asymptomatic, so patients may not always know to be tested.

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The CDC cautions that the increasing prevalence of babesiosis could pose risks to the blood supply. The disease is transmissible through blood transfusion, and infections acquired this way have shown to have significantly worse outcomes and higher risk of death than those acquired through a tick bite, the report says. The US Food and Drug Administration currently recommends blood donations screening for babesiosis in 14 states and Washington, DC, in and around areas where transmission is endemic.

“Persons spending time outdoors in states with endemic babesiosis should practice tick bite prevention, including wearing long pants, avoiding underbrush and long grass, and using tick repellents,” according to the CDC.