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Babesiosis in humans is a rare, potentially fatal disease that is transmitted by the bite of an infected tick. Babesiosis is a common infection in animals.
Babesiosis is caused by the Babesia parasite.
Babesiosis occurs mainly in coastal areas in the northeastern United States, especially the offshore islands of New York and Massachusetts. Cases have also been reported in Wisconsin, California, Georgia, and in some European countries.
Babesiosis is most commonly spread to people by the bite of a tick infected with the Babesia parasite. Babesiosis is spread by deer ticks, which are carried mainly by deer, meadow moles and mice. Deer ticks also spread Lyme disease. People can be infected with both Babesiosis and Lyme disease at the same time. People can also get Babesiosis from a contaminated blood transfusion.
The parasite attacks the red blood cells. Symptoms, if any, begin with tiredness, loss of appetite, and a general ill feeling. As the infection progresses, these symptoms are followed by fever, drenching sweats, muscle aches, and headache. The symptoms can last from several days to several months.
It can take from 1 to 12 months for the first symptoms to appear, but less time for persons with weakened immune systems.
Laboratory diagnosis is based on identifying the parasite in red blood cells.
Anyone can get Babesiosis, but some people are at increased risk for severe disease:
Complications include very low blood pressure, liver problems, severe hemolytic anemia (a breakdown of red blood cells) and kidney failure. Complications and death are most common in persons whose spleens have been removed. Other people usually have a milder illness and often get better on their own.
A combination of anti-parasite medicines can be effective in treating Babesiosis.
It is not known how common Babesiosis is in the United States. Most people have no symptoms, and those who do are usually older persons and people who are already sick with other conditions. Most causes occur during spring, summer, and fall.
Yes. The first case was reported from Nantucket Island, Massachusetts, in 1969. Since then, Babesiosis has emerged as a health threat in the United States, with increasing reports of Babesiosis symptoms and some deaths in areas where the risk of infection was not previously recognized.
No vaccine is available to protect humans against Babesiosis. You can reduce your risk by taking these precautions against tick bites.