
This parasitic disease of the red blood cells can be found worldwide, however most documented cases have been found in the United States. Most human infections are attributed to the species, Babesia microti, while other species are less often seen in zoonotic infections.
It is seen most frequently in the Northeast (Connecticut, Massachusetts, New Jersey, New York and Rhode Island) and to a lesser extent in the upper Midwest (Minnesota and Wisconsin).
The parasite is typically transmitted through a tick bite, Ixodes scapularis in the U.S., from late spring to early fall.
It can also be transmitted through blood transfusions and this is not restricted by geographical regions.
Depending on host factors (people without a spleen, immunocompromised) the disease can range from asymptomatic to life threatening.
Symptoms if present typically appear as non-specific flu like symptoms, fever, chills, body aches, and hemolytic anemia.
The danger for donated blood is that even asymptomatic people may have low-level amount of Babesia in the bloodstream from months to longer than a year making blood transfusion infections an issue. Tests for screening blood donors for Babesia are not available.
After getting infected, the presence of symptoms is variable depending on the host and parasite factors. Typically after tick borne transmission symptoms appear in one to three weeks and it may be weeks to months post blood transfusion.
Laboratory diagnosis of acute cases is by identifying the parasite within red blood cells microscopically. It is sometime difficult to differentiate from the malaria parasite (Plasmodium falciparum).
A combination therapy of clindamycin and quinine is standard care for severe infection. Also coinfections with lyme disease or anaplasmosis should be considered.
If you live in Babesia endemic areas, prevention is through rodent control (deer mice and other small mammals) and the use of tick repellent.