Distribution of B. bovis.
While Babesia infections in animals, B. bovis, are distributed globally, B. microti infections occur mainly in coastal areas in the northeastern United States,
especially the offshore islands of New York, Rhode Island and Massachusetts; and the nearby mainland, including Connecticut. Cases have also been reported from Wisconsin,
Minnesota, Virginia, Maryland, Georgia, and Mexico. Babesia isolates from patients in Washington and California have been characterized as WA-1-type parasites, which are
genetically and antigenically distinct from B. microti. Yet another strain has been isolated in Missouri. In Europe, B. divergens has been responsible for most cases of
babesiosis; most of these infections were in Yugoslavia, Russia, France, the United Kingdom, and Ireland.