BABESIOSIS IN WISCONSIN - A POTENTIALLY FATAL DISEASE

Babesiosis is emerging as an important tick-borne zoonosis in the Unit ed States. Most reported cases of this parasitic disease have been acq uired in the Northeast. To date, only two clinical cases of Babesia mi croti infection acquired in the upper Midwest have been described. We report eight more cases. Most if not all of the 10 total cases probabl y were acquired in northwestern Wisconsin. Three cases (30% of 10) we now report were fatal and occurred in elderly patients (65-75 years ol d) who died after complicated hospital courses. One patient probably h ad had a latent Babesia infection that activated because of immunosupp ression attributable to high-dose corticosteroid therapy and to spleni c infarctions caused by cholesterol emboli. AII three fatal cases were diagnosed incidentally and highlight the importance of considering th e diagnosis of babesiosis in febrile patients who have been in babesio sis-endemic areas; examining their blood smears carefully; and treatin g promptly with clindamycin and quinine, and, if indicated, exchange t ransfusion. Medical personnel should be knowledgeable about this zoono sis, which is not limited to the northeastern United States, and is po tentially serious, sometimes fatal.