When to suspect and how to monitor babesiosis

In the past decade, cases of babesiosis in humans have been reported with i ncreasing frequency, especially in the northeastern United States. Babesia microti (in the United States) and bovine strains (in Europe) cause most in fections in humans. Most cases are tick-borne, although cases of transfusio n-associated and transplacental/perinatal transmission have also been repor ted. Factors associated with more severe disease include advanced age, prev ious splenectomy and immunodeficient states. Symptoms include high fever, c hills, diaphoresis. weakness, anorexia and headache. Later in the course of the illness, the patient may develop jaundice. Congestive heart failure, r enal failure and acute respiratory distress syndrome are the most common co mplications. Therapy using the combination of quinine sulfate and clindamyc in was the most commonly used treatment; however, atovaquone suspension plu s azithromycin was recently reported an equally effective and less toxic th erapy. Exchange transfusion, together with antibabesial chemotherapy, may b e necessary in critically ill patients.