Management of human babesiosis - approaches and perspectives.

Introduction: Human babesiosis is an emerging tick-borne disease caused by intraerythrocytic Babesia protozoa. Most cases are due to Babesia microti, which is endemic in the northeastern and upper Midwestern United States. Other Babesia spp. cases are endemic in China and/or sporadically reported in the United States, Europe, Asia, and elsewhere in the Northern Hemisphere. Cases in immunocompetent hosts are typically mild to moderate, while disease in immunocompromised hosts is often severe.

Areas covered: A historical perspective of compounds that are effective against Babesia spp. is provided. The current management of mild, moderate, and severe babesiosis is discussed, as is the genetic basis of antimicrobial resistance associated with relapsing babesiosis. The use of red blood cell exchange transfusion is reviewed.

Expert opinion/commentary: Most cases of human babesiosis are successfully treated with atovaquone plus azithromycin or clindamycin plus quinine. A major research topic is the management of immunocompromised hosts, especially those experiencing severe or relapsing babesiosis. Two immediate goals are, (i) to develop new antimicrobial agents that target Babesia spp. through novel mechanisms and can overcome resistance to currently recommended antimicrobial agents and, (ii) to gain a better understanding of the efficacy of red blood cell exchange transfusion and indications for its use.