Babesiosis

Babesiosis is an infectious disease caused by intraerythrocytic protozoan parasites of the genus Babesia, transmitted primarily through the bite of infected Ixodes ticks (the same ticks that transmit Lyme disease). The most common species affecting humans are Babesia microti in North America and Babesia divergens in Europe. The disease can also be transmitted through contaminated blood transfusions or, rarely, through congenital (transplacental) transmission. Babesiosis primarily affects the hematologic system, as the parasites invade and destroy red blood cells, leading to hemolytic anemia. Key symptoms include fever, chills, sweats, fatigue, malaise, headache, and myalgia, typically appearing one to four weeks after a tick bite. Laboratory findings commonly reveal hemolytic anemia, thrombocytopenia, elevated liver enzymes, and elevated lactate dehydrogenase. Many infected individuals, particularly those who are immunocompetent, may remain asymptomatic or experience only mild illness. However, the disease can be severe and life-threatening in immunocompromised individuals (especially those who are asplenic, elderly, or receiving immunosuppressive therapy), with complications including acute respiratory distress syndrome, disseminated intravascular coagulation, renal failure, and splenic rupture. Treatment depends on disease severity. For mild to moderate cases, the standard regimen is a combination of atovaquone and azithromycin for 7 to 10 days. For severe cases, the preferred treatment is intravenous clindamycin combined with oral quinine, along with supportive care including red blood cell exchange transfusion in cases of high parasitemia (typically greater than 10%), severe hemolysis, or organ compromise. Immunocompromised patients may require prolonged courses of antimicrobial therapy. Prevention strategies focus on tick avoidance measures and screening of blood donations in endemic areas.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

Common questions about Babesiosis