In spite of its ability to cause serious, and even life-threatening disease, babesiosis is only occasionally fatal. One to 3 weeks after tick bite, malaise, loss of appetite, fatigue, and dark urine are common. Initial symptoms are followed several days later by fever, myalgia, headache, and drenching sweats. Illness can range from a mild self-limited infection to severe hemolytic anemia, renal failure, and severe hypertension. Decreased levels of blood platelets may necessitate exchange blood transfusions.
Most patients have thrombocytopenia.
Wright's or Giemsa-stained blood smears may reveal babesia organisms. Elevated titers can persist for months after acute infection. Most patients have a mild illness and recover without specific treatment. A 7-day regimen of oral quinine plus oral or intravenous clindamycin is recommended. Blood transfusions are given in severe cases.