The daughter forms of the parasite that are released then infect other red blood cells, and the cycle continues. The incubation period is 1 to 6 weeks. A sudden or gradual onset of chills and fever is preceded by malaise, muscle aches, and fatigue. Jaundice , dark urine, nausea, and vomiting occur as blood cells rupture and release free hemoglobin into the bloodstream hemolysis. Fulminant, even fatal cases rarely occur, most often in patients who have had the spleen removed or have a non-functional spleen.
Complete recovery occurs in several weeks, with or without antibiotics.
Babesiosis may be underdiagnosed in children since it is generally less severe than in adults. Babesiosis is to be suspected in febrile children with a history of a tick bite who live in or have traveled to an endemic area or have had a recent blood transfusion. It is usually diagnosed by microscopic identification of the parasites in a blood smear. The possibiity of co-infection with Lyme disease should be considered as well, because the two organisms share the same tick vector. The recommended therapy for babesiosis is clindamycin and quinine in combination for 5 to 10 days.