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Babesiosis is a tick-borne multisystem disease caused by the intraerythrocytic protozoan parasites of the Babesia species, primarily Babesia microti.
The pathophysiology of babesiosis involves the transmission of Babesia microti by the blacklegged tick, Ixodes scapularis. Once in the host, the parasite invades and multiplies within RBCs, leading to hemolytic anemia and potential organ damage due to the destruction of these cells.
More than 2000 cases of babesiosis are reported annually in the US.
The clinical course of babesiosis can range from being asymptomatic to severe. Common symptoms include fever, fatigue, chills, and diaphoresis. In severe cases, particularly in older or immunocompromised individuals, babesiosis can develop into a serious malaria-like illness that can be fatal without prompt treatment.. Severe cases can lead to complications such as organ damage or failure.
Prognosis and risk of recurrence
The prognosis of babesiosis is generally favorable in normal individuals, with most patients recovering with appropriate treatment. However, the disease can be severe and potentially fatal in high-risk groups, such as the elderly, immunocompromised individuals, or those with other underlying health conditions.
The following summarized guidelines for the evaluation and management of babesiosis are prepared by our editorial team based on guidelines from the Infectious Diseases Society of America (IDSA 2021).
Obtain peripheral blood smear or PCR rather than antibody testing for diagnostic confirmation of acute babesiosis.
Obtain peripheral blood smear or PCR testing in patients with a positive Babesia antibody test to confirm the diagnosis of babesiosis before treatment is considered.
Antimicrobial therapy: offer one of the following combinations for the treatment of patients with babesiosis:
atovaquone and azithromycin
clindamycin and quinine
Red blood cell exchange transfusion: consider performing RBC exchange transfusion in selected patients with severe babesiosis.
4.Follow-up and surveillance
Monitor for Babesia parasitemia using peripheral blood smears in immunocompetent patients during treatment of acute illness. Do not test for parasitemia once symptoms have resolved.
Consider monitoring for Babesia parasitemia using peripheral blood smears in immunocompromised patients even after they become asymptomatic and until blood smears are negative. Consider PCR testing if blood smears have become negative but symptoms persist.