Not all trophozoites are malaria: A case of babesiosis in a traveler from the USA.

Babesiosis, a tick-borne disease caused by protozoa of the genus Babesia, is endemic in North America, but rarely reported in Europe. We report a case involving a splenectomised 72-year-old man from New Hampshire, USA, who was admitted at Careggi University Hospital (Florence, Italy), complaining of a febrile syndrome appeared during a trip to central Italy. After the laboratory flagged the presence of intra-erythrocytic ring-shaped elements, malaria was initially suspected but subsequently excluded by molecular testing. Based on epidemiological and clinical history, Babesia microti infection was suspected and confirmed by molecular test on peripheral blood. Oral atovaquone and intravenous azithromycin were administered for 7 days, switched to oral therapy following clinical improvement and parasitemia clearance. In non-endemic regions, the typical clinical features of this case might not raise suspicion. Nevertheless, rapid diagnosis and treatment are key to ensure favorable clinical outcomes, since babesiosis can cause rapidly aggravating illness, particularly in splenectomised patients.