Animals Involved
Rodents, insectivores, lagomorphs, some other mammals; reservoirs uncertain for some species
Known Distributions
Babesia spp worldwide in wild animals, many agents not identified to species; human illness due to B microti complex reported in North America (most), Europe, Asia, Australia
Probable Means of Spreading
Bite of infected Ixodes ticks for B microti
Clinical Manifestations in People
Many immunocompetent patients may have mild to moderate flulike, febrile illness; mild to severe hemolytic anemia, especially severe in immunocompromised and elderly; respiratory, hepatic, renal, and other organ dysfunction; recurrent or chronic infection may develop; dual infection with B burgdorferi may worsen both diseases; death possible in severe cases