Severe Babesiosis With Lyme Disease and Anaplasma Phagocytophilum Coinfection in a Dialysis-Dependent Patient Without Rash or Organomegaly

Babesiosis is a tick-borne intraerythrocytic protozoal infection endemic to the northeastern United States. Coinfection with other Ixodes-transmitted pathogens may occur due to shared vector exposure, although confirmed triple infection remains uncommon. Severe babesiosis, defined by parasitemia ≥10% or evidence of organ dysfunction, may present atypically in immunocompromised individuals. A 73-year-old man with end-stage renal disease on hemodialysis presented with two weeks of cyclic fevers, chills, and weakness after hiking in upstate New York. Physical examination revealed asterixis without rash, jaundice, or organomegaly. Laboratory evaluation demonstrated hemoglobin 6.9 g/dL, platelet count 124 K/µL, lactate dehydrogenase 709 U/L, and 13% parasitemia on peripheral smear. Polymerase chain reaction confirmed Babesia microti. Serologic testing revealed positive Lyme IgG and IgM antibodies and elevated Anaplasma phagocytophilum IgG titers. The patient was treated with azithromycin, atovaquone, and doxycycline, resulting in parasitemia clearance by hospital day 7 without exchange transfusion. Severe babesiosis with Ixodes-borne coinfection may occur without classic findings such as rash or hepatosplenomegaly, particularly in dialysis-dependent patients. Persistent fever in endemic regions despite doxycycline therapy should prompt evaluation for babesiosis. Early recognition and individualized management may prevent invasive interventions.