Autoimmune Hemolytic Anemia Secondary to Dual Infection with Scrub Typhus and Plasmodium falciparum Malaria: A Case Report

Early identification of hemolytic anemia in dual infections is essential, as it may worsen outcomes.Effective management includes doxycycline or azithromycin for scrub typhus, 5 artemisininbased therapy for malaria, 6 and immunosuppressive treatment when autoimmune hemolysis is present.7 Only a few cases of scrub typhus-induced autoimmune hemolytic anemia (AIHA) have been documented, particularly in the setting of malaria coinfection, IntroductIonScrub typhus is an acute febrile illness caused by Orientia tsutsugamushi, an intracellular gram-negative bacterium transmitted by infected chigger mites (Leptotrombidium species).1 It is endemic within the "tsutsugamushi triangle," which spans northern Japan and Russia to northern Australia and westward to Pakistan, including much of South and Southeast Asia.Typical clinical features include fever, headache, myalgia, rash, and occasionally an eschar at the bite site. 2 Hematological abnormalities such as thrombocytopenia, leukocyte count variations, and mild anemia are common, but hemolytic anemia is rare.The mechanisms proposed for scrub typhusrelated hemolysis include immune-mediated destruction through autoantibodies, endothelial injury, cytokine-driven hemophagocytosis, and oxidative stress on red blood cells (RBCs). 1 Plasmodium falciparum malaria also produces hemolytic anemia via direct parasitization, splenic clearance, and immune-mediated injury, including autoantibodies such as antiphosphatidylserine antibodies.3 Although coinfection with scrub typhus and malaria has been reported in endemic areas, it remains uncommon, with a pooled prevalence of around 1% among febrile patients.