Concurrent mixed infection with malaria, dengue and scrub typhus in a 5-year-old child: A rare paediatric case report

Diagnosing febrile illnesses in children from tropical regions poses significant clinical challenges due to overlapping symptoms of endemic infections such as malaria, dengue and scrub typhus. Although coinfections are uncommon, they can complicate clinical management and delay targeted therapy. We report the case of a 5-year-old boy of Odisha origin, living in Tamil Nadu, who presented with a seven-day history of high-grade, intermittent fever. Initial clinical and laboratory investigations revealed severe anaemia and thrombocytopenia. Rapid diagnostic tests confirmed co-infection with Plasmodium falciparum, P. vivax and dengue virus. The child received antimalarial drugs and supportive therapy. However, there was limited clinical improvement. Although the characteristic eschar typically associated with scrub typhus was absent, the persistent febrile course and inadequate response to treatment raised clinical suspicion of an additional co-infection. Considering the regional endemicity of scrub typhus, IgM serology was performed and tested positive. The patient was then treated with a combination of antimalarials, doxycycline, and supportive measures, including blood transfusion for anaemia. Marked clinical and haematological improvement occurred within days of initiating the revised treatment plan. This case underscores the need to consider co-infections in paediatric patients presenting with prolonged fever in endemic regions. Early clinical suspicion, prompt diagnostic workup and appropriate therapy are essential for achieving favourable outcomes in such challenging scenarios.