Tropical and Arboviral Causes of Febrile Illness in International Travelers: A Focused Review

Background/Objectives: Febrile illness in returning travelers presents a diagnostic and operational challenge for emergency medicine clinicians as early symptoms of high-consequence tropical infections often overlap with common viral syndromes. This review synthesizes current evidence to guide frontline clinicians in the systematic evaluation, diagnosis, and management of internally acquired febrile illnesses with a focus on pathogen of greatest relevance to United States (US) emergency departments (ED). Methods: We conducted a narrative review of the literature addressing epidemiology, clinical presentation, diagnostic testing, and management strategies for key travel-associated infections. Special consideration was given to rapid diagnostic modalities, pediatric risk factors, and infections most frequently implicated in returning travelers, including chikungunya (CHIK), dengue virus (DENV) disease, Ebola virus (EBV) disease, malaria, Mpox, typhoid fever (TF), yellow fever (YF), and Zika virus (ZIKV) disease. Results: Effective evaluation begins with a detailed travel and exposure history, recognition of epidemiologic and clinical red flags, and targeted use of rapid diagnostic tests. Malaria remains the most common life-threatening cause of post-travel fever and the only pathogen with reliable Food and Drug Administration (FDA)-cleared rapid testing available in the ED. Arboviral infections such as DENV, CHIK, ZIKV, and YFrequire region-specific consideration and phase-appropriate molecular or serologic evaluation. Emerging and high-consequence pathogens, including Mpox and EBV, necessitate strict infection control measures and coordination with public health authorities. Pediatric travelers, particularly those visiting friends and relatives, face disproportionate risk for severe systemic infections and often require broader diagnostic testing. Conclusions: A structured approach integrating travel history, focused examination, rapid diagnostics, and early recognition of high-risk features is essential to improving outcomes for febrile returning travelers. Strengthened vector control, enhanced vaccination uptake, and global surveillance are critical to reducing future disease burden.