Clinical Features and Etiological Profile of Acute Undifferentiated Febrile Illness in Western Maharashtra: A 2024 Monsoon Observational Study

Abstract Background: Acute undifferentiated febrile illness (AUFI) poses diagnostic challenges due to diverse etiologies and nonspecific clinical features, particularly in resource-limited settings like India. Seasonal surges and overlapping symptoms complicate management. This study examined the clinical presentation, laboratory findings, and etiological profile of AUFI cases during the monsoon season at a tertiary care hospital in Western Maharashtra. Methodology: A prospective observational study was conducted from June to September 2024, including 403 patients aged 19–64 years with fever ≥101°F lasting 2–14 days without a clear infection focus. Diagnostics included blood counts, liver and renal function tests, serologies for dengue and chikungunya, and polymerase chain reaction-based tropical fever panel testing for inconclusive cases. Patients were managed per standard protocols, with clinical and laboratory trends analyzed. Results: Dengue (38%) and chikungunya (17%) were the most common causes of AUFI, followed by enteric fever (10%), malaria (7%), leptospirosis (2.8%), and scrub typhus (1.2%). Viral infections accounted for over half of the cases. Common symptoms included body ache (96%) and headache (75%), whereas thrombocytopenia (65%), elevated transaminases (48%), and lymphopenia (33%) were frequent findings. Skin rashes (59%) were primarily associated with dengue and chikungunya. Complications included chikungunya-associated arthritis and bleeding in 23% of cases, mostly due to dengue. The mortality rate was 0.74%, with deaths from severe dengue and chikungunya encephalitis. Conclusion: Dengue and chikungunya dominated AUFI cases during the monsoon in Western Maharashtra. Early diagnosis, region-specific surveillance, rapid diagnostics, and strengthened healthcare infrastructure are essential to reduce AUFI’s burden.