Seroprevalence of scrub typhus among reported acute febrile illness
The objective of the study is to determine the seroprevalence of scrub typhus among patients presenting with acute febrile illness at a tertiary care hospital in Southern Rajasthan and to evaluate the diagnostic utility of immunoglobulin M (IgM) enzyme-linked immunosorbent assay (ELISA) in relation to seasonal patterns, clinical presentation, and laboratory parameters. A retrospective cross-sectional study was conducted in the Department of Microbiology from January to December 2025. Serum samples obtained from patients presenting with acute febrile illness were tested for Orientia tsutsugamushi IgM antibodies using ELISA. Out of 5,783 suspected cases, 661 (11.43%) tested positive for scrub typhus. Seropositivity was higher among males (405; 61.27%) compared to females (256; 38.73%). The highest number of cases was observed during the monsoon and post-monsoon months, particularly in August and September. Fever was the most common presenting symptom among affected patients. IgM ELISA serves as a reliable and practical diagnostic tool for the detection of scrub typhus. The study demonstrates a clear seasonal increase in cases during the monsoon period, highlighting the importance of early diagnosis and increased clinical awareness in endemic regions.