Fatal case of Leptospira wolffii infection in Sikkim, India: An autochthonous case from a new geographical region.

This case report describes the first documented fatal case of Leptospira wolffii in Sikkim, India, marking a novel geographic occurrence of leptospirosis in the Himalayan state. A 40-year-old female presented with fever, sepsis, and acute kidney injury, succumbing despite intensive care and antibiotic treatment. Targeted 16S rRNA sequencing confirmed a 100 % identity with L. wolffii. Phylogenetic analysis showed close relatedness to strains from Thailand, Bangladesh, and Assam. Environmental investigations revealed rodent infestation and livestock proximity as potential sources. This study underscores the need for awareness of leptospirosis in non-endemic regions, rapid diagnostics, and a one health approach to mitigate such outbreaks.