Investigation of Outbreak of Leptospirosis in a Village in Koraput, Odisha, 2024

Background: Leptospirosis outbreaks have risen in India over the past three decades, especially in coastal regions. On September 9, 2022, a cluster of fever with myalgia and diarrhoea was reported in Village X, Koraput district, Odisha. A rapid response team confirmed the outbreak, and an investigation was initiated on September 11. Objectives: Our objective was to describe the event in terms of time, place, and person, and to identify potential sources. Materials and Methods: On confirmation of the outbreak, we diagnosed leptospirosis in seven cases by immunoglobulin M (IgM) enzyme-linked immunosorbent assay (ELISA). We initiated the investigation on September 11 to describe the outbreak and identify its source. We defined a probable case as an individual who reported at least one listed symptom on or after August 9, 2022, and conducted an active surveillance by door-to-door survey. We conducted a descriptive analysis of the reported cases by plotting an epidemiological curve and calculating the attack rate by place and person. Results: We identified 26 cases from September 3 to 17, 2022. The epi-curve indicated a continuous source outbreak. Higher attack rates were observed in low-lying areas, especially Majhi and Harijan Sahi. Adults aged 45–60 years and males were more affected. Most cases reported close contact with livestock and walking barefoot. All seven samples tested were positive for leptospirosis by IgM ELISA. Conclusion: Heavy rainfall and subsequent flooding likely increased rodent infestation, which may have led to the outbreak. Chemoprophylaxis for contacts reduced cases, and chlorination of drinking water was recommended to prevent further outbreaks.