Background: Annually, an estimated 1.03 million leptospirosis cases lead to 2.9 million disability adjusted life years. A cluster of fever cases was reported in Keerakadu village, Kollihills block in Namakkal district of Tamilnadu state, India, on April 28, 2017. We investigated to control the outbreak. Methods: We did a cross-sectional survey between April 29 and May 1. We defined a case of fever as any resident of Keerakadu village with fever for >2 days, with or without headache or myalgia, between April 15 and May 1, 2017. We conducted active surveillance. We reviewed medical records. We collected the line list from nearby health centers. We computed proportions to calculate the attack rate. We collected 11 serum samples and tested for dengue, scrub typhus, hepatitis A and leptospirosis by IgM ELISA method. We did a Widal slide agglutination test. We conducted an environmental survey to identify water sources. We performed a dengue larval survey. We collected 5 water samples: 1 from unprotected well, 1 from overhead tank and 3 from the houses of residents. We tested for fecal coliforms in the district public health laboratory. Results: The population of Keeradu village was 540. We identified 11 cases, for an attack rate of 2% (11 of 540). The hospitalization rate of cases was 81% (9 of 11). Median age was 45 years (range, 23–65). Of 11 samples, 3 were positive for leptospirosis; all were negative for dengue, scrub typhus, hepatitis A, and typhoid. The single water source for the whole village was an open, unprotected well. This well supplied water every day to the community, both for drinking purpose and domestic use. No breeding of dengue larva was observed. All the 5 water samples tested positive for fecal coliforms. Water was not chlorinated regularly. All patients were isolated and treated in the primary health center. Prophylactic antibiotics were given to the whole community. Conclusions: There was a leptospirosis outbreak in Keerakadu village, probably due to contaminated water from unprotected well. There were no cases after May 1, 2017. We recommended that the community chlorinate the water regularly and protect the well. We also recommend continued surveillance and a rodent survey.

Funding: None

Disclosures: None