Cholera outbreak associated with contaminated water sources in paddy fields, Mandla District, Madhya Pradesh, India

BACKGROUND: Mandla District in Madhya Pradesh, India, reported a suspected cholera outbreak from Ghughri subdistrict on August 18, 2016. OBJECTIVE: We investigated to determine risk factors and recommend control and prevention measures. METHODS: We defined a case as >3 loose stools in 24 h in a Ghughri resident between July 20 and August 19, 2016. We identified cases by passive surveillance in health facilities and by a house-to-house survey in 28 highly affected villages. We conducted a 1:2 unmatched case-control study, collected stool samples for culture, and tested water sources for fecal contamination. RESULTS: We identified 628 cases (61% female) from 96 villages; the median age was 27 years (range: 1 month-76 years). Illnesses began 7 days after rainfall with 259 (41%) hospitalizations and 14 (2%) deaths in people from remote villages who died before reaching a health facility; 12 (86%) worked in paddy fields. Illness was associated with drinking well water within paddy fields (odds ratio OR = 4.0, 95% confidence interval CI = 1.4-8.0) and not washing hands with soap after defecation (OR = 6.1, CI = 1.7-21). Of 34 stool cultures, 11 (34%) tested positive for Vibrio cholerae O1 Ogawa. We observed open defecation in affected villages around paddy fields. Of 16 tested water sources in paddy fields, eight (50%) were protected, but 100% had fecal contamination. CONCLUSION: We recommended education regarding pit latrine sanitation and safe water, especially in paddy fields, provision of oral rehydration solution in remote villages, and chlorine tablets for point-of-use treatment of drinking water.