Cholera Outbreak in Serampore Municipality, Hooghly, West Bengal, India, April-May 2022

Water or foodborne
Environmental Health (Including Water & Sanitation)

Background: In India, between 2011 and 2020, 565 reported cholera outbreaks led to 45,759 cases and 263 deaths. On 18 April 2022, a sub-divisional hospital reported four confirmed cholera cases from Serampore municipality area of West Bengal, India. We investigated to describe the epidemiology and recommend control and preventive measures.

Methods: We defined a suspect case as ≥3 loose stools within 24-hours in a resident of Serampore municipality from 1 April–31 May 2022, and a confirmed case as culture positive result. We identified cases by house-to-house search and review of hospital records at the sub-divisional hospital. We interviewed cases for information on demography, clinical profile and source of drinking water using a semi-structured questionnaire. We assessed water supply system and sewage lines in Serampore municipality. Stool samples were tested for Vibrio cholerae by culture and water samples from the affected municipality wards for fecal contamination by H2S test. We analyzed data using Epi Info Version 7.2.

Results: We identified 406 cases (63% female) including three deaths (case fatality: 0.7%) with median age 33 years (range: 12–50 years); attack rate was 2.3 per 1,000 population. Of the cases, 337 (83%) used municipal water for drinking and none used any water purification method. We observed that water quality surveillance was not done in the last six months, identified multiple leakage points in water pipelines within one meter of sewage lines. Of 10 stool samples tested, six showed Vibrio cholerae 01 El Tor serotype Ogawa and 3/6 (50%) drinking water samples showed fecal contamination.

Conclusions: We report a confirmed outbreak of Vibrio cholerae 01 El Tor serotype Ogawa likely due to drinking contaminated municipal supplied water. We recommended immediate management of cases with oral rehydration solution, repair of leakage pipes, drink boiled water and establishing long-term water surveillance with pipeline maintenance to prevent future cholera outbreaks.