Cholera Outbreak Investigation in Nadiad City, Kheda District, Gujarat, India, June–July 2021
Authors: Kokare Vikas, Gupta Vikas Kumar, Kurup Karishma Krishna, Solanki Jayesh, Gupta Rajul Kumar, Kaur Ismeet, Dzeyie Kevisetuo Anthony, Nyugen Tran Minh Nhu
Background: On June 30, 2021, the urban primary health centre (UPHC) of Nadiad City reported a cluster of suspected cholera cases. We investigated to describe the epidemiology, identify contamination sources, and provide evidence-based recommendations.
Methods: We reviewed reported cholera cases in the last 10 years in Nadiad City to confirm the outbreak. A suspect case was defined as 3 loose stools within 24 hours in a resident of UPHC, Nadiad City, between June 10–July 31, 2021. We identified cases by house-search and record review of UPHC and interviewed them using a semi-structured questionnaire for demographic, treatment history, and drinking water supply. We collected stool samples for bacterial culture, water samples for residual chlorine, and inspected the water pipelines.
Results: Nadiad City had not reported a cholera case in the last 10 years. We identified 121 cases (56% female) including 1 death (CFR:0.6%); 109 (90%) received treatment in a health care facility, and 85 (70%) were hospitalized. The median age was 24 years (range: 6 months–70 years). The outbreak began on June 15, peaked on July 1, with the last case reported on July 18, 2021. Cases were concentrated around 3 nearby localities. Among the cases, 120 (95%) had pipeline-supplied water as the main drinking water source, 111 (92%) did not use any water purification methods, and 79 (65%) reported foul smell/discolored water 1 week before the outbreak. Of the 21 individual stool samples, 7 tested positive for Vibrio cholerae and 160/1301 (13%) water samples did not show residual chlorine. We observed damaged pipelines at 4 locations in the outbreak area.
Conclusions: We report a laboratory-confirmed cholera outbreak likely due to contaminated pipeline-supplied water. We recommended the public health engineering department temporarily stop the water supply, repair damaged pipelines, and do chlorination. Medical officers were briefed for early suspicion and laboratory testing of suspected cholera cases.