title: The 2010 outbreak of cholera among workers of a jute mill in Kolkata, West Bengal, India.
abstract: On 10 March 2010, an outbreak of diarrhoeal disease was reported among workers of a jute mill in Kolkata, West Bengal, India. The cluster was investigated to identify the agent(s) and the source of infection and make recommendations. A suspected case of cholera was defined as having >3 loose watery stools in a 24-hour period and searched for case-patients in the workers' colony. The outbreak was described by time, place, and person, and a case-control study was conducted to identify the source of infection. Rectal swabs were collected from the hospitalized case-patients, and the local water-supply system was assessed. In total, 197 case-patients were identified among 5,910 residents of the workers' colony (attack rate 3.33%). Fifteen of 24 stool samples were positive for Vibrio cholerae O1. The outbreak started on 7 March, peaked on 11 March, and ended on 16 March 2010. Compared to 120 controls, 60 cases did not differ in terms of age and socioeconomic status. Drinking-water from the reservoir within the mill premises was associated with an increased risk of illness [odds ratio: 26.7, 95% confidence interval (CI) 11.4-62.6) and accounted for most cases (population attributable risk percentage = 82%, 95% CI 70.8-92.9). An outbreak of cholera occurred among workers of the jute mill due to contamination of the drinking-water reservoir. It occurred within a few days of re-opening of the mill after the workers' strike. Health authorities need to enforce disinfection of drinking-water and regularly test its bacteriological quality, particularly before re-opening of the mill after the strike.
authors.affiliation: Field Epidemiology Training Programme, National Institute of Epidemiology, R-127, Tamil Nadu Housing Board, Ayapakkam, Ambattur, Chennai 600 070, India.
authors.forename: Prakash
authors.initials: P
authors.lastname: Mridha
authors.forename: Asit K
authors.initials: AK
authors.lastname: Biswas
authors.forename: R
authors.initials: R
authors.lastname: Ramakrishnan
authors.forename: Manoj V
authors.initials: MV
authors.lastname: Murhekar
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D002771:Cholera / Q000453:epidemiology*; D003967:Diarrhea / Q000453:epidemiology / Q000382:microbiology; D004196:Disease Outbreaks / Q000706:statistics & numerical data*; D004784:Environmental Monitoring / Q000706:statistics & numerical data*; D062665:Epidemiological Monitoring; D005260:Female; D006801:Humans; D007194:India / Q000453:epidemiology; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D013783:Textile Industry; D041241:Vibrio cholerae O1 / Q000302:isolation & purification; D014871:Water Microbiology; D014881:Water Supply / Q000032:analysis*; D055815:Young Adult