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, peakedon 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.

Individual and Household Risk Factors for Symptomatic Cholera Infection: A Systematic Review and Meta-analysis

“…Fifty-six studies evaluated risk of cholera based on source of water, with many identifying a specific culprit [ 17–19 , 21 , 22 , 25–27 , 30 , 32 , 33 , 36 , 37 , 41–43 , 47 , 50 , 59–61 , 63 , 65 , 66 , 68 , 70 , 72–74 , 76 , 78 , 79 , 81–83 , 85–88 , 91 , 92 , 94 , 95 , 97 , 101–108 , 110 , 113 , 116 , 118 ]. Thirty-one studies implemented a multivariable model [ 19 , 26 , 27 , 30 , 32 , 33 , 36 , 37 , 41 , 42 , 60 , 65 , 66 , 68 , 72 , 73 , 78 , 79 , 82 , 83 , 86 , 91 , 92 , 94 , 95 , 101 , 104–106 , 116 , 118 ]. Of these, 20 measured the water source in a way that could be classified as improved (piped househol...…”

“…Thirty-one studies implemented a multivariable model [ 19 , 26 , 27 , 30 , 32 , 33 , 36 , 37 , 41 , 42 , 60 , 65 , 66 , 68 , 72 , 73 , 78 , 79 , 82 , 83 , 86 , 91 , 92 , 94 , 95 , 101 , 104–106 , 116 , 118 ]. Of these, 20 measured the water source in a way that could be classified as improved (piped household, protected well or spring, or collected rainwater) or unimproved, and met criteria for meta-analysis ( Figure 3 ) [ 19 , 27 , 30 , 37 , 41 , 65 , 66 , 72 , 73 , 78 , 82 , 83 , 86 , 91 , 94 , 95 , 101 , 106 , 116 , 118 ]. The SOR for risk of cholera with an unimproved water source was 3.48 (95% CI, 2.18–5.54), with I 2 = 77% ( Q test P < .00001).…”

“…Twenty-four studies assessed risk of cholera with exposure to food from street vendors or outside the home [ 26 , 35 , 41 , 49 , 56 , 57 , 66 , 68 , 70 , 72 , 73 , 78 , 79 , 83–85 , 88 , 91 , 92 , 103 , 109 , 115 , 118 , 119 ]. Seventeen studies implemented multivariable models [ 35 , 41 , 49 , 56 , 66 , 68 , 72 , 73 , 78 , 79 , 83 , 91 , 92 , 109 , 115 , 118 , 119 ], and 12 could be summarized using meta-analysis ( Supplementary Figure 2 ) [ 35 , 41 , 49 , 66 , 72 , 73 , 78 , 79 , 83 , 109 , 115 , 118 ]. The SOR of cholera risk with exposure to street vendor food or food from outside the home was 2.76 (95% CI, 1.62–4.69), with I 2 = 64% ( Q test P = .0008).…”

“…Hand hygiene was assessed in a number of ways, including handwashing before eating [ 20 , 27 , 54 , 56 , 60 , 64 , 79 , 87 , 94 , 97 , 102 , 106 , 109 , 116 ], handwashing after defecation [ 20 , 27 , 35 , 37 , 40 , 65 , 79 , 102 , 106 , 110 ], nonspecific handwashing [ 25 , 39–41 , 49 , 61 , 72 , 73 , 78 , 86 , 88 , 91 ], and presence of soap in the home [ 54 , 64 , 72 , 94 , 97 , 113 , 119 ]. The vast majority of studies measuring handwashing relied on self-report.…”

Individual and household exposures associated with cholera transmission in case–control studies: a systematic review

“…Articles containing multiple studies were recorded as separate studies if the study populations were different and the data could be separated in the articles. Significant water-related exposures related to transmission in the domestic domain included drinking from home storage containers [40,88], putting hands in household water containers [73], or not covering stored water [60]. In 53% of studies that assessed water-related exposures, there was at least one significant water-related exposure where the transmission domain could not be determined.…”