Five Pond-centred Outbreaks of Cholera in Villages of West Bengal, India: Evidence for Focused Interventions.

In rural West Bengal, outbreaks of cholera are often centred around ponds that is a feature of the environment. Five investigations of laboratory-confirmed, pond-centred outbreaks of cholera were reviewed. Case-control odds ratios were approximated with relative risks (RRs) as the incidence was low. The environment was investigated to understand how the pond(s) could have become contaminated and could have infected villagers. The five outbreaks of cholera in 2004-2008 led to 277 cases and three deaths (median attack rate: 51/1,000 people; case fatality: 1.1%; median age of case-patients: 22 years; median duration: 13 days, range: 6-15 days). Factors significantly (p<0.05) associated with cholera in the case-control (n=4) and cohort investigations (n=1) included washing utensils in ponds (4 outbreaks of cholera, RR range: 6-12), bathing (3 outbreaks of cholera, RR range: 3.5-9.3), and exposure to pond water, including drinking (2 outbreaks of cholera, RR range: 2.1-3.2), mouth washing (1 outbreak of cholera, RR: 4.8), and cooking (1 outbreak of cholera, RR: 3.0). Initial case-patients contaminated ponds through washing soiled clothes (n=4) or defaecation (n=1). Ubiquitous ponds used for many purposes transmit cholera in West Bengal. Focused health education, hygiene, and sanitation must protect villagers, particularly following the occurrence of an index case in a village that has ponds.

Prevalence and pattern of substance use among the higher secondary school students of Imphal, Manipur, India.

Background. Substance use often begins in adolescence. We did a study to describe substance use and its associated factors among adolescent students in Imphal. Methods. We defined substance use as the use of licit and illicit substance other than when medically indicated. Using a WHO self-administered questionnaire, we collected information about substance use from 61 randomly selected students of 17 government/private higher secondary schools. We calculated the prevalence of substance use according to selected characteristics. Results. We surveyed 1020 students, 551 of whomreported prior substance use (prevalence of ever use: 54%, 95% confidence interval [CI] 42%–67%). Prevalence of recent and current user was 35% (95% CI 28%–43%) and 22% (95% CI 17%–28%), respectively. Among ever users, tobacco (46%) was used most commonly, followed by alcohol (29%), cannabis (14%) and opiates (12%). On multivariate analysis, substance use was significantly higher among boys (adjusted odds ratio [AOR] 2.6, 95% CI [2.0– 3.4]), whose father (AOR 2.0, 95% CI 1.6–2.7) or sibling (AOR 2.1, 95% CI 1.5–3.0) used substance. It was significantly lower among children of Hindu/Jain religion (AOR 0.5, 95% CI 0.4–0.7). Conclusion. Prevalence of tobacco and alcohol use was high among students. Familial use of substances was associated with the behaviour of adolescents. Friends were the key proximal determinant. We recommend introducing a substance use prevention policy in schools to educate students about various adverse effects and to impart refusal skills.

Strategies to improve the performance of female health workers in West Bengal: A cross-sectional survey.

Background. Female health workers in India face an increasing workload that affects their performance. We did a study in 2 districts of West Bengal, India, to quantify their workload and identify determinants of good performance. Methods. We randomly sampled female health workers from the health department’s list. First, we quantified the time allocated to tasks through observations of work sessions. Second, we estimated the prevalence ratio (PR) of aboveaverage performance for three indicators (DPT-booster coverage, antenatal check-up coverage and family planning performance) according to selected potential determinants. Results. Female health workers spent 26% of their time in documentation. We recruited 42 female health workers (average population covered: 6495). Larger floor space (PR 2.5; 95% CI 1.2–5.3), use of simplified documentation procedures (PR 2.5; 95% CI 1.2–5.2) and monthly supervision (PR 3.0; 95% CI 1.1–8.5) were associated with above-average DPT-booster coverage. Availability of a private space was associated with above-average coverage in antenatal check-up (PR 1.9; 95% CI 1.0–3.5) and family planning (PR 2.5; 95% CI 1.2–5.2). Workers who used existing resources to cope with multi-tasking performed better. Conclusion. Female health workers spent excessive time in documentation which left less time for service delivery. Infrastructure, planning and supervision affected performance and these areas must be strengthened to improve primary healthcare services.

An Outbreak of Cholera Associated with an Unprotected Well in Parbatia, Orissa, Eastern India.

In November 2003, an outbreak (41 cases; attack rate–4.3%; no deaths) of severe diarrhoea was reported from a village in Orissa, eastern India. Thirteen of these cases were hospitalized. A matched case-control study was conducted to identify the possible exposure variables. Since all wells were heavily chlorinated immediately after the outbreak, water samples were not tested. The cases were managed symptomatically. Descriptive epidemiology suggested clustering of cases around one public well. Vibrio cholerae El Tor O1, serotype Ogawa was isolated from four of six rectal swabs. The water from the public well was associated with the outbreak (matched odds ratio: 12; 95% confidence interval 1.2-44.1). On the basis of these conclusions, access to the well was barred immediately, and it was protected. This investigation highlighted the broader use of field epidemiology methods to implement public-health actions guided by epidemiologic data to control a cholera epidemic.

Investigating outbreaks: Practical guidance in the Indian scenario.

The new International Health Regulations, 2005, which came into force in 2007, establish a national focal point in each country to manage public health emergencies of international concern, including outbreaks. Investigating outbreaks is a challenging task. Often, pressure from decision-makers to hasten investigation may preclude proper evidence-based conclusions. Furthermore, the task of outbreak investigation is given to senior staff, who have limited time for field activities. The classical 10-step approach includes 4 main stages of (i) confirmation of the presence of the outbreak and of diagnosis using laboratory tests, (ii) generation of hypotheses regarding causation using descriptive epidemiology findings, (iii) hypothesis-testing using analytical epidemiology techniques, and (iv) institution of prevention measures. Peer-review at all stages of the investigation and reporting is the keystone of the quality assurance process. It is important to build capacity for outbreak investigation. Two Field Epidemiology Training Programmes in India are trying to do this. In these programmes, epidemiologists-intraining take a lead in investigating outbreaks, while learning the ropes, with full technical support from the faculty. This training should spawn a culture of generating and using evidence for decision-making in the context of public health, and help strengthen health systems even beyond the domain of outbreaks.

An outbreak of hepatitis E tracked to a spring in the foothills of the Himalayas, India, 2005.

In July 2005, cases of hepatitis were reported from three villages in Nainital district, Uttarakhand, India. We investigated this cluster to identify the source and propose recommendations. A door-to-door search for cases of acute hepatitis was carried out in the three villages. We described the outbreak by time, place and person and conducted a cohort study to identify the source of infection. In addition, sera from cases were tested. We identified 205 cases among 1238 persons (attack rate: 16%, no deaths) between May and September 2005. Of the 23 sera tested, 21 were positive for IgM antibodies against hepatitis E virus. The attack rate was highest among 15–44 years old (19%). Cases began on May 3, 2005, peaked in July and decreased rapidly. The incidence was highest (23%) in one of the villages predominantly using water from an unprotected spring, which was distributed after stone bed filtration alone. In this village, the attack rate increased from 9% among those not using the spring, to 13.8% among those partly using it (RR [95% CI] 1.6 [0.8-3.4]), and to 29% among those exclusively using it (RR [95% CI] 3.4 [2.0-6.0]). Untreated drinking water from an unprotected spring may have been the source of this outbreak in a rural area. Sources of water supply must be protected and treated, including with chlorination. Reporting and investigation of smaller outbreaks in rural areas should be improved.

Cholera outbreak secondary to contaminated pipe water in an urban area, West Bengal, India, 2006.

Outbreaks of cholera are common in West Bengal. In April 2006, Garulia municipality reported a cluster of diarrhea cases. We investigated this cluster to identify the etiological agent, source of transmission and propose control measures. We defined a case of diarrhea as occurrence of >3 loose/watery stools a day among the residents of Garulia since April 2006. We searched for cases of diarrhea in health care facilities and health camp. We conducted a gender- and age-matched case–control study to identify risk factors. We inspected the sanitation and water supply system. We collected rectal swabs from diarrhea patients and water specimens from the affected areas for laboratory investigation. Two hundred and ninetyeight cases of diarrhea were reported to various health care facilities (attack rate: 3.5/1000, no deaths). The attack rate was highest among children (6.4/1000). Vibrio cholerae El Tor O1 Inaba was isolated from two of 7 rectal swabs. The outbreak started on 10 April 2006, peaked on 26 April and lasted till 6 May. Cases clustered in an area distal to leaking water pipelines. Drinking municipal water exclusively was significantly associated with the illness (OR 13, 95% CI=6.5–27). Eight of the 12 water specimens from the affected area had fecal contamination and poor chlorine content. This outbreak was due to a contaminated municipal piped water supply and V. cholera 01 Inaba was possibly the causative organism.