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.