A community based Acute Gastroenteritis outbreak investigation in Senthaneerpuram, a semi-urban area,Tiruchirappalli Corporation, Tamil Nadu-India, 2016

Abstract

Background: Diarrhea and food borne diseases account for half of the outbreaks reported in India but many are not fully investigated. On 11thJune 2016, Senthaneerpuram, located within Tiruchirappalli Corporation reported an increase in acute gastroenteritis cases. This study was aimed to investigate and identify the agent, source and to propose recommendations. Methods & Materials: A case of acute gastroenteritis is defined as persons with ≥3 watery stools and vomiting within 24 hours among the residents of Senthaneerpuram during 11-17 June 2016. Cases were searched in door-to-door. The outbreak was described by time, place and person. A case control study was carried out in 134 cases with 134 controls keeping an assumption of expected non exposure among the controls 40% with odds ratio of 2. The odds ratio (OR) with 95% confidence intervals (CI) was computed. The controls were persons without acute gastroenteritis residing in the same neighborhood as the cases. We collected 6 stool samples tested for Vibrio cholerae, salmonella and shigella by culture. The environment was assessed and 5 water specimens were collected. Results: The study was carried out by identifying 169 suspected cases (attack rate: 2.8% (169/5966), highest in 41-59 years age group 7%(62/894) and no deaths. Prominent symptoms were fever (78%), abdominal pain (82%) and vomiting (30%). The outbreak started on June 9 and lasted till June 30 with multiple peaks. Clustering of suspected cases was more in Gandhi street (Attack rate: 21%(39/190) followed by Paris street 17%(49/284). Among 134 cases and controls, using public street piped water for drinking (OR: 7.3, 95%CI = 3.5-15.3) was the risk factor. Rectal specimens were negative for Vibrio cholerae, salmonella and shigella. There was also leakage in the public water pipe line and water specimens showed coliforms. Conclusion: The investigation suggested that this acute gastroenteritis outbreak is due to the consumption of contaminated water from the damaged public water pipeline. The public water pipeline was repaired, chlorinated and residences were educated.