Outbreak of Gastroenteritis in Tibetan Transit School, Dharamshala, Himachal Pradesh, India, 2006

BACKGROUND: On 28(th) June, 2006, 55 cases of the gastroenteritis were reported among the hostellers of the Tibetan Transit School, Dharamshala. We investigated the outbreak to identify the source, propose control and preventive measures. MATERIALS AND METHODS: We defined a case of the gastroenteritis as the occurrence of more than three smelly loose motions between 28(th) June to 2(nd) July, 2006 among some sections of the resident hostellers. We determined age and sex specific attack rate. We hypothesized it as a food borne beef meat outbreak. We conducted the case control study and collected the information about the food items consumed inside and outside the hostel at dinner using the standardized questionnaire. We calculated floor wise incidences of four hostels, odds ratios and attributable fractions. We interviewed food handlers. We lifted the seven rectal stool, four water and three samples from floor, kitchen and meat chopper room for culture and sensitivity. RESULTS: 116 cases patients of 802 hostellers met the case definition. The maximum attack rate (16%) was in the youngest group (15-20yrs) and nil in staff and 31-40 years age group with 5 overall attack rate as 14%. Sex specific attack rate was more (18%) in females. The floor wise incidences of the case patients were the highest in 2nd and 3rd floors, occupied by the youngest group. The median age was 20 yrs (Range 17-40 yrs). The most common symptoms were watery diarrhea (71/116, 61%) and bloody diarrhea-(45/116, 39%); abdominal pains-(87/116, 75%). Of the six food/water items examined, the food specific attack rate was highly statistically significant in the beef meat eaters (82% with PAF 71%), and Odds Ratio 19.19 (95% C.I. as 9.3-140). The food handlers & their cooking conditions in the kitchen were unhygienic. The food was not available for testing. Escherichia coli were detected in the samples from rectal stools, kitchen and meat chopper room. No fatality was reported. CONCLUSION/RECOMMENDATION: The beef meat purchased from outside was implicated for the explosive common source outbreak. The school authorities were counseled for hygienic food handling.