A point source outbreak of acute gastroenteritis among school students in Kerala, India.

An outbreak investigation was initiated following an outbreak of acute gastroenteritis among schoolchildren in Kottarakara. Steps included active search for cases at schools, describing the outbreak in terms of person, place, and time, generating hypothesis based on the findings from descriptive study, environmental observations, and testing the hypothesis using a case-control design. The final line list consisted of 871 children from different schools who attended a Republic Day parade. Having consumed the lemon juice near railway station (odds ratio [OR] 29.14; 95% confidence interval CI 9.06-93.67) during Republic day parade was associated with the outbreak. The time frame of the disease occurrence, laboratory results, and the results of the analytical study indicated the point source of acute gastroenteritis outbreak as the contaminated water used for lemon juice distributed during the parade. The findings warrant effective food and water safety surveillance, especially during mass gatherings.