Investigation of a Community Outbreak of Diarrhea Associated with Drinking Water in

Objectives: To identify the etiology and source after recognition of diarrhea outbreak is associated with drinking water in suburb of Chengdu. Methods: Both unmatched case control and retrospec-tive cohort study were conducted. 131 targets including 56 suspected patients were recruited for case control study, while 463 residents were selected for cohort study. Stool, water and environ-mental samples were collected for laboratory testing. Results: The proportion of case exposed to well water was 86 % in case group compared with 51 % in the controls during the epidemic period (OR = 6.14, P < 0.01). Exposing to well water (RR = 3.14, P < 0.01) and the distance between well and river (RR = 2.59, P < 0.01) were at higher risk for diarrheal illness. Nucleic acid of Enteropa-thogenic E. coli and Enterotoxigenic E. coli was positive in stool and river samples. Conclusions: This outbreak of diarrhea might be caused by several mixed opportunistic pathogens in well wa-ter contaminated from the river water