Acute Diarrhea Outbreak in a Condominium-Nonthaburi, Thailand, October – November 2011

Abstract

Background: On November 3^th, 2011, the Bureau of Epidemiology (BOE) received a notification from Infectious Diseases Institute about suspected diarrhea outbreak in Condominium X, located at Bangsimueang Subdistrict, Nonthaburi Province during the worst food in Thailand. BOE and local team conducted a joint investigation in the area, to identify risk factor of diarrhea and to recommend appropriate preventive measures.
Methods: A retrospective cohort study was carried-out to identify suspected water/food items and risk behaviors among all residents in Condominium X during October 20th - November 30th, 2011. A diarrhea case was defined as a resident who developed two of the following symptoms: abdominal pain, loose/watery stool, nausea/vomiting, mucous/bloody stool, fever, dehydration. A rectal swab and tap water samples were collected for bacterial culture. Environmental inspection was done at the condominium and surrounding area. Epi-Info 3.5.3, bivariate analysis and multiple logistic regressions was used.
Results: Of 190 residents surveyed, 71 (37.4%) met a diarrhea case definition. Clostridium perfringens was cultured positive from tap water samples. In crude analysis, risk factors including drinking tap water (Odds Ratio [OR] 7.45, 95% confidence interval [CI]: 4.68-11.86), brushing teeth with tap water (OR 6.24, 95% CI: 2.07- 18.80) In regression model, drinking tap water was a significant risk factor (Adj OR = 85.65, 95% CI: 16.94- 433.10), bottle water for brushing teeth and drinking were protective factor (Adj OR = 0.02, 95% CI: 0.01-0.23).
Conclusions: Contaminated tap water was identified as the significant risk factor however use of bottle water for drinking and brushing teeth was a protective factor.