A cross-sectional study of enteric disease risks associated with water quality and sanitation in Hyderabad City

This paper describes a cross-sectional, questionnaire-based study to estimate enteric disease risks from drinking water and poor sanitary conditions in Hyderabad City, India. Community incidence rates of enteric diseases potentially transmitted through water (acute gastrointestinal infections, typhoid, hepatitis A) obtained from questionnaire administration were found to be approximately 200-fold greater than estimates based on hospital incidence data. Community incidence rates were therefore used for comparison with a range of socio-economic and drinking water system parameters. The incidence of these diseases was found to be significantly higher in areas where sewage overflows were frequent and where sewage could accumulate around the home, where utensils were cleaned on the street, where water distribution pipelines leaked and where no residual chlorine was maintained. Surprisingly, socio-economic factors such as education and income were not strongly associated with waterborne diseases.

Regression modelling also supported an association between health outcome and the following independent variables: rate of sewage overflow, % of cast iron pipe (as a measure of less leakage potential) and % samples without residual chlorine. The strength of the relationships suggests that improvement in sewage collection systems and water disinfection, and repair of water distribution system leakage should result in significant reduction in enteric diseases. This study provides a simple epidemiological approach to identify preliminary linkages between water quality and disease that can be used to affect policy decisions.