Water quality, availability, and acute gastroenteritis on the Navajo Nation - a pilot case-control study

The Navajo Nation includes approximately 250,000 American Indians living in a remote high desert environment with limited access to public water systems. We conducted a pilot case-control study to assess associations between acute gastroenteritis (AGE) and water availability, use patterns, and quality. Case patients with AGE and non-AGE controls who presented for care to two Indian Health Service hospitals were recruited. Data on demographics and water use practices were collected using a standard questionnaire. Household drinking water was tested for presence of pathogens, coliforms, and residual chlorine. Sixty-one subjects (32 cases and 29 controls) participated in the study. Cases and controls were not significantly different with respect to water sources, quality, or patterns of use. Twenty-one percent (n = 12) of study participants resided in dwellings not connected to a community water system. Eleven percent (n = 7) of subjects reported drinking hauled water from unregulated sources. Coliform bacteria were present in 44% (n = 27) of household water samples, and 68% (n = 40) of samples contained residual chlorine concentrations of <0.2 mg/L. This study highlights issues with water availability, quality, and use patterns within the Navajo Nation, including sub-optimal access to community water systems, and use of water hauled from unregulated sources.