Hyperendemicity of diarrhea in a valley area, Asir Region, southwestern Saudi Arabia.

: A random sample of 781 subjects living around a valley in Shebaa area, southwestern Saudi Arabia, and 1284 subjects from the rest of Shebaa, along with a sample of 1095 from a nearby urban community in Abha city have been studied following a notification of a suggestive increase of diarrhea in the valley. This was to determine whether the prevalence of diarrhea was high in the valley and to formulate hypotheses about possible implicated factors. The family head was interviewed about episodes of diarrhea among family members during the 2-week period preceding the interview, about source of drinking water, and about some demographic variables. Observations were made and data were collected on presence and frequency of flies in the house, methods of excreta and refuse disposal, valley and wells water, and the nearby agricultural farms. The 2-week diarrhea episode rate per subject was significantly (p<0.0001) highest in the valley (0.20), was 0.09 in the rest of Shebaa, and was lowest in the urban community area. (0.05). The rate decreased by age (p<0.001) and increased by frequency of flies in the house (p<0.0001), particularly in the valley. Drinking only from the desalinated water was associated with diarrhea episode rate of 0.12 as compared to 0.05 for drinking only from bottled water or from any other combination of sources (p<0.01). The valley and wells water was grossly polluted and was regularly used for irrigating and washing fresh fruits and vegetables from nearby farms. Hypotheses for the factors possibly contributing to this hyperendemicity of diarrhea in the valley include inadequate excreta and refuse disposal, contamination of the valley and wells water, contamination of the desalinated water during transportation or storage and abundance of flies.