Intestinal parasitic diseases in Riyadh, Saudi Arabia: prevalence, sociodemographic and environmental associates.

Our objectives were to assess the prevalence of intestinal parasitic infections in Riyadh and to determine associated sociodemographic and environmental factors. The study was conducted through a household survey. Three health centres were chosen from each of the five Riyadh urban regions and 15 from rural areas. Based on the average family size, a random sample of households were chosen. All household members were asked to participate in the study. Data were collected using a pre-designed questionnaire eliciting data on sociodemographic and environmental factors. A stool specimen of each individual was examined microscopically for the presence of trophozoites and cysts. Six thousand and twelve participants with a mean age of 23.3 +/- 17.4 (median 19 years, 48.6% males) were studied and 32.2% were infected. The infection rate was high in urban areas (33.3%), among children < 12 years (34.4%), non-Saudis (42.2%), single persons (34.9%), illiterate individuals (33.8%), those who obtained drinking water from tankers (36.1%) and those who disposed of sewage in open channels (47.1%). Stratified analysis showed that for Saudis <12 years parasitic infections were significantly higher among tanker users (39.5%) and septic tank users (36.8%). For Saudis> or =12 years low education, water storage and open sewage disposal were statistically associated with parasitic infections (P < 0.05). Among expatriates, infections were high among males (47.6%), urban residents (48.3%), single persons (46.9%), tanker users (39.5%) and septic tank users (78.6%). Multivariate logistic regression analysis showed that age < 12 years, non-Saudi nationalities, educational level below secondary school, tanker as source of water and open sewage disposal were independently associated with high intestinal parasitic infection.