Dengue and diarrheal disease risk factors in rural and suburban villages in Thailand and Laos


Diarrheal diseases and dengue fever are major global health problems. Household drinking water (DW) storage can be a determinant for both diseases if water is fecally contaminated and the storage containers provide breeding sites for dengue mosquitoes. The aim of this project is to assess health risks associated with household water storage practices by identifying relationships between household water management, contaminated DW, and mosquito production. In 2011 we collected entomological, bacteriological, and socioeconomic data from one rural and one suburban village in northeastern Thailand and southern Laos, respectively. In rural Thailand, almost 100% of the study population use rainwater as DW. In rural Laos 83% use unprotected wells in the dry season and 92% use rainwater in the rainy season. In the suburban settings DW sources are rainwater and bottled water. There was an average of 2.5 DW containers per household. Only 6% of households in rural Thailand and 43% in rural Laos treat their DW. These figures were higher for the suburban areas (Thailand: 65%; Laos: 84%). Water holding containers were found in >93% of the households, of which ~19% were positive for Aedes aegypti immatures. The most productive containers were cement tanks in both countries, representing 15-17% of all encountered pupae. The Breteau index (BI) was higher in Thailand than in Laos (140 vs 845, p<0.01). In Thailand the BI was higher in the rural area than in the suburban area (147 vs 134, p<0.01), whereas in Laos the opposite was observed (112 vs 56; p<0.01). In Thailand almost 10% of the Aedes positive containers were used for drinking, whereas in Laos as many as 25% were used for drinking. Of the Aedes infested DW containers 26% in Thailand and 51% in Laos were also contaminated with Escherichia coli. The results suggest an intricate relationship between water contamination and mosquito production in household water storage containers. This relationship and the role of domestic water management practices as risk factors for both dengue and diarrheal disease will be discussed.

The American Journal of Tropical Medicine and Hygiene Volume 87, Issue 5_Suppl_1, Nov 2012, p. 237
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