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Integrated interventions for dengue and diarrhea in rural schools in two municipalities of Colombia


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Tipo de publicación

Científica

Tipología

Investigación y estudios

Medio de publicación

Eventos: Congreso

Resumen

 The relationship between diarrheal disease and dengue fever has been poorly studied, although there is a potential causal link between the two. Poor water storage conditions may result in contaminated water and provide breeding sites for dengue mosquitoes. The WHO estimates that about 1.8 million people die every year from diarrheal diseases and that 88% is attributed to unsafe water supply, inadequate sanitation and hygiene. Additional improvement of drinking-water quality, such as point-of-use disinfection, would lead to a reduction of diarrhea episodes of 45% and the simple act of washing hands at critical times can reduce the number of diarrheal cases by up to 35%. Dengue is the most common mosquito-borne viral disease of humans that in recent years has become a major international public health concern. Globally, 2.5 billion people live in risk areas. The geographical spread of both the mosquito vectors and the viruses has led to the global resurgence of epidemic dengue fever and emergence of dengue hemorrhagic fever in the past 25 years with the development of hyperendemicity in many urban centers of the tropics.


The presence of Aedes aegypti in rural areas, specifically in schools, would endanger the health of students. Rural schools as almost all rural areas in Colombia do not have an adequate solid waste disposal system; some of this rubbish can serve as mosquito breeding sites during the rainy season. Tanks for water storage are often not closed or have lids in bad conditions offering attractive breeding places. Further, the drinking water in rural schools is often of poor quality because of contaminated water sources, lack of treatment and poor storage conditions.


The main objective of this project is to assess the impact of integrated interventions to reduce diarrheal disease and dengue vector infestation in 34 rural schools in the municipalities of La Mesa and Anapoima, Cundinamarca department, Colombia. The secondary outcomes are reduction in the number of school absence episodes, improving drinking water quality, advancing knowledge and practices about both diseases in teachers and pupils.


La Mesa and Anapoima are located at 1200 and 700 m.a.s.l. altitude and have an annual average temperature of 22°C and 25°C, respectively. The average annual precipitation in both municipalities is from 1.000 to 2.000mm. The rural population in La Mesa is 12.922 and in Anapoima 7.922. Each municipality has 17 schools with a total of 873 pupils aged 5 to 16 years in grades 0 to 5.


This is a 2x2 factorial cluster randomized controlled trial. There are two sets of interventions, dengue and diarrhea. An initial stratification was made by municipality followed by random assignment of schools to one of four arms: dengue, diarrhea, dengue/diarrhea and control. Each school receives one, both, or none of the interventions. Control schools will receive the interventions at the end of the project. Interventions for diarrhea are: 1) Improvement in drinking water quality through the provision of ceramic filters 2) Improvement in hygiene through the provision of liquid soap for hand washing and cleaning kit for restrooms and 3) Prevention of water re-contamination through washing and covering of drinking water tanks (those tanks that cannot be easily covered will be provided with a net to prevent contamination from animals and plants). Interventions for dengue are: 1) Covering tanks (with plastic covers or nets) to prevent mosquito infestation 2) Application of the insect growth regulator pyriproxyfen to tanks (when covering is not possible) 3) Solid waste collection and 4) Controlling adult mosquitoes by insecticide impregnated curtains. These interventions are supported by educational components in the form of teacher’s guides, posters, leaflets designed to sensitize pupils and teachers about the prevention and control of the two diseases. Baseline data were collected in 2011 and interventions implemented during the first school semester of 2012 (February-June). The interventions will be continuously monitored for two years. The following will be recorded: daily absences of students and reasons for absences; mosquito infestation (immature and adult indices), water quality (bacteriological and physico-chemical parameters), knowledge, attitudes and practices (KAP) of pupils and teachers.


The baseline data showed that drinking water contained Escherichia coli in 76.5 % of the schools in Anapoima and in 94 % of the schools in La Mesa. Adult Ae. aegypti mosquitoes were present in 18 schools (53%) during the wet season and in 14 schools (41%) during the dry season. Ae. aegypti immatures were collected in 7 schools (21%) during the wet season and in 6 schools (18%) during the dry season, corresponding to Breteau indices of 41 and 18, respectively. The most common Ae. aegypti breeding sites were storage containers for drinking water and other containers (e.g. jars, bottles and tank lids).

Autores

MI Matiz, JF Jaramillo, VA Olano, D Sarmiento1, SL Vargas, A Lenhart, N Alexander, R Seidu, TA Stenström, H Overgaard

Fecha de publicación 21 de octubre de 2012
Fecha de aceptación 18 de marzo de 2012

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