This study is a community assessment, examining people's water practices and control practices in households against Aedes aegypti, the vector of dengue virus, to provide information for improving dengue control promotion. The study took place in Khon Kaen province, where two locations were selected, the city of Khon Kaen Municipality representing urban areas and Khok Pho Chai district representing rural areas. The research methods used were a combination of qualitative methods and a questionnaire survey to explore the similarities and differences of people's perceptions and larval control practices between rural and urban areas. The control campaigns use health education and distribution of control supplies as a main strategy. As the main breeding sites in Khon Kaen are water storage containers in households, control activities against mosquito larvae in containers such as using temephos, fish, lids covering containers, and weekly emptying and cleaning of containers, are promoted.
The study covered 966 households (rural 480, urban 486) and 5822 containers were inspected (rural 3893 urban 1928). The mean number of containers per household was four in urban areas and eight in rural area. There were seven major container types and each type was used with variable frequencies and stored water used for different activities (drinking, washing, bathing, and flushing toilets). Each of these seven container types was examined for mosquito larvae and water practices and larval control actions were ascertained. The containers most frequently infested with larvae were rectangular cement containers storing water for bathing (rural 37.2% urban 35%) and flushing toilets (rural 35.7%, urban 34.3%), and small dragon jars (rural 21.6%) urban 57.1%)). All of these containers are used for storing non-potable water. The mosquito indices greatly exceed the safe indices for dengue transmission risk defined by the Ministry of Public Health: the Breteau Index was 201 in rural areas and 113 in urban areas, and Container Index was 25 in rural areas and 28.5 in urban areas.
Larval control in containers is complicated especially the use of temephos and control practices are often incorrectly implemented. Problems in the use of temephos are - incorrect amounts being applied, and method of application and frequency of addition being incorrect. Temephos was used in more rural households (37%) than urban households (19%, P < 0.001). Overall, the percentages of containers treated with temephos containing larvae in rural areas was twice as high as in urban areas (rural: 9%, urban: 4.7%). Temephos was effective for larval control in dragon jars in urban areas (OR=0.46 [0.23, 0.94]) as temephos was distributed in packages designed for dragon jars, which ensured the correct amount was used. Lids were used for protecting water especially drinking water (rural 97%, urban 98%) but some lids were broken (rural 6%, urban 12%) or ill fitting (rural 11%, urban 22%). Lids were effective for larval control only if lids correctly covered containers (dragon jar OR= 0.25 [0.13, 0.48], large cement jars OR= 0.12 [0.07, 0.19]). Using larvivorous fish was very effective as less than 1% of containers with fish contained larvae. However, fish were kept in only a few water containers for larval control (rural 7%., urban 4%), while fish were often kept for recreation in water plant containers (74%). Weekly emptying and cleaning of containers was effective for larval control but not in large containers such as large cement jars, which were normally cleaned yearly. Only 13.9%) of containers in rural areas and 40% of containers in urban areas were emptied weekly.
The dengue control program in Thailand has employed health education based on the Health Belief Model (HBM). This model emphasizes the psychological aspects of behaviour change and hence focuses attention on individual rather than community issues. Findings from this study indicate that health education messages can raise awareness during an outbreak but do not ensure sustained change in the long term. Several barriers are identified, including insufficient control agents, lack of knowledge of control methods, and incompatibility of control practices with people's existing beliefs. The barriers prevail over the benefits of recommended larval control practices. This study shows that larval control effectiveness is affected by water practices, so in developing health education messages, consideration should go beyond the HBM and focus on control methods that are compatible with household water practices as well as the differences in socio-cultural factors affecting people's water practices and control practices in rural and urban areas. Finally, it is suggested that the notion of community participation is only superficially applied in this program, and that a deeper commitment to community development is required if genuine community ownership is to be achieved.