Malaria and dengue vector biology and control in Southeast Asia

Abstract

This chapter reviews the situation of vector biology and control of both malaria and dengue in the Southeast-Asian region as part of the World Health Organization (WHO/TDR) working-group meeting on strategic planning to bridge laboratory and field research in disease vector control. Many research studies on malaria were related to the survey of malaria vectors and parasites and their spatial and temporal distribution in each country. A few studies demonstrated application of molecular tools to identify sibling species in the vector complexes as well as the genetic structure and gene flow among these complex species. Despite insecticide resistance having been detected in many vector species, insecticide-impregnated bednets are still reported as a cost-effective and efficient way for malaria control. Social-science and socio-economic studies indicate that the level of education and poverty is related to the risk of malaria infection and also emphasize the importance of education as part of successful control programmes. The majority of research on dengue vectors in Southeast Asia involves surveillance for species composition, relative abundance and seasonal distribution of both immature and adult stages. Identification of key breeding containers and patterns of landing/biting of adults are routinely investigated in the study areas. Some aspects of vector ecology and vector biology related to the symbionts of the mosquitoes have been reported. Several studies have pointed out the importance of human transportation as a means for spreading dengue. Recent studies also demonstrated that the disease spread from the larger cities, which serve as the viral reservoirs, to smaller communities in a radial manner. Several socio-economic studies in different countries indicate variations in knowledge and practice related to dengue. Dengue control programmes in Southeast Asia have recently shifted from application of insecticides to integrated vector control strategies using biological control agents, pyrethroid-based insecticides, source reduction and environmental management. However, most of the present vector control measures are not sustainable due to several factors related to both community participation and persistence of public-health vector control programmes. Genetic control using modern molecular technologies may offer novel solutions for future control of vector-borne diseases