Aedes aegypti and Dengue Transmission

Abstract

The geographical distribution of the four dengue viruses and their primary vector, Aedes aegypti (A. aegypti), has recently undergone a rapid expansion, establishing endemicity in most of the tropics and subtropics. This places a third of the world’s population at risk of dengue infection, making dengue the most important mosquito-borne viral disease today. Since the 1970’s, the incidence of dengue infections has increased drastically and urban dengue hemorrhagic fever (DHF) has emerged as an urgent global health problem. DHF epidemic activity is currently of particular concern in Southeast Asia, where it is one of the leading causes of childhood mortality. This thesis seeks to understand the mechanisms underlying the re-emergence and emergence of dengue and DHF epidemic activity, respectively, and how they direct available and future preventative measures. The historical and epidemiological record suggests that World War II facilitated the worldwide spread of A. aegypti and the four dengue viruses, establishing hyperendemicity in Southeast Asia. This, along with the particular customs and behaviors of the region, presumably stimulated the emergence of DHF epidemic activity in the 1950’s. Until a safe and effective tetravalent vaccine becomes available, the prevention of dengue rests solely on vector control programs. A more thorough understanding of the transmission cycles between A. aegypti dengue viruses and human hots is needed for the development of more successful vector control programs.