Dengue vector bionomics: why Aedes aegypti is such a good vector

[Extract] Dengue remains the leading arbovirus cause of morbidity in man. There are 3.6 billion people living in areas of dengue risk, with an estimated 390 million infections and 96 million symptomatic cases annually (Beatty et al., 2009, Bhatt et al., 2013). Dengue is vectored by mosquitoes, with several members of the Aedes Stegomyia subgenus serving as vectors. For example, Ae. albopictus is an excellent vector of dengue in the laboratory, and outbreaks in Hawaii (Effler et al., 2005) and Taiwan (Lambrechts et al., 2010) attest to their ability to vector the virus in the field. Differences in the ability for Ae. albopictus to develop disseminated infections of dengue viruses may explain its lower vector competence status relative to Ae. aegypti (Lambrechts et al., 2010). Ae. scutellaris complex members Ae. polynesiensis (Rosen et al., 1954), Ae. katheriensis (Leake, 1984) and Ae. scutellaris (Moore et al., 2007) have been shown to be potential vectors of dengue virus in the laboratory. Ae. polynesienis is suspected of vectoring outbreaks in French Polynesia (Rosen et al., 1954), while Ae. hensilli (Savage et al., 1998) and Ae. scutellaris (Mackerras, 1946) have been linked to dengue transmission in Yap and New Guinea, respectively. However, it is another Aedes (Stegomyia) spp., Ae. aegypti, that is responsible for the bulk of dengue transmission worldwide - and is almost exclusively the vector in large, explosive urban epidemics of dengue (Gubler, 1998; Lambrechts et al., 2010). What is unique about Ae. aegypti that makes it such an effective vector of dengue?\ud \ud Ae. aegypti is arguably the most anthropophilic mosquito (Tabachnick, 1991). Most of its behavior - from immatures residing within man-made, water-holding containers to adult females living inside human domains where they feed almost exclusively on human blood - is tightly linked to man. Its high domesticity truly makes Ae. aegypti the 'cockroach' of mosquitoes, and contributes greatly to its capacity to vector dengue. This chapter will describe Ae. aegypti's close association with man based on the published scientific literature tempered with my own personal experience with the mosquito: I have lived in an unscreened Queenslander house where Ae. aegypti are encountered almost daily, and have directed the dengue control program in north Queensland, Australia for Queensland Health from 1994 to 2010. For an excellent discussion of the evolution of anthropophily in mosquitoes, especially the malaria vector Anopheles gambiae s.s., see Costantini et al. (1999)