AEDES AEGYPTI AND DENGUE VIRUS INFECTIONS

Aedes-borne diseases (Dengue, Chikungunya, Yellow Fever and Zika) are an emerging problem worldwide, escalating overall risk and burden of disease worldwide. Dengue viruses are members of the family Flaviviridae, genus flavivirus with four anti-genically related but distinct viruses; all are mosquito-borne human pathogens. The four dengue virus serotypes are associated with fever, rash, and the more severe forms, hemorrhagic fever and shock syndrome. Susceptible humans become infected after being bitten by an infected female Aedes mosquito. Viremia in humans begins at the end of a four-six-day incubation period and persists until fever abates. An uninfected Aedes spp. may acquire the virus after feeding on a patient at the vermeil period. Infected mosquitoes carry the virus for their lifespan and pass the virus to its immature
stages (Trans-ovarian transmission) and remain infective for humans, Several factors have combined to produce epidemiological conditions in developing countries in the tropics and subtropics that favor viral transmission by the main mosquito vector, Aedes as the rapid population growth, rural-urban migration, inadequate basic urban infrastructure (eg. the unreliable water supply leading householders to store water in containers close to homes) and the increase in volume of solid waste, such as discarded plastic containers and other abandoned items which provide larval habitats in urban areas. Geographical expansion of the mosquito has been aided by the international commercial trade particularly in used car-tyres which easily accumulate rainwater. Increased air travel and the breakdown of vector control measures have also contributed greatly to the global burden of dengue and DH fevers.