Epidemiology D engue fever has a wide distribution, coinciding with that of the Aedes aegypti mosquito, its principal vector, occurring in the tropics and warm zones of temperate regions. It is more prevalent in Asia, Africa and Americas, although one of the earliest dengue epidemics had been described in Massachusetts, northern United States. It is transmitted by a mosquito, the Aedes aegypti , which is abundant in and around human habitations. Other species have been related to dengue transmission, including Aedes albopictus , Aedes scutellaris , Aedes polynesiensis . Humans become infected after being bitten by the female Aedes mosquito.
Viremia begins after six days and persists until fever abates.
If an unaffected Aedes mosquito bites a human in the viremia period, it acquires the virus and the dengue fever cycle is maintained. Once infected, mosquitoes carry the virus for their lifespan. Aedes aegypti mosquitoes are distributed in tropical and subtropical areas, from latitudes 45 north to 35 south. In the Americas, because of health programs during the 1950's and 1960's to eradicate yellow fever, which has the same vector, its distribution had been restricted, but the mosquitoes reinfested all of their former habitats since 1970. They are daytime feeders and prefer to bite humans.