Transmission
Dengue viruses are transmitted to humans through the bites of
infective female Aedes mosquitoes. Mosquitoes generally acquire the virus
while feeding on the blood of an infected person. Once infective a mosquito is
capable of transmitting the virus to susceptible individuals for the rest of its
life, during probing and blood feeding. Infected female mosquitoes may also
transmit the virus to the next generation of mosquitoes by transovarial
transmission i.e. via its eggs, but the role of this in sustaining transmission
of virus to humans has not yet been delineated. Humans are the main amplifying
host of the virus, although studies have shown that in some parts of the world
monkeys may become infected and perhaps serve as a source of virus for
uninfected mosquitoes. The virus circulates in the blood of infected humans for
2-7 days, at approximately the same time as they have fever; Aedes
mosquitoes may acquire the virus when they feed on an individual at this
time.