Culex mosquitoes are often present in high numbers, are, found all over the globe, and are considered the main nuisance mosquito species. Culex mosquitoes can also transmit diseases such as West-Nile virus, filariasis and avian malaria. West-Nile virus, for instance, can cause fever and in severe cases meningitis or encephalitis in humans. Recent outbreaks of West Nile virus encephalitis in humans have occurred in several developed countries, including the United States and southern Europe. Culex mosquito control is largely based on area-wide larviciding (mostly with chemical insecticides), which is threatened by increasing insecticide resistance and environmental concerns of the public.
Countries / areas at risk of West Nile Virus, 2009
