One of the mosquito-transmitted diseases that has received a lot of media attention is West Nile virus. Contrary to popular belief, most cases of West Nile virus are not severe. Accrording to the CDC, about 1 in 150 people exposed to West Nile develop severe illness from West Nile, generally these cases are among the elderly and very young children. However, the majority of West Nile virus cases are unreported since the symptoms are unspectacular.
West Nile virus mainly affects birds, but it can affect humans if a mosquito bites a human. While there are other potential ways humans can catch West Nile virus, a mosquito bite is the prevailing method of exposure. A common way communities are alerted to a potential West Nile outbreak is when a dead bird is found that likely had West Nile.
Most people who are exposed to West Nile will not develop any symptoms at all. However, up to 20% can develop mild symptoms (and then there is the small minority that may develop severe symptoms). Mild symptoms are similar to flu symptoms, such as headache, nausea, fever, etc. These symptoms may last a few days or a few weeks, depending on the person.
It takes anywhere from three days to two weeks for West Nile to incubate. The main method to prevent West Nile is for communities to undertake mosquito extermination when a dead bird with West Nile is found and for citizens to be vigilant and use mosquito repellent when they are outdoors.