West Nile virus is a flavivirus that originated in eastern Africa but is now prevalent throughout many areas of the world. Typically this virus affects mainly birds, however, there have been epidemics in humans and horses in recent years. Mosquitoes become infected with West Nile virus when they bite a bird that is infected. Afterward, mosquitoes then go on to feed on humans and transmit the virus onto them. Infections cannot result from casual contact with an infected animal or human.
West Nile virus has an incubation period between two and 14 days. This is the amount of time from when a mosquito bites until they begin to see symptoms of West Nile. Many people will contract West Nile from a mosquito and only experience mild symptoms, such as a mild fever. For others, West Nile can be fatal.
West Nile virus certainly is frightening, but it’s just as important that people understand the level of risk that comes with these mosquitoes. Fewer than one percent of mosquitoes in any area that’s known for carrier mosquitoes actually carry the virus. Additionally, less than one percent of people that are bitten and infected by a mosquito will actually become seriously ill. Many simply suffer from flu-like symptoms for several days.