West Nile Virus (WNV)

When it comes to mosquito-borne disease transmission, West Nile Virus (WNV) continues to pose the biggest threat to Lucas County residents. Historically found in Africa, Eastern Europe, West and Central Asia, and the Middle East, WNV first appeared in North America with an outbreak in the New York City metropolitan area in late summer 1999. WNV spread to the west and south and eventually reached Ohio in 2001, causing the deaths of several hundred birds. The first human illness in Ohio due to WNV occurred in 2002. WNV can now be found throughout the continental United States and the Western Hemisphere.

People get WNV from the bite of a mosquito that is infected with the disease from previously feeding on an infected bird. West Nile virus is not transmitted from person to person. People do not build up enough virus in their bloodstream to infect other mosquitoes and are “dead-end” hosts that do not continue the disease cycle. In Ohio, the northern house mosquito, Culex pipiens, is believed to be the primary vector to humans. Only a small proportion of other mosquito species can be infected with WNV. Mosquitoes become infected after biting infected wild birds that serve as the primary host of the virus. Members of the Corvidae bird family, especially crows and blue jays, are very susceptible to WNV and frequently die from the disease. Many other kinds of birds may also become sick and die from the disease. Horses can also become infected but, WNV is extremely rare in other animals, such as dogs.

Most people infected with WNV display no symptoms of illness, but some may become ill 3 to 15 days after the bite of an infected mosquito. Mild symptoms of the disease may include a fever, headache, and muscle aches. About 1 out of 150 people develop more severe symptoms, such as high fever, severe headaches, stiff neck, confusion, or muscle weakness, which can result in hospitalization and even death. Those inflicted with severe cases of WNV often experience lifelong complications and side effects from the illness.

CDC West Nile Virus website