West Nile Virus

West Nile Virus (WNV) is a viral disease transmitted by mosquitoes. It was first identified in the West Nile region of Uganda in 1937, and first detected in the United States in 1999 on the east coast. The Culex pipens mosquito is the primary carrier of WNV. Less than 1 percent of mosquitoes are infected with WNV. There is currently no vaccine to prevent the disease.

Greene County has not had a confirmed case of WNV in a human since 2008, when one case was reported.

Symptoms
  • Typically develop 3 to 15 days after exposure
  • 4 out of 5 (80 percent) of those who are infected will not know due to mild symptoms
  • Those who do develop more pronounced symptoms may expereince fever, headache, body aches, nausea or vomiting (similar to the flu). Symptoms can last for as short as a few days, though even healthy people have become sick for several weeks
  • About one in 150 people (less than one-tenth of 1 percent) infected with WNV will develop severe illness. Symptoms can include high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness and paralysis
  • Doctors believe that infection produces lifelong immunity
  • WNV is not contagious through person-to-person contact
Prevention Tips
  • Many mosquitoes are most active at dusk and dawn. Be sure to use insect repellent and wear long sleeves and pants at these times or consider staying indoors during these hours
  • Use an insect repellent as directed and that contains DEET or pyrethrin (the synthetic form of a natural insecticide found in chrysanthemums)
  • Make sure you have good screens on your windows and doors to keep mosquitoes out of your home
  • Get rid of mosquito breeding sites by emptying standing water from flower pots, buckets and barrels. Change the water in pet dishes and replace the water in bird baths weekly. Drill holes in tire swings so water drains out. Keep children's wading pools empty and on their sides when they aren't being used
  • If you have a rain barrel, use a screen to keep mosquitoes out of the water. A mosquito "dunk" is a time-release tablet that contain a bacterial agent which kills mosquito larvae, but does not affect people, animals or plants
There were more cases of West Nile Virus reported in 2012 than any previous year in the US. As of early October 2012, there were nearly 3,700 reported cases, including 163 deaths. Seven states saw 65 percent of the cases in 2012: Texas, South Dakota, Michigan, Mississippi, Oklahoma, California and Louisiana. Texas alone was the location of 35 percent of those cases.

For more information and the latest statistics, visit the Centers for Disease Control and Prevention's West Nile Virus homepage.