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Friday, March 7, 2014
West Nile virus (WNV) is a potentially serious illness that flares up in the summer and continues into the fall. It is now in most of the United States. The most important way people become infected is through the bite of an infected mosquito. You can reduce your chance of being infected with WNV by avoiding mosquito bites.
The easiest and best way to avoid WNV is to prevent mosquito bites.
More information is available at Insect Repellent Use and Safety.
These symptoms may last several weeks, and neurological effects may be permanent.
Symptoms can last for as short as a few days, though even healthy people have become sick for several weeks.
More information is available at Symptoms of WNV.
Infected Mosquitoes. Most often, WNV is spread by the bite of an infected mosquito. Mosquitoes become infected when they feed on infected birds. Infected mosquitoes can then spread WNV to humans and other animals when they bite.
Transfusions, Transplants, and Mother-to-Child. In a very small number of cases, WNV also has been spread through blood transfusions, organ transplants, breastfeeding and even during pregnancy from mother to baby.
Not through touching. WNV is not spread through casual contact such as touching or kissing a person with the virus.
People typically develop symptoms between 3 and 14 days after they are bitten by the infected mosquito.
There is no specific treatment for WNV infection. In cases with milder symptoms, people experience symptoms such as fever and aches that pass on their own, although even healthy people have become sick for several weeks. In more severe cases, people usually need to go to the hospital where they can receive supportive treatment including intravenous fluids, help with breathing and nursing care.
If you develop symptoms of severe WNV illness, such as unusually severe headaches or confusion, seek medical attention immediately. Severe WNV illness usually requires hospitalization.
Milder WNV illness improves on its own, and you do not necessarily need to seek medical attention for this infection though you may choose to do so.
If you are a pregnant woman or nursing mother and you develop symptoms that could be WNV, talk to your doctor. The risk that WNV may present to a fetus or an infant infected through breast milk is still being evaluated. More information is available at WNV, Pregnancy, and Breastfeeding.
People over 50. If you are over the age of 50, you should take special care to avoid mosquito bites. You are more likely to develop serious symptoms of WNV if you do get sick.
Being outside. The more time you are outdoors, the more time you could be bitten by an infected mosquito. Pay attention to avoiding mosquito bites if you spend a lot of time outside, either working or playing.
Medical procedures. Risk through medical procedures is very low. All donated blood is checked for WNV before being used. The risk of getting WNV through blood transfusions and organ transplants is very small and should not prevent people who need surgery from having it. If you have concerns, talk to your doctor.
Pregnancy and nursing do not increase risk of becoming infected with WNV.
What Should I Do if I Find a Dead Bird?
Do not handle the bird with your bare hands. Contact your local health department for instructions on reporting and disposing of the body. They may tell you to dispose of the bird after they log your report. More information is available at WNV and Dead Birds.
West Nile Virus Fact Sheets - English and Spanish (OSU Extension - Ohioline)
This article is based on the CDC Factsheet, West Nile Virus: What You Need to Know, last updated August 30, 2012.
Last Reviewed: Sep 04, 2012
William JA Saville, DVM, DACVIM, PhD
Professor and Chair
College of Veterinary Medicine
The Ohio State University