West Nile Virus is most often transmitted by mosquitoes and is spreading quickly across the US. The green states on the map above all have West Nile Virus activity; those in dark green have confirmed incidents of human infection. While the majority of those infected with West Nile Virus will not get sick, it is important to protect yourself and to recognize the symptoms.
About one in five people who are infected with West Nile Virus will develop a fever with other symptoms such as headache, body aches, joint pains, vomiting, diarrhea, or rash. Most people with this type of West Nile virus disease recover completely, but fatigue and weakness can last for weeks or months.
Less than 1% of people who are infected will develop a serious neurologic illness such as encephalitis or meningitis (inflammation of the brain or surrounding tissues). The symptoms of neurologic illness can include headache, high fever, neck stiffness, disorientation, coma, tremors, seizures, or paralysis. People with certain medical conditions, such as cancer, diabetes, hypertension and kidney disease are also at greater risk for serious illness.
Recovery from severe disease may take several weeks or months. Some of the neurologic effects may be permanent. About 10 percent of people who develop neurologic infection due to West Nile virus will die.
No vaccine or specific antiviral treatments for West Nile virus infection are available. Over-the-counter pain relievers can be used to reduce fever and relieve some symptoms. In severe cases, patients often need to be hospitalized to receive supportive treatment, such as intravenous fluids, pain medication, and nursing care.
Avoiding West Nile Virus
The most effective way to avoid West Nile virus disease is to prevent any mosquito bites. These tips from the CDC will help.
Use insect repellents when you go outdoors. The CDC recommends using repellents with at least one of the following ingredients:
- Oil of lemon eucalyptus (Do not use on children under three)
Always use repellents according to the manufacturer’s instructions. In addition, follow these tips:
- Do not allow children to handle or spray the product. When using on children, apply to your own hands first and then put it on the child. Avoid applying repellent to children’s hands because children frequently put their hands in their eyes and mouths.
- Use just enough repellent to cover exposed skin and/or clothing. Heavy application does not give you better or longer lasting protection.
- After returning indoors, wash treated skin with soap and water or bathe. This is particularly important when repellents are used repeatedly in a day or on consecutive days.
If you (or your child) get a rash or other reaction from a repellent, stop using the repellent, wash the repellent off with mild soap and water, and call a local poison control center for further guidance. If you go to a doctor, it might be helpful to take the repellent with you.
Wear long sleeves, long pants, and socks when outdoors. Mosquitoes may bite through thin clothing, so spraying clothes with repellent will give extra protection. Do not spray repellent on the skin under your clothing.
Keep mosquitoes from getting into your home. Install or repair screens on windows and doors to keep mosquitoes outside. Use your air conditioning, if you have it. Also, to reduce the number of mosquitoes on your property, be sure to empty standing water from flowerpots, gutters, buckets, pool covers, pet water dishes, discarded tires, and birdbaths on a regular basis.
Report dead birds to local authorities. Dead birds may be a sign that West Nile virus is circulating between birds and the mosquitoes in an area. By reporting dead birds to state and local health departments, you can play an important role in monitoring West Nile virus. State and local agencies have different policies for collecting and testing birds, so check with your state health department to find information about reporting dead birds in your area.