West Nile virus is an infection carried by mosquitoes. This infection flares up every summer and fall. In the US, 1590 cases of West Nile virus have been reported in 2012 by the end of August. There have been many media reports describing worst case scenarios of meningitis and encephalitis. I'd like to present a more balanced piece on West Nile virus, it's symptoms and it's prevention.
The virus was first discovered in Egypt in the late 1930's. It came to the US around 1999. The great majority of people who contract West Nile virus don't even know they're infected. Their symptoms are that mild. This is called "asymptomatic disease." According to the CDC, this asymptomatic form of the illness makes up 80% of cases. Nearly all of the remaining 20% have "mild disease." Symptoms of mild infection include fever, headache, nausea and vomiting. You can also have swollen lymph nodes and a rash. Symptoms appear 2-14 days after a mosquito bite. They generally last 4-5 days, but can persist for weeks.
It is only 1 in 150 cases that develop meningitis or encephalitis. The CDC lists the following symptoms for these severe cases of West Nile virus: high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness and paralysis. Such severe cases of West Nile virus can last for several weeks, leading to permanent neurologic damage or even death. If you have these symptoms, have someone get you to the nearest emergency department right away. While these cases are clearly the minority (less than 1% of infected individuals) they are important because of the damage they cause. While they are not a reason for widespread panic, they show us that we should not take this infection lightly. Treatment for West Nile virus is supportive. That means there is no specific medication to get rid of the virus. However, physicians and nurses can provide treatment that helps symptoms and support of the respiratory and gastrointestinal symptoms.
The West Nile virus was discovered in Egypt in the late 1930's. It has been here in the US since 1999. It is preventable. As the virus is carried by mosquitoes, prevention revolves around them. At this time, there is no immunization for West Nile virus. Many large communities are spraying for mosquitoes. This has been proven to work. There are also things we can do as individuals. We can get rid of standing water. Such water is a breeding ground for mosquitoes. Freshen water in pet's bowls frequently. Change the water in bird baths weekly. Most importantly, wear insect repellant. If you want to hunt and fish, that's fine. Make insect repellant part of your gear. It should contain a proven pesticide, such as DEET, Picardin, Oil of Lemon Eucalyptus, or IR3535. Mosquitoes are most prevalent at dusk and dawn. Wear long sleeves and long pants at those times. Do you want to go sit outside and watch the Friday night football game? Fine. Wear long sleeves, long pants and insect repellant. And, enjoy the game.
Hopefully, you now have a good understanding of West Nile virus, it's symptoms and it's prevention. Please understand that most cases don't need treatment. While I don't think it's necessary to hide indoors, I do think it is wise to respect this infection. As always, if you have questions, don't hesitate to contact your healthcare provider.
~Dr Nan N~