Let me tell you what it is. I didn't know whether to put it in current events or educational, but now I do since I did a little research.

What is West Nile virus?
West Nile virus is a flavivirus of African origin that can be spread to humans and other mammals via mosquitoes, causing encephalitis and flulike symptoms, with some fatalities.

What are some of the symptoms?
Mild symptoms of the virus which happens 3 to 14 days after a mosquito bite includes a fever, headaches, body aches, or pain in your eyes, a rash, usually on the chest, back, and arms, feeling very tired, not feeling hungry, feeling sick to your stomach or throwing up, swollen glands (lymph nodes), in rare cases. In a mild case of West Nile the symptoms usually last up to 3 to 6 days.

Symptoms for more severe case include headaches, high fever, a stiff neck or paralysis, confusion, reduced attention to surroundings, tremors, convulsions, or muscle weakness, a coma, in rare cases West Nile virus can cause death. My source doesn't tell me how long the severe symptoms last, sorry.

How can it spread?
The most common way you can get it, is by a mosquito bite. Yes they're pesky little insects, but now you have a really good reason to kill them. Animals can also carry them humans and birds can as well. You have to be careful your pet could have it.

How long has it been going on?
It is commonly found in Africa, Eastern Europe, West Asia, and the Middle East, but until 1999 had not been found in the Western Hemisphere.

Am I vulnerable to it?
Most people over 50 have a higher risk of being diagnosed with it. Also less than 1% of mosquitoes in the area have West Nile virus.

Sources: For the definition, for the symptoms, how it can spread, read more at Kids health.