Ok since no one else will answer, I tried to get you guys to actually look for some facts, I'll answer the question that I posed.
When did West Nile Virus first show up in the U.S.
Here's the answer that I found
"West Nile is a mosquito-borne virus that primarily infects birds but can be spread to humans and other mammals. Its first outbreak hit New York City in the summer 2 years ago. Last year it spread to most states in New England and as far south as North Carolina. Now, the agent has also been found in dead birds in Georgia, Florida and Louisiana. 'It's made a big jump,' said virologist Robert Tesh of the University of Texas Medical Branch in Galveston.
And in New York City of all places. Nope you guys must be right, theres nothing to this. It must be naturally occurring... /sarcasm off
The first West Nile outbreak was actually three years ago, but what the hell.