** FILE ** In this Friday, May 11, 2007, photo, a mosquito is sorted according to species and gender before testing for West Nile Virus at the Dallas County mosquito lab in Dallas. Scientists have been working on mathematical models to predict outbreaks for decades and have long factored in the weather. (AP Photo/LM Otero, File)

Photo by: LM Otero

** FILE ** In this Friday, May 11, 2007, photo, a mosquito is sorted according to species and gender before testing for West Nile Virus at the Dallas County mosquito lab in Dallas. Scientists have been working on mathematical models to predict outbreaks for decades and have long factored in the weather. (AP Photo/LM Otero, File)