MARTINEZ, CA - APRIL 09:  A mosquito sits on a stick April 9, 2009 in Martinez, California. Unseasonably warm weather for Northern California in January appears to have brought  female mosquitos out of hibernation and have started to breed months ahead of the normal breeding season. Several groups of mosquitos found in a marsh near the Contra Costa County town of Martinez have tested positive for the West Nile Virus prompting county officials to do more testing and releasing mosquito fish in abandoned pools around the county.  (Photo by Justin Sullivan/Getty Images)