NORWALK - State scientists, who say the West Nile virus has been striking earlier each year, have already begun testing this season.

Officials at a mosquito collection site in Norwalk and others throughout the state began testing for the virus Tuesday.

"If there's any early virus activity we are going to detect it. We know where all the hotspots are," says Dr. Theodore Andreadis, a medical entomologist.

Officials say that given the pattern of earlier onsets of the virus, they're urging people to be extra vigilant.