Sifter

This nasty little invader, which infiltrates the human population via mosquitos, arrived in Northern California in 2004 and infected 935 Californians and 3,046 California birds in 2005. Though there have been no reported human cases in California in 2006 so far (only about 1 percent of cases develop into serious illness), disease experts have found 10 dead birds with the virus. As we look ahead to the 2006 West Nile Virus season, think on these cumulative numbers from 2005.

Cumulative California cases for 2005

County, Human cases, Dead bird infections

Butte 25 79
Glenn 13 30
Shasta 1 28
Sutter 9 9
Tehama 4 47
Yuba 6 12
Others 877 2,841

Source: U.S. Geological Survey, with data from the Centers for Disease Control and Prevention, as well as www.westnile.ca.gov/2005_summary.htm