Colorado's top West Nile virus fighter is warning that the disease could be back again for another year.

　　The mosquito-borne disease peaked in Colorado in 2003, with 2,947 cases statewide, mostly on the Front Range. Last year, it moved west, with 127 of the 292 statewide cases reported in Mesa County.

　　"The bad news is that the virus isn't going away," state health department epidemiologist John Pape said Monday.

　　The extent of the epidemic will vary depending on local moisture and temperatures, he said.

　　Mesa County, surrounding Grand Junction on the Colorado-Utah border, had a West Nile outbreak last year because of ideal weather and plenty of irrigation water to support a large mosquito population and plenty of humans to infect.

　　West Nile can inflict paralysis, brain damage or death, but 80 percent of those who catch it will show no symptoms. The elderly are especially vulnerable, Pape said.

　　Although mosquitoes are the primary culprits, the virus can also be transmitted through blood transfusions, organ transplants and breast milk and by a mother to her unborn child, he said.