ATLANTA, Oct 11, 2002 (United Press International via COMTEX) -- The nation's death toll from West Nile virus was at least 160 in 2,946 cases as of Friday, the Centers for Disease Control and Prevention reported.

Illinois led the nation with West Nile deaths at 41, followed by Michigan with 28 and Louisiana with 15.

The mosquito-borne disease is believed to have infected the nation's blood supply and two companies have started testing a chemical they hope will sterilize blood, killing any viruses and bacteria, including West Nile.

The new technology is being tested by Cerus Corp. of Concord, Calif., and V.I. Technologies of Watertown, Mass.

Cerus has won permission in Europe to sterilize platelets, a component of blood, but would still need permission from the U.S. Food and Drug Administration before the process could be put into widespread use in the United States.

West Nile also has taken a toll on the U.S. bird and horse populations. Officials at the Milwaukee County Zoo said their facility has been the hardest hit.

Dominic Travis, a veterinarian at Chicago's Lincoln Park Zoo and a member of the American Association of Zoo Veterinarians, said that West Nile has turned up in at least 35 species and possibly as many as 70, including a lizard called the crocodile monitor. More than 100 zoos participated in the survey.

The Milwaukee zoo has lost eight Humboldt penguins to the virus and 12 others have shown symptoms.

In Canada, where there at least one person has died of West Nile, the Toronto Zoo has lost two koalas on loan from the San Diego Zoo.