The Colorado Division of Wildlife has confirmed that four greater sage grouse found dead in Northwest Colorado died from West Nile virus.
"It wasn't a surprise because scientifically we were aware that grouse were susceptible to West Nile virus," said DOW sage grouse researcher Tony Apa. "The virus had been discovered in other states, but up until now the grouse in Colorado have been fairly lucky."
Previously, only one other greater sage grouse in Colorado was a confirmed victim of the virus. That bird was found dead in 2004 in the Eagle South Routt population.
Apa and a team of researchers are studying sage grouse in the Danforth Hills, Cold Springs Mountain and Axial Basin areas of Moffat County. There are 160 radio-collared birds in the study areas. Researchers found four carcasses in July and August that were sent to the DOW wildlife health laboratory in Fort Collins. Three additional carcasses were too decomposed to be submitted for testing. Two recently discovered carcasses are in route to the lab for testing. Nearly 150 additional greater and Gunnison sage grouse are radio collared in other populations and are being monitored intensively, to detect any unusual mortalities.
West Nile virus has also been discovered in recent years in greater sage grouse populations in Montana, Wyoming, Idaho, Oregon, Utah and Alberta.
According to the Centers for Disease Control, West Nile virus is a flavivirus commonly found in Africa, West Asia and the Middle East. It is closely related to St. Louis encephalitis virus, which is also found in the United States. The virus can infect humans, birds, mosquitoes, horses and some other mammals. The virus is most frequently found in birds from the corvid family, such as crows and jays, but can also occur in raptors (owls, hawks, eagles, etc.) and members of the grouse family. West Nile studies in crows found significant localized mortality with 100 percent of infected birds dying in the year of infection; however, more broad regional studies and studies on other species are still being conducted.
Colorado's dusky grouse (also known as blue grouse) season is under way and a limited greater sage grouse season begins Saturday in some parts of Colorado. Hunters should check the 2006 Colorado Small Game brochure for details on seasons.
Dr. Ken Gershman, chief of the Communicable Disease Program at the Colorado Department of Public Health and Environment, there is no evidence that people can become infected with WNV from eating infected wild game meat.
Hunters are advised to use standard precautions when harvesting birds and all wild animals. Hunters should not harvest or touch animals that appear sick. Hunters should wear gloves when handling and cleaning animals to prevent exposure of blood to bare skin. Hands should be cleaned thoroughly upon completing cleaning of game, and hunters should not smoke, drink or eat while handling game. All game meat should be cooked thoroughly. The Centers for Disease Controls reports that cooking meat to 165 degrees or greater will kill the virus.