Greater Sage Grouse Test Positive for West Nile Virus in Colorado

The Colorado Division of Wildlife (DOW) 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 are 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 his team of researchers are studying sage grouse in the Danforth Hills, Cold Springs Mountain, and Axial Basin areas of Moffat County. There currently 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 Center 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% of infected birds dying in the year of infection; however, more broad regional studies and studies on other species are still being conducted.
 
"We are still studying how West Nile Virus might impact grouse populations," Apa explains. "One study has found some grouse may be resistant to the virus, however studies on captive grouse exposed to the virus have seen significant mortality rates."
 
Colorado's dusky grouse (also known as blue grouse) season is currently underway and a limited greater sage grouse season begins Saturday, Sept. 9 in some parts of Colorado. Hunters should check the 2006 Colorado Small Game brochure for details on seasons.
 
According to 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. 
 
"Because of their outdoor exposure, game hunters may be at risk if they are bitten by mosquitoes in areas with West Nile virus activity," added Gershman. "If hunters anticipate being exposed to mosquitoes, they should apply insect repellent to clothing and skin, according to label instructions, to prevent mosquito bites."
 
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 Control reports that cooking meat to at least 165 degrees will kill the virus.
 
Hunters who find greater sage grouse, blue grouse or raptor carcasses that are in good condition can assist the DOW by collecting the carcass for testing. Hunters should only collect the carcass if they are wearing rubber gloves and have a sealable plastic bag in which to place the carcass. Carcasses should be frozen and delivered to the nearest DOW office.
 
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