For the first time, chronic wasting disease in deer has been found in the Four Corners area after testing was done during the 2020 hunting season, reports the Colorado Department of Parks and Wildlife.
The prevalence of the disease appears to be low, CPW biologists said, but the disease must be carefully monitored.
CWD is a fatal neurological disease found in deer, elk and moose. During the 2020 deer season in Southwest Colorado, CPW authorized mandatory checks for all buck deer harvested by hunters.
In the area roughly from Dove Creek to Wolf Creek Pass, 18 deer of 1,489 checked tested positive.
It is the first time that CWD infected deer have been found in this location of Colorado, designated as Area 15. All hunters whose deer tested positive have been contacted.
“On the face of it the prevalence looks low, but CWD is 100 percent fatal, and we don’t want to see it continue to increase in our herds,” said Scott Wait, senior terrestrial biologist for CPW’s Southwest Region. “CWD infections are higher in males than females. If we want healthy herds, we need to use reasonable management to keep it in check.”
During hunting season, CWD testing stations were set up in Dolores at the Dolores Fire Protection District Station, at the CPW office in Durango and at the fairgrounds in Pagosa Springs. Every hunter was sent a letter of the requirement as a reminder to bring in the head to be tested.
Hunters presented their licenses and an accurate location where the animal was harvested.
The head of the animal should be removed 4 inches below the lower jawbone and the base of the skull. Heads should be tested as soon as possible, preferably within five days of harvest. Heads should not be frozen.
At the Dolores testing station, hunter Garet Talley of Cortez pulled up and brought over the head of the buck he shot in the Glade.
CPW staffer Chad Johnston filled out paperwork and pinpointed the map location of where it was harvested. He then got to work cutting out the lymph nodes, tonsils or brain stem. The whole process took 10 to 15 minutes, and the samples are bagged and tagged.
“I’ve done 10 today, 45 since we started,” he said Oct. 27. “The study provides important baseline data, and we get to hear all the hunting stories too.”
The deer heads are returned to the hunter, and the samples are sent to a lab in Fort Collins for testing.
CWD spreads through direct or indirect contact between animals. The disease agents, called prions, are present in saliva, feces and carcass parts of infected animals.
These prions also can stay in the soil for long periods of time which is why it is also very important to monitor and control herds that are infected in order to minimize long-term contamination of their ranges with CWD prions.
CWD tends to be more prevalent in bucks, said area wildlife manager Matt Thorpe, and it is likely spread through the rut.
Parks and Wildlife has been monitoring the prevalence of CWD throughout Colorado for more than 20 years, said spokesman Joe Lewandowski. In some areas of the state where a high incidence of CWD is found, CPW will increase the number of licenses available to hunters.
Harvesting more animals is a management tool that can help reduce the spread and the number of infected animals. Currently, big game managers in Area 15 are evaluating the CWD results to determine how many licenses will be available during the 2021 deer hunting season.
Big game herds are managed using objectives for population, male-female sex ratio and habitat conditions. In Area 15, licenses will be adjusted to meet plan parameters.
For locations west of Durango, the number of buck licenses will be increased to meet objectives and to reduce CWD infections. East of Durango, the deer herd is within its objective range.
Although there is no proof that humans can contract CWD by eating the meat of an infected animal, CPW and the Colorado Department of Public Health and Environment recommend that the meat not be consumed.
CPW’s Area 15 is divided into four herd management areas, those are further divided into game management units. Following are the testing totals and prevalence rates for adult male deer tested from each:
GMUs 70, 71, 711: 13 of 424 deer tested positive, 3%. The units, approximately, are located south of Norwood and north of Cortez.
GMUs 72 and 73: four of 175 deer tested positive, 2%. The units are located immediately east and west of Cortez.
GMUs 74 and 741: none of the 95 deer tested positive, no CWD detected. The units, generally, are located from Red Mountain Pass south to the New Mexico state line and from the Animas River to the west boundaries of San Juan and La Plata counties.
GMUs 75, 751, 77, 771 and 78: one of 578 deer tested positive, .1%. The units are located east of the Animas River to Wolf Creek Pass.
CPW biologists can’t say why there is a higher incidence of infection in GMUs 70, 71, 711, Lewandowski said. It is notable that more infected deer have been found in the agricultural areas north of the Montrose-Delta area, which is similar to the area where a higher incidence was found north of Cortez.
CPW will continue to monitor these GMUs into the future and voluntary CWD testing for deer will be available to hunters for the 2021 season for $25.
CPW will require mandatory testing of elk harvested during specific limited rifle seasons this fall.
There will be no charge for those tests and hunters who draw tags for those seasons will be informed of testing procedures next summer. CWD has never been found in elk in this area of Colorado.
For more information about CWD, go to: cpw.state.co.us/learn/Pages/ResearchCWD.aspx, or contact the Durango wildlife office at 970-247-0855.