Ongoing surveillance and testing will be key to identifying and managing the spread of a fatal wildlife disease that was recently detected in two deer near Cranbrook, according to a provincial wildlife biologist.
Cait Nelson recently delivered a pair of public presentations, including an online discussion hosted by the BC Wildlife Federation and a forum in Cranbrook organized by the B.C. chapter of the Backcountry Hunters and Anglers.
The topic was Chronic Wasting Disease (CWD), an infectious and fatal neurological disease affecting deer, elk, moose and caribou species (cervids) that is caused by abnormal proteins called prions, that accumulate in tissues, particularly the brain.
CWD can be transmitted by shedding infected prions through urine, feces, and saliva, and can also enter the environment through infected carcasses, tissues, or contaminated material such as hay, or even through direct animal-to-animal contact.
It is fatal to cervids, and while there are no known cases of animal-to-human transmission, public health officials recommend that people do not eat any animals infected with CWD.
Nelson emphasized the importance of testing samples from harvested cervids in order to track the potential spread of the disease.
“The role of hunters is key to this and I hope that’s come across in this presentation, that hunting is the most important tool in CWD management,” said Nelson, during the BHA presentation in Cranbrook on Feb. 28. “Every single management plan needs to have a hunting component.
“My ask, my request is please don’t stop hunting in these CWD areas. We need to continue the hunting pressure in these areas, because without it, CWD will get away on us and at this point, in an early outbreak, the chance of harvesting a positive deer is pretty low.
“We’re in a pretty good place still, where there’s a small proportion of animals infected, so we need to keep that pressure on, we need those samples and the information so we can move forward in this plan with the right information, to make smart decisions about it.”
On Jan. 31, lab results confirmed two samples collected from deer tested positive for CWD. One was a male mule deer harvested in the South Country region east of Lake Koocanusa, while the other was a female whitetail deer that was a roadkill on Highway 3 south of Cranbrook.
Since then, the province has implemented mandatory CWD testing, as well as ordering restrictions on transporting and disposing roadkill cervids in the immediate region, which are identified as Management Units 4-2, 4-3, 4-4, 4-5 and a portion of 4-22.
Nelson said similar restrictions for hunter-harvested cervids are anticipated once the hunting season gets closer, however, there are lots of conversations and consultations with stakeholders to come.
Providing a sample of hunter-harvested deer species for testing is now mandatory in Management Units 4-1 through 4-8 and 4-23 to 4-25. While not mandatory for elk and moose in those same regions, the province encourages voluntary submission for testing.
Additionally, the province is also requesting hunters to now provide specific coordinates of where animals were harvested, in order to better track where the disease may be spreading.
Testing for CWD isn’t as easy as analyzing fecal or urine samples.
The only way to definitively test for the disease in deer is by extracting tissue from the back of the throat, tonsils and lymph nodes, while elk and moose samples need to include lymph nodes and a portion of the brain stem, according to Nelson.
Testing turnaround times can take up to six weeks, as samples were historically analyzed out of a lab in Saskatchewan, however, an agriculture facility in Abbotsford is now ramping up capacity to take on CWD testing, which should provide much quicker results.
Testing is important because there’s no visual indicator of an animal being affected by CWD; an animal can look perfectly normal, yet it could be infected with the disease.
CWD was initially detected in the United States in captive deer in Colorado nearly 50 years ago, which spread to free-ranging animals through the American West, Midwest, and into Canadian provinces including Manitoba, Saskatchewan and Alberta.
U.S. officials discovered CWD in deer in Libby, Montana, in 2019.
B.C. has had a CWD surveillance program in place since 2001, which was recently updated last year. As part of efforts to prevent the disease from gaining a foothold in the province, the government banned the importation of at-risk portions of harvested deer from outside B.C., which was implemented in 2010.
Nelson’s presentation included long term population health trends from other jurisdictions in North America that have implemented strategies to manage the disease, as well as lessons learned.
For example, mule deer, whitetail deer and elk populations in places such as Colorado and Wyoming have declined anywhere from 3-20 per cent per year, in populations that would otherwise be stable without CWD. Over the last two decades, that has led to overall population declines of up to 40-50 per cent, Nelson said.
Nelson likened CWD management to a sliding scale ranging from more extreme action, such as non-selective increase in harvest capacity to reduce population density, to monitoring and maintaining the status quo.
In terms of drastic measures, Nelson noted that large-scale culling programs initiated in other jurisdictions in the past to eradicate CWD were unsuccessful and are now publicly unpalatable.
“What we’ve learned from other places…is that the large scale culling that was applied in Alberta and other places 20 years ago failed, and was very unpopular and is no longer recommended,” Nelson said.
“And so when we’re talking about sharp shooting and culling, the recommended approach now is very small scale and very targeted.”
Illinois was held up as an example where CWD has been effectively managed through actions to reduce population densities by increased hunter harvest opportunities and targeted small-scale culls.
Audience questions ranged on testing methods, potential transmission through hay or livestock and what impact, if any, scavengers and predators have the disease’s spread.
Following an audience question relating to urban deer, Nelson noted that urban deer populations are at higher risk with more frequency of contact points and a decrease in pressure from predators.
“I know there are some conversations happening right now, in terms of managing urban deer in the province and in this area,” Nelson said, “and now that we have CWD in the area, then that’s just an extra rational for managing those populations and for us to access those samples if there are infected animals in those urban deer populations, we need those samples to confirm that.”
The introduction of CWD into British Columbia is one element of ongoing concerns with wildlife management from local politicians and hunting and conservation advocates.
Tom Shypitka, MLA for Kootenay East with BC United, has campaigned for more financial resources into wildlife causes in the past, and also crafted a private members bill to create an independent funding model.
With the introduction of CWD into the southeast Kootenay, Shypitka and BC United leader Kevin Falcon urged “immediate action bolster British Columbia’s response capabilities,” in a joint statement issued March 1.
Specifically, BC United is pledging an emergency response fund to cover expenses such as operations, travel, regional depots and contracted resources, as well as making a commitment to establish a local, accredited laboratory to cut down on testing times.
“Chronic Wasting Disease represents a considerable threat to wildlife in British Columbia and given the disease’s capacity for rapid environmental transmission it is unfortunate the NDP has not updated response mechanisms accordingly,” reads the statement.
In response, Nathan Cullen, the Minister of Water, Land and Resource Stewardship, said the pr0vince is escalating and enhancing CWD testing.
“Chronic wasting disease can seriously impact deer, elk, moose, and caribou – that’s why a surveillance and response plan was put in place as the disease was detected in neighbouring jurisdictions,” said Cullen, in a statement. “Testing led to early detection of the disease in BC, and we are actively escalating our respond in collaboration with First Nations, local leaders, wildlife experts and organizations representing hunters, like the BC Wildlife Federation.
“Immediate restrictions on the transportation of carcasses are in place near Cranbrook, and testing is being escalated and enhanced. We will keep working with our partners to take additional steps to combat this disease and the impact to communities and wildlife.”