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Spokane, Washington  Est. May 19, 1883

Elk hoof disease research in hands of Washington State University Veterinary School

An elk shot during an August hunting season near Vader, Washington, had a hoof deformed by foot rot. (Courtesy of Larry Gitch)
By Rich Landers for The Spokesman-Review

Washington State University is poised to take over inconclusive research on elk hoof disease that’s been plaguing elk west of the Cascades in Washington and Oregon.

The disease also has been found in elk in portions of the Blue Mountains and the Wallowa Mountains near the Idaho border.

The scientist selected to lead the WSU research will have years of state-collected data with which to work.

The Legislature allocated $3 million to WSU for two years of work on elk hoof disease, said Charlie Powell, spokesman for the WSU College of Veterinary Medicine.

The school created a lengthy job description in July for a new research scientist to head the program. The original deadline for applications was Monday. A selection from applicants could be made by February, “but we plan to accept applications as long as it takes to get a fully qualified person,” Powell said.

As of this week, seven applications were being reviewed.

Wildlife scientists are still many steps behind the advancement of the disease, which is similar to hoof rot found and reasonably controlled in livestock. But even if a treatment is found, it would be difficult to deliver to free-roaming elk, state officials say.

The outbreak of painful elk hoof deformities ramped up in 2007 within two of Washington’s 10 elk populations – the Willapa Hills and Mount St. Helens herds.

“Well over half” of the elk in this hardest-hit region of southwestern Washington appear to have hoof disease, said Brock Hoenes, Washington Department of Fish and Wildlife statewide elk specialist

In the past two years, elk hoof disease has begun advancing into the Olympic Peninsula herd in the Skokomish River Valley and the North Cascades herd in the Skagit River Valley.

A 16-member Technical Advisory Committee of experts from multiple states, agencies and universities agreed in 2014 the disease is associated with treponeme bacteria, which are known to cause digital dermatitis in cattle, sheep and goats.

Critics of the state’s inability to find a treatment for the disease have wanted the Washington Department of Fish and Wildlife to look into environmental factors, such as the possible impacts of aerial spraying practices used by the timber industry.

“It’s difficult to tease out other environmental factors separate from the disease,” said Kyle Garrison, who became WDFW’s hoof disease coordinator in July. “How it manifests itself remains uncertain.”

Finding a cure and applying a treatment to a wild elk population seems even further out of reach, he said.

While state researchers are learning more about the disease they call “treponeme-associated hoof disease” (TAHD), little of it is encouraging.

“It progresses pretty rapidly,” said Dr. Kristin Mansfield, state wildlife veterinarian.

Citing four years of research with radio-collared elk, some of which have been recaptured for evaluation, she said no cases convincingly indicate that elk can recover after being infected.

“In the past two years,” she said, “we’ve confirmed that affected animals produce an immune response, but it doesn’t seem to be protective.”

No evidence suggests TAHD poses a risk to humans, officials say. Tests of muscle tissue of affected game have found the disease in the hooves does not extend to the meat or organs.

How the disease spreads is not clear, Mansfield said. Scientists speculate that the bacteria are transferred in moist soil via the hooves of elk or other animals such as sheep and cows.

Other states are watching the progress of the disease.

“We were pretty keenly interested in a couple reports (of hoof disease) last winter that we investigated,” said Jon Rachael, Idaho Fish and Game Department state game manager. “They were tested at the Idaho Health Lab and turned out to be an entirely different, noncontagious situations. To this point, we have not had any confirmed hoof rot cases in Idaho.”

A 35 percent decline in the Mount St. Helen’s herd – one of Washington’s two largest elk herds – has been documented over the past four to five years, said Hoenes, the state’s elk specialist. The role of hoof disease is difficult to calculate since the state had been orchestrating a hunter harvest of more than 1,000 cow elk in the core area to bring the herd into balance with habitat capacity, he said. Poor nutrition also played a role in the decline, he said.

“Some people are drawing a cause-and-result relationship with TAHD,” Hoenes said, but the role of the disease in the herd’s decline couldn’t be ascertained.

“A lot of wildlife questions take a long time to answer,” Garrison said.

More than 200 volunteers were recruited in 2015 to drive southwestern Washington survey routes in an effort to quantify prevalence and distribution of the disease.

The volunteers found at least one limping elk in 48 percent of the elk groups surveyed, Hoenes said, although he noted that TAHD isn’t the only factor that could make an elk appear to be limping.

A spring 2017 aerial survey over the same areas detected a limper in 42 percent of the elk groups found, he said, noting that number “increased to approximately 75 percent within the endemic area.”

Of the 2,500 respondents to a 2016 survey of Western Washington elk hunters, 6 percent said they harvested elk with deformed hooves. The number increased in the Willapa Hills to 15 percent and up to 22 percent overall in the Mount St. Helens area.

Reports of hunters killing elk with deformed hooves increased up to 53 percent in a hot spot in the northwest portion of the Mount St. Helens herd and the southeast corner of the Willapa Hills elk herd area.

Through two years of monitoring, annual survival rates have ranged 59-68 percent for radio-collared elk with hoof disease as compared with 78-79 percent for non-TAHD elk, Hoenes said.

Researchers have attributed 44 percent of mortalities for diseased elk to malnutrition and have attributed an additional 20 percent to cougar predation. In comparison, only 9 percent of mortalities for nondiseased elk have been attributed to malnutrition and 9 percent to cougar predation, Hoenes said.

“The leading cause of death for nondiseased elk has been human harvest – 55 percent – whereas just 9 percent for diseased elk,” he said. “Undoubtedly, the debilitating effects of TAHD have contributed to the proportion of diseased elk dying of malnutrition.”

All of the elk in the hardest-hit area are faced with serious nutritional limitations, resulting in strongly depressed pregnancy rates, he said.

Seeking a cure that wildlife scientists haven’t able to deliver, the 2017 Washington Legislature passed a bill sponsored by Sen. Kirk Pearson, R-Monroe, that shifted authority for elk hoof disease research from the WDFW to Washington State University.

WDFW had appropriated $480,000 to elk hoof disease efforts in the past two years, with $87,000 from the legislature and the rest from federal funds and proceeds of an elk tag auction and raffles.

It will be up to the new WSU research leader to determine whether studies would look into the possible connection of hoof disease to forestry practices and chemicals, said Powell, WSU’s spokesman.

So far, WSU’s new role has involved preparing lab space, building a new website in addition to the one maintained by WDFW, and planning public outreach and social media training.

“We want to communicate with stakeholders and satisfy public interest in the effort to find a cure for this debilitating disease,” Powell said.

“It’s a huge job. It’s a multifaceted disease, not just a simple infection. It’s going to require a person at WSU with ability to look at epidemiology and all the data and information gathered in order to chart a path forward.”