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After one year of surveillance, contagious hoof disease was detected in 25 local elk; Index Herd Is In Smith River-Fort Dick Area, CDFW Scientists Say | Wild rivers outpost

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Jessica Cejnar Andrews / Today at 2:58 pm

After one year of surveillance, contagious hoof disease was detected in 25 local elk; Index Herd is in the Smith River-Fort Dick area, CDFW scientists say


A male Roosevelt elk shows off its antlers in a local field. File photo: Jessica C. Andrews

Previously:

• CDFW scientists hope Elk Hunt samples will help shed light on chronic hoof disease in the local herd

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A debilitating hoof disease that manifested in three elk in Del Norte County last year has been confirmed in more than 25 other animals, according to wildlife biologists in the state.

After working with hunters to provide samples, wildlife biologists say the Roosevelt elk index herd infected with treponema-associated hoof disease in California is in the Fort Dick-Smith River area, although that sporadic cases have been reported elsewhere in Del Norte and Humboldt counties.

“We are working to reduce the density of elk in conflict areas, one of those in the area where the index herd is located,” said Carrington Hilson, elk biologist at the California Department of Fish and Wildlife. Wild rivers outpost Tuesday. “We work in collaboration with our hunters. Last year we had 97 percent hunter compliance, basically 97 percent of our hunters who were successful in harvesting an elk gave us samples so that we could examine those hooves and send them in for further diagnostic testing. when it was justified.

Treponema-associated hoof disease, or TAHD, is associated with a strain of bacteria that causes digital dermatitis in livestock, CDFW veterinarian Emma Lantz told Del Norte County supervisors in April 2020. Described for the First seen in Washington in 2007 and 2009, TAHD can lead to deformed hooves, lameness, and general ill health in elk. It has since spread to elk in Oregon, Idaho and California.

In California, TAHD has been confirmed in Roosevelt elk, Lantz said. There have also been confirmed cases in Rocky Mountain elk in other states, she said.

Since the first two detections of the disease last year, the CDFW has launched a comprehensive disease surveillance plan and will release results from its first year soon, Lantz said. The plan also includes potential options to manage the disease, she said, although biologists are still examining basic questions such as how TAHD is transmitted.

“One of the main risk factors that has been proposed is the high density of animals, which can contribute to the development of disease in animals,” Lantz said. “Euthanizing animals for their welfare if they are obviously lame or lame and increasing the number of (hunting) tags available in an area are options. These can help both of us.

Scientists at Washington State University have discovered a way TAHD can be spread. According to research conducted by Professor Margaret Wild and her students at the WSU Elk Hoof Disease Research Program, healthy elk can contract the disease by walking on soil contaminated with other infected hooves.

“Our preliminary results indicated that TAHD can be transmitted to otherwise healthy elk through exposure to soil contaminated with affected elk hooves,” Wild said in a WSU press release on September 16. . the condition or exposure to chemicals promotes disease, but our results show that infection can occur without these additional insults.

Wild and his students studied six healthy elk calves captured in central Washington and brought to specially constructed biosecure stalls with their own feeders and waterers, according to the WSU press release. Wood chips were used as bedding for part of the stall, while soil in an herbicide-free area near Mount St. Helens covered a quarter, the statement said.

WSU researchers exposed four of its six elk calves to hooves infected with TAHD, according to the press release. The other two elk were exposed to uncontaminated hooves.

“On treatment days, the hooves were thawed, sampled for confirmatory diagnostic testing, then chopped and mixed with soil to make a treatment mix,” the WSU press release states. “The mixture was then placed in the elk pen. To ensure contact between the foot and the contaminated soil, about a teaspoon of the preparation was also placed on the toes on each of the two feet of each moose and it was held in place with a wrap.

The elk were treated at two to four week intervals between October and March, according to the WSU press release.

The researchers noticed early lesions between two to three months of treatment and at four months all four had moderate grade infections “indistinguishable from those found in wild elk.” The four treated elk were euthanized, the statement said.

The two elk treated with a soil mixture from uncontaminated hooves were not infected with TAHD, according to the press release.

Having research and data showing TAHD is transmitted through contaminated soil is a big step towards understanding the disease, Lantz said. But this type of study can only be done at a research center like WSU, she said.

Since there is no test that can be performed, diagnosing TAHD in wild elk is difficult, Lantz said. Determining if an animal is sick includes a visual inspection of its hooves as well as a microscopic examination, which requires dead animals, she said.

“This is where the compliance of the hunters, in terms of bringing us samples, has been invaluable statewide,” Lantz said. “They allowed us to sample a lot more animals than we could have done otherwise.”

According to Hilson, biologists also use spotting scopes and binoculars to examine elk herds and identify infected animals. Those who are at an advanced stage of the disease often have hoof capsules that have come loose, she said. While it is easy for biologists to determine that the elk is suffering from poor health, there is no way of knowing if it is infected with TAHD until samples are sent to the lab. , Hilson said.

Although the general hunt ended on September 23, the elk hunt continues under the CDFW’s Shared Habitat Alliance for Recreational Enhancement program, or SHARE program. This period runs until the end of December, Hilson said. CDFW will collect samples collected by hunters at its Lake Earl checkpoint, she said.

Carrington and Lantz are also asking the general public to keep an eye out for lame or lame elk and submit a mortality report on the CDFW website.

“Once we receive these reports, we can send them to a biologist in the local unit and they can investigate,” Lantz said. “If they see an animal and it’s a very serious case or a serious welfare issue, we can target those for euthanasia or just for surveillance.”


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