(Observations from 2012 to present.)
Limping = Red, Dead = Black
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Since 2008, reports of elk with deformed, broken, or missing hooves have increased dramatically in southwest Washington, with sporadic observations in other areas west of the Cascade Range. While elk are susceptible to many conditions that result in limping or hoof deformities, the prevalence and severity of this new affliction – now known as treponeme-associated hoof disease (TAHD) – suggested something altogether different.
Diagnostic research conducted by the Washington Department of Fish and Wildlife (WDFW) in conjunction with a panel of scientific advisors found that these abnormalities were strongly associated with treponeme bacteria, known to cause digital dermatitis in cattle, sheep and goats. Although this type of disease has plagued the dairy industry for decades, TAHD had never before been documented in elk or any other hooved wildlife species.
Since then, WDFW has continued to work with scientists, veterinarians, outdoor organizations, tribal governments and others through its Hoof Disease Technical Advisory Group and Public Working Group to develop management strategies for elk infected by TAHD.
Several aspects of TAHD in elk are clear:
- Susceptibility: The disease appears to be highly infectious among elk, but there is no evidence that it affects humans. TAHD can affect any hoof in any elk, young or old, male or female.
- Hooves only: Tests show the disease is limited to animals' hooves, and does not affect their meat or organs. If the meat looks normal and if hunters harvest, process and cook it practicing good hygiene, it is probably safe to eat.
- No treatment: Currently, there is no vaccine to prevent the disease, nor are there any proven options for treating it in the field. Similar diseases in livestock are treated by forcing them to walk through foot baths and cleaning and bandaging their hooves, but that is not a feasible option for free-ranging elk.
To date, WDFW has confirmed cases of elk afflicted with TAHD in Cowlitz, Grays Harbor, King, Lewis, Mason, Pacific, Skagit, Skamania, Thurston, Wahkiakum, and Whatcom counties. The disease is also suspected in populations of elk in Clark and Pierce counties. Preliminary efforts to formally estimate the prevalence and distribution of TAHD indicate the disease is most prevalent in Cowlitz, Wahkiakum, and the western half of Lewis county.
Since 2015, the Oregon Department of Fish and Wildlife has also confirmed TAHD in elk populations in both western and eastern Oregon.
State wildlife managers are asking for the public's help to monitor and prevent the spread of TAHD in several ways:
- Leave hooves: Scientists believe that treponeme bacteria may persist in moist soil and spread to new areas on the hooves of infected elk. For that reason, WDFW requires hunters to remove the hooves of any elk taken in affected areas and leave them onsite. During the 2018-19 hunting season, this rule applies to GMUs 407, 418, 437, 454, 501-578, 633, 636 and 642-699.
- Report elk: Hunters can help WDFW track TAHD by reporting observations of healthy or limping elk as well as dead elk with hoof deformities using the reporting tools on this page.
- Clean shoes and tires: Anyone who hikes or drives off-road in a known affected area can help minimize the risk of spreading the disease to new areas by removing all mud from their shoes or tires before leaving the area.
From 2009 through 2014, WDFW collected hooves and tissue from 43 elk and partnered with the USDA National Animal Disease Center and four other diagnostic laboratories to analyze them in an effort to find the cause of the disease. The samples were taken from elk in areas of southwest Washington known to be affected by the disease as well as those believed to be free of the disease.
By 2014, all five laboratories had identified treponeme bacteria in samples from diseased elk but not in those from healthy elk, providing evidence of the role of treponeme bacteria in causing the disease. Those findings were independently reviewed and accepted by a WDFW technical advisory group, composed of the State Veterinarian's office, state public health officials, university researchers and other specialists.
Since then, the department has continued to partner with leading experts to better understand this disease, and has initiated a variety of field studies to assess the distribution and prevalence of the disease, along with its effect on elk survival and productivity. WDFW is also working closely with Washington State University's College of Veterinary Medicine, which was designated in 2017 by the state Legislature as the state lead in assessing the causes and potential solutions for elk hoof disease.