Tag Archives: DISEASE

WDFW To Kill Elk To Prevent Hoof Rot Spread After Disease Found In Trout Lake Herd, First East Of Crest


For the first time, state wildlife managers have found elk on the east side of the Cascade Range infected with a crippling hoof disease that has spread to 11 counties in western Washington over the past decade.


Lab results from a deformed hoof and direct observations of elk walking with a profound limp in the Trout Lake Valley of Klickitat County provide clear evidence that the disease has spread to that area, said Eric Gardner, head of the Washington Department of Fish and Wildlife (WDFW) wildlife program.

“This is a huge concern for us and a lot of other people,” Gardner said. “This is a terrible disease and there’s no vaccine to prevent it and no proven options for treating free-ranging elk in the field.”

In response, state wildlife managers are preparing to euthanize any elk showing signs of the disease near the small town of Trout Lake, about 60 miles northeast of Vancouver. The goal is to stop it from spreading farther into eastern Washington, Gardner said.

“This is the first time the department has tried to stop the advance of the disease by removing affected elk,” said Kyle Garrison, WDFW hoof disease coordinator. “There’s no guarantee of success, but we believe a rapid response might contain this outbreak given the isolation of Trout Lake and the low prevalence of elk showing symptoms of the disease.”

He said the department plans to remove up to 20 symptomatic elk from the area in May. The Rocky Mountain Elk Foundation, which supports the proposed action, has pledged $2,000 to help defray the department’s costs.

Garrison and other WDFW wildlife managers will discuss the department’s plans at a public meeting from 6 to 8 p.m. Thursday, May 3, at the WDFW regional office at 5525 S. 11th St. in Ridgefield.

The first sign that the infectious disease had spread so far east came April 4, when a resident of Trout Lake sent the department a deformed hoof from an elk killed in a vehicle collision near his home, Garrison said.

On April 17, a WDFW staff team searched the area for other elk that might have been infected. They observed at least seven elk walking with a pronounced limp – a common symptom of the disease – and shot one limping animal to obtain hoof samples for testing.

Tests at Colorado State University’s Veterinary Diagnostic Laboratory and the USDA National Animal Disease Center confirmed both elk had hoof disease, Gardner said.

“We need to act quickly if we hope to get ahead of this situation,” Garrison said. “Elk in lowland areas begin to disperse into summer grazing areas by the end of May.”

WDFW staff met this week with local landowners to discuss the upcoming action and to gain permission to enter their property, Garrison said. The department plans to contract with USDA Wildlife Services to euthanize symptomatic elk, and Washington State University’s College of Veterinary Medicine will test tissue samples.

“The college is cooperating with Washington Department of Fish and Wildlife and other agencies in accordance with direction from the Washington Legislature to research elk hoof disease,” said Dean Bryan Slinker. WSU pathologists will conduct post-mortem examinations of the euthanized elk and will collect as many tissue samples as possible, he said.

For the past decade, WDFW has worked with scientists, veterinarians, outdoor organizations, tribal governments and others to diagnose and manage the disease.
Key findings include:

  • Wildlife managers believe elk carry the disease on their hooves and transport it to other areas. Once the disease becomes established in an elk population, it is extremely difficult to manage.
  • The disease appears to be highly infectious among elk, but there is no evidence that it affects humans. The disease can affect any hoof in any elk, young or old, male or female.
  • 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. 

For more information about treponeme-associated hoof disease in Washington state, see https://wdfw.wa.gov/conservation/health/hoof_disease/

IDFG Reports Results Of Elk Calf Mortality Study In Couer d’Alene, St. Joe Basins


By Laura Wolf, Wildlife Regional Biologist

The Panhandle region placed 172 GPS radio-collars on 6-month old elk calves in the Coeur d’Alene and St. Joe River drainages since 2015.  A couple reasons we collared so many elk was to determine survival rates and for those elk that didn’t make it, find out why they died.


The GPS collars have a signal that activates once the collar hasn’t moved for several hours, indicating a mortality.  Next, the collar sends an e-mail to biologists with the location of the collar.  It’s pretty amazing technology, something that wasn’t available just a few years ago, and it’s giving us new insight into what’s affecting the elk population.  We try to hike out to every dead elk within a day or two of receiving the mortality signal so we have the best chance of figuring out what happened.

It can be difficult to look at a partially consumed elk carcass and determine how the animal died.  The more of the elk that is there, the easier it is to figure out what happened.  We want to find out why it died, or in our language, determine cause-specific mortality.  That’s why we try to get to the elk as soon as possible.

Once we get to the location and find the elk, we take a crime scene approach.  We conduct a careful search around the carcass looking for predator tracks, hair, drag trails in the dirt or snow, broken branches that indicate a chase, and blood on vegetation or the ground.  Next, we perform a necropsy (basically an autopsy for an animal).  We skin the entire animal looking for teeth or claw punctures and bruising on the skin or muscles (which means that something injured it while it was still alive).  We look for broken bones, parasites, and abnormalities of the internal organs.  Lastly, we saw open a femur bone to examine bone marrow.  Bone marrow is normally hard and white and is the last fat reserve the body uses during starvation.  Soft and red bone marrow means the elk was in very poor condition when it died.

The two most common predators that kill older calves in the Panhandle are mountain lions and wolves, but their kill patterns are quite distinctive, hence the crime scene approach.  Lions tend to ambush and bite the neck or throat of their prey.  The attack site and the kill site are often close together.  Lions often drag their prey to a more hidden spot and will cache the animal by covering it with snow, leaves, or needles.  Lions have a habit of shearing hair, which looks like someone cut the hair with sharp scissors.   Lions often enter the chest cavity first and eat the internal organs.


Wolves, on the other hand, are not ambush hunters.  They typically chase their prey long distances, biting hindquarters, flanks, neck, and face.  Wolves will eat the animal where it died and often scatter the carcass throughout the site as each wolf takes its own piece to consume.  Wolves will often chew on all the bones.  The site of an animal killed by wolves is often a much messier scene than that of one killed by a mountain lion.  There’s often very little of the carcass remaining when we get there.


So, what have we learned?  In the normal to mild winters of 2015 and 2016, 80% of the elk calves survived from January to June; 14% were killed by mountain lions, 3% were killed by wolves, 1% died of disease, and 2% were unknown deaths.  A survival rate of 80% for 6 month old calves is very high.


In the colder, snowy winter of 2017, 50% of the elk calves survived.  Interestingly enough, the predation rates were similar to the milder winters; 16% were killed by mountain lions and 6% were killed by wolves.  Starvation (16%), heavy parasite loads (2%), and disease (2%) accounted for the difference in survival rates among the winters.  Calves were in worse body condition in 2017 as determined by bone marrow condition.  We could not determine cause of death in 8% of the cases.


What do these calf survival rates mean for the elk population?  We are working on some modeling now, incorporating other information like cow survival rates, calf:cow ratios that we get during our winter aerial surveys, and the percent of spikes in the harvest.  Once we get the results of the modeling , we’ll report to you on that.

Our jobs can certainly be gruesome at times, but it rewarding to determine what is happening with our elk populations so we can make informed management decisions.

OSU Studying Bighorns To Learn More About Risk From ‘Killer’ Bacteria


With their ability to climb steep rocky mountain areas, California bighorn sheep live in some of the most rugged environments Oregon has to offer.

No matter how high they go, the wild sheep can’t elude Mycoplasma ovipneumoniae – the bacteria now widely thought to be primarily responsible for fatal infectious pneumonia in bighorns. Respiratory disease has killed numerous wild sheep in Oregon and other Western states over the past few decades and is considered the largest risk to wild sheep populations, according to the Oregon Department of Fish and Wildlife.


Once a herd is infected, an all-age die-off can occur, and the disease remains chronic in the population.

Now, Oregon State University researchers are studying several aspects of the California bighorn sheep herd in the state – including movement, habitat use and survival – to gain insight into the animal’s risk for contracting the killer strain known as M. ovi (pronounced m-ovee). The disease spreads through contact between domestic sheep flocks and bighorn sheep, or from bighorn to bighorn.

Oregon is home to about 3,700 California bighorn sheep in 32 different herds in central and southeast Oregon. ODFW traditionally captures and relocates California bighorn sheep around the state each year to improve genetic diversity and restore this rare species to its historic range in Oregon. But these relocation efforts are on hold this year while wildlife managers learn more about M. ovi, partly through the work being done at OSU.

Often, the first contact with a particular strain of pneumonia kills bighorn of all ages, according to OSU wildlife biologist Clint Epps. Some adults survive, but then as the infection persists their lambs die every year. A bighorn herd might not recover for decades.

Wildlife managers strive to keep wild and domestic sheep and goats separate to avoid transmission of the disease.

“There is a high-stakes need to understand where the pathogen is likely to enter a bighorn population and where it’s likely move after that,” Epps said. “In the past few years, wildlife agencies in the West have made decisions to remove certain individual animals, or all individuals in the herd, to prevent the spread of disease.”

A die-off of the bighorn sheep herd in the Lower Owhyee River Canyon in 2015-16 raised concerns about how M. ovi is impacting Oregon’s wild sheep populations. Also, that year the Nevada Department of Wildlife made the difficult choice to euthanize an entire herd of sick bighorn sheep just south of Oregon’s border to stop the spread of M. ovi to neighboring populations.

In 2011, ODFW had to kill five of the 20 bighorn sheep reintroduced to the John Day Fossil Beds after they wandered into an area where they could have been exposed to a domestic sheep farm.

“There’s been a tremendous amount of effort to increase these bighorn populations, and our goal is to provide better information when they make those decisions,” Epps said.

ODFW wildlife biologists and veterinarians have sampled and collared more than 120 California bighorn sheep in the past two years. Recent samples from those captured bighorn sheep, some of which were tested at OSU’s Veterinary Diagnostic Laboratory, will provide extensive information on diseases and animal health, including determining whether the strain that eliminated the Nevada herd has spread to Oregon’s bighorn sheep.

Robert Spaan, an OSU doctoral student, travels to southeastern Oregon from April to August to study the California bighorn sheep herds, which each typically number between 30 and 150 individuals. He tracks the bighorn sheep that have been fitted with GPS collars by ODFW and records birth and death data.

“We’re able to respond to mortalities, and we are able to determine cause of death in most cases,” Spaan said. “We managed to detect a die-off of lambs in one population last year, the only one where we saw active M. ovi infection.”

Disease was one of the factors when bighorn sheep died off in Oregon in 1940s, along with unregulated hunting. But sport hunters have since been instrumental in restoring bighorn sheep in Oregon. Oregon Department of Fish and Wildlife’s annual auction and raffle of special bighorn sheep tags have generated thousands of dollars for their management and for research.

Among the funders of the study are the Oregon Department of Fish and Wildlife and the Oregon Foundation for North American Wild Sheep.