An emerging disease that was believed to only cause hoof deformation in elk appears to trigger molecular changes throughout the entire animal system.
This is the conclusion of an epigenetic study by experts at Washington State University (WSU), who set out to gain a better understanding of elk treponeme-associated hoof disease.
In a previous study from WSU, researchers discovered that healthy elk can contract the disease by simply walking on soil contaminated by infected hooves.
The experts described the disease as “devastatingly painful,” noting that it often leads to death.
“Affected elk suffer with deformed hooves, lameness, and increasingly poor health as a result of the infection,” said the report.
“The disease is spreading unabated and has been found in Washington, Idaho, Oregon, and California.”
The results of the latest study indicate that the molecular changes caused by hoof disease might not be limited to where the infection is visible, but could potentially be affecting the entire physiology of the elk.
According to the researchers, the illness severely impairs the elk’s ability to find food and escape predators.
The research suggests that the disease-induced changes may be heritable, but it is not yet clear whether this means subsequent generations of elk may be more prone to catching the disease.
“It’s not just the absence or presence of the infection. It’s affecting the animal’s entire physiology, all the cells,” said study senior author Michael Skinner, a WSU biologist. “It shows that there’s a molecular impact by the presence of the disease organisms.”
Epigenetics refers to stable molecular processes that influence gene behavior, independently of the DNA sequence.
These changes in an organism’s epigenetics can be brought about by various factors such as nutrition or the environment. The current study suggests that infectious diseases can also play a part.
The research team analyzed cells from the leg tendons of 55 Roosevelt and Rocky Mountain elk, both infected and uninfected.
These specimens were provided by hunters and procured by wildlife agencies across five states: Washington, Oregon, California, Idaho, and South Dakota.
Interestingly, the findings reveal epigenetic changes associated exclusively with the disease in the infected elk.
Considering that the tendon cells were located away from the hoof infection, this suggests that the changes induced by the treponeme-associated hoof disease could be systemic.
According to Margaret Wild, this research is only the tip of the iceberg.
“We’re building foundational knowledge to understand this disease,” said Wild. “By doing this epigenetic study, we can see apparent systemic impacts from the infection, even though we don’t see those pathological changes when we look at the elk.”
The disease’s name originates from the treponeme bacteria. However, researchers now theorize that it might be caused by multiple bacterial strains.
Wild and her team are currently undertaking studies in captive elk to identify the transmission mode of the disease. This research could also shine a light on factors like diet that may alter the animals’ vulnerability to the infection.
While elk remain the only wild species detected with the disease, WSU researchers are exploring possible connections to bovine digital dermatitis found in cattle.
There’s also an ongoing effort using computer modeling to identify environmental factors, such as soil type, moisture, and geography, which might determine where elks are more susceptible.
“This is a brand-new emerging disease that hardly anything is known about,” Wild said. “We are taking a multi-pronged approach and conducting a broad range of exploratory studies.”
“Our goal is to do as much research as we can to learn about all the impacts this disease is having on individuals and elk populations to help wildlife managers address the disease.”
The study is published in the journal Scientific Reports.
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