Understanding Drivers of Sarcoptic Mange in American Black Bears – Fellowship Training Grant

SUMMARY: Researchers will study genetic influences and skin microbiome (bacteria and fungi) in mange development in American black bears, a growing disease concern for this species.  

THE PROBLEM: Sarcoptic mange emerged in American black bears in the 1990s and is now endemic in some Northeastern states. Since 2018, this disease has become more common, and people have reported it in several new states. Sick bears develop itchy lesions and hair loss. In some bears, the disease is so severe they die. Not only is this an individual animal welfare issue, but at least two states have expressed concerns that the population of black bears may be decreasing in areas with severe mange. Researchers know little about the drivers influencing individual bear susceptibility and the emergence of mange in previously unaffected bear populations. With the increase in reported cases of mange, there is an urgent need to understand why previously unaffected bears are now developing severe disease.  

THE PROJECT: Researchers will conduct two studies to better understand why particular black bears develop severe mange disease, why others don’t, and how mange affects individual bear health. In the first study, researchers will see if there is a genetic reason for black bears to develop mange. The team will examine genes associated with the immune system to see if black bears have genetic changes that make them more vulnerable to disease.    

In the second study, researchers will see how mange changes the communities of bacteria and fungi (the microbiome) that live on bears' skin. This is important because drugs that treat mange do not address bacteria or fungi, which are often present and may cause additional diseases. Depending on the kind of bacteria or fungi present, this can be a contributing factor that could cause more severe disease.  

POTENTIAL IMPACT: These two studies will improve bear health by understanding what may predispose a bear to develop sarcoptic mange. Findings on bacteria and fungi that may drive disease will also help inform novel treatments to save individual and regional populations of American black bears.