A team of researchers with the University of Kentucky is contributing to a nationwide effort to understand a fungal disease impacting native snake species.
Ophidiomycosis, or snake fungal disease (SFD), was first documented in the U.S. in 1945 and has been on the rise in the eastern part of the country since 2006.
Steven Price, interim chair of the department of forestry and natural resources and an ecology professor at the University of Kentucky, has been studying the disease’s impact on snakes for more than five years. Since January, he’s led a team along research sites throughout the state, collecting valuable data on local snake population health.
One of those team members is Eleanor Lane, a PhD candidate overseeing much of the research.
“We know that there are a variety of strains, with different effects ranging from incredibly mild with just lesions, to one that’s colloquially known as the ‘bone melting’ strain, which is a very fun and scary name,” Lane explained.
While that particular strain hasn’t been detected in Kentucky, local snake populations have seen the impacts of lesser strains. Snakes have been found with large lesions, growths beneath their skin, and severe swelling on the head and mouth, which can impact the snake’s ability to eat and ultimately survive.
“In Kentucky, there’s been two strains identified, both of which seem to be fairly mild. But it’s really hard to know if this is impacting snake populations because it’s hard to collect good population data on snakes,” Price said.
He said that when compared to population data on many other species, collecting information on snakes can be similar to finding a needle in a haystack.
“When you think about bats and White Nose Syndrome, you can enter a cave and you can see those carcasses right? You can count the number that are gone,” Price said. “There’s a disease with amphibians called chytridiomycosis where you can see dead animals. With snakes, if they die somewhere out in the field or underground or somewhere, the chances of finding those are slim to none.”
To help with that population-level data and increase their odds of encountering snakes at research sites, the team has strategically placed roughly 800 large pieces of tin or plywood at six locations across the state.
At the data site, Price, Lane, and research assistant Cayce Jones collect data on cloud cover, temperature above and below the board, wind speed, barometric pressure, and site location.
At the team’s site farthest to the west, in a Barren County forest, they discovered their first recorded prairie kingsnake. The researchers processed the juvenile snake, taking down vital signs like length, weight, sex, and noting a small clinical sign of SFD before outfitting it with a pit tag, a small microchip similar to those used in dogs or cats.
“Yeah, so we would consider this a really mild case of snake fungal disease. Whereas, you know, these snakes, probably through shed or through basking or things like that, they can probably fight off the infection. But in some cases it could progress and get worse,” Price said.
A swab of the clinical sign was taken, as well as a soil sample where the snake was found. The team hopes to use that data to learn more about how the disease is transmitted - whether through the environment, through contact with other infected snakes, or a combination of both.
“Part of the question we’re trying to answer is, how can the snakes spread the disease from one site to the next? How much time do snakes spend under certain boards? Who all uses those boards? Questions along those lines,” Price said.
After collecting the necessary data, the snake is released unharmed at its original location.
Beneath another board, the team discovered a more serious case of SFD. A small ringneck snake, roughly the size of a pencil, was found with a large wound that had been infected by the fungus, preventing the wound from healing and causing further complications. The infection spread, leading to large nodules beneath the skin.
“We think if a snake’s heavily infected, then goes into hibernation, their body is constantly cool, good growing conditions for the fungus, it’s not great for the snake at that point. So, in this case, I would say this snake probably has a greatly reduced chance of surviving the winter if it doesn’t clear this infection before then,” Price said.
He explained that when snakes are infected, their primary method of clearing that infection is through basking. While attempting to raise their body temperature high enough to ward off the fungus, they place themselves at higher risk of being eaten by predators like birds, raccoons, or opossums. Those species are not susceptible to the infection.
After collecting vital signs and infection samples, the snake was released without further harm.
Beneath other boards, the research team found several small ringneck snakes and one large gray ratsnake, none of which showed clinical signs of SFD.
Beneath a final board, the team discovered two venomous eastern copperheads, a target species for their research. Some studies suggest that pit vipers are especially susceptible to SFD, though there are more precautions taken by the team when handling venomous snakes.
“So we don’t free-handle venomous snakes, they’ll go in these clear plastic tubes so their head is not near any of our appendages, and that way we can safely work them up, it keeps them a little bit more secure as well,” Lane said.
The team uses long snake hooks and tongs to place the snakes in buckets. From there, the snake's heads are coaxed into clear tubes to examine them for clinical signs of infection, collect research data, and check for pit tags. One of the copperheads is a recapture - a female that had been pregnant less than two weeks ago.
“She’s very very pretty, since we saw her less than three weeks ago there’s no need to do a full work up on her. She was very strikey and mad last time we saw her, but she’s pretty chill now,” Lane said.
Both copperheads were clear of clinical signs and released unharmed in their shared hiding spot beneath the board.
Price said the research conducted by his team is vital for monitoring local snake population health, but also contributes to a larger mission of tracking disease transmission on the human level. He said the studies conducted by his team at the University of Kentucky, as well as researchers at Virginia Tech, and the U.S. Geological Survey highlight the intersection of public health and ecological health.
