There was something wrong with the juvenile broad-banded water snake researchers found in March 2015 in the Lake Martin area of Louisiana. Despite warm temperatures outside, the snake was coiled up and basking in the sun on the trail.
“It didn’t do anything. I picked it up and it couldn’t even right itself,” said Brad “Bones” Glorioso, ecologist with the U.S. Geological Survey, Wetland and Aquatic Research Center in Lafayette.
Glorioso took the young snake back to the lab where its health continued to decline. Four days later, the scientists saw that the snake was in worse shape and had to euthanize the animal.
The snake became the first documented case in Louisiana of a disease that has been found in the Midwest and East Coast called snake fungal disease.
This discovery was recently published in the “Southeastern Naturalist” and adds Louisiana to the growing list of states where this disease has been found.
Little is known about what impact the disease has on different snake species, what implications it holds for population levels or even how widespread the disease is. Some studies have scientists concerned.
According to the Geological Survey, snakes in New Hampshire that showed signs of having the disease were linked with a 50 percent decline of timber rattlesnakes between 2006 and 2007. In the Midwest, it’s estimated that up to 90 percent of fungus-infected rattlesnakes, called massasauga, die as a result of the disease. Other species have had a much lower mortality rate.
“We don’t know if some species are able to clear an infection or survive a mild infection,” Glorioso said. “There’s so many questions out there and we’re just scratching the surface.”
The snake populations, in some cases, already are stressed because of habitat loss or small populations. There has been an increase in research looking for answers, but questions remain, such as where the disease came from, how does it spread, how has it survived over time or why has it had an impact only since 2000.
“A snake that’s sick is going to stop feeding and start to bask (in the sun),” Glorioso said.
As a result, they lose body mass and their extra exposure during basking means they’re more vulnerable to predators, he said.
The confirmation of the disease in the state has prompted Glorioso and others to start collecting, recording and then recapturing snakes in a seven-acre area on Palmetto Island State Park.
“That’s very hard to do with snakes,” he said.
When a snake is captured, the researchers record any abnormalities like scabs, crusty scales, cloudiness of the eyes or nodules under the skin. Researchers then swab areas of the snakes that appear diseased, the snakes are marked, a microchip is installed and then the animal is released. If they are recaptured, their weight and other characteristics can be recorded again to see if there’s any change and if there are any problems in those that test positive for the fungus.
Glorioso said researchers found a ribbon snake with the fungus and, when it was recaptured weeks later, it was found to have lost significant weight. The same snake was seen weeks later and it was dead.
The swabs only test for the fungus. In order to confirm that a snake has snake fungal disease, skin samples need to be sent into a laboratory, a process that is more invasive than just testing for the fungus.
The catch-release project started in August and likely will run for a couple years as researchers gather more information.
“I want to know how it affects population,” Glorioso said. “In the end, what we’d like to do is model survival by using whether or not the snake tested positive for the fungus that causes snake fungal disease.”
While research on the disease is ramping up, Glorioso acknowledges that some people won’t find the prospect of snakes dying at all disturbing.
“For people like myself, we know the important role snakes play,” Glorioso said.
Not only are they efficient rodent controls, but they also provide food for other animals that people do enjoy, such as wading birds or herons.
“It comes down to two words: Biodiversity matters,” he said.