DNR seeks data about diseased snakes
Scabby blisters attack vital part of food chain
Conservation biologists from the state Department of Natural Resources are scouring the ground turning over hundreds of rocks and logs in search of snakes with a fungal disease.
And don’t dismiss that as inconsequential.
Snakes likely would lose a popularity contest, but Rori Paloski, a DNR conservation biologist, explained that snakes are some of the most important creatures in our ecosystem. As both predator and prey, they impart balance to the food chain and provide environmentally friendly pest control.
As predator, they help control rodent populations that can cause extensive damage to agricultural crops and gardens and spread diseases that affect humans — such as Lyme disease.
As prey, they feed hawks, eagles, foxes, weasels and even bigger snakes.
“Like all animals, like them or despise them, they are part of our native biodiversity, and we need to keep this intact. No one knows what will happen if we start losing species, nor do we want to find out,” Paloski added.
A declining snake population could have important implications for human health as well.
“By removing snakes, we might be actually increasing the exposure of people and domestic animals to things that affect them,” said Matt Allender, a veterinarian, epidemiologist and director of the Wildlife Epidemiology Lab within the College of Veterinary Medicine at the University of Illinois. “We want to maintain the diversity of the planet because we know diversity helps to improve the overall health of all species, including people.”
Researchers are specifically looking for snakes affected with snake fungal disease, which is caused by the Ophidiomyces ophiodiicola fungus.
The first documented case of snake fungal disease in Wisconsin was in 2011, but Paloski said museum records lead the DNR to believe that the disease has been in Wisconsin since the 1980s and 1990s.
Paloski and Rich Staffen, another DNR conservation biologist, said it’s likely that the fungus is a native species and has always been present in the environment at low levels, but different factors are responsible for it suddenly becoming more of a problem.
“These factors are still being investigated,” said Jeff Lorch, a microbiologist based in Madison who performs wildlife disease diagnostics and research for the U.S. Geological Survey. “It’s possible that climate is playing a role in this. Snakes are cold-blooded so they depend on the environmental temperature for things like activating their immune system.”
Lorch also explained that temperature plays a role in how long snakes need to hibernate. It may appear that climate change makes spring comes earlier, but cool, wet springs can force snakes to hibernate longer and stay in conditions conducive to infection progression.
Allender said it’s become clearer that there are differences in symptom severity between snake species, and those differences may stem from genetics, habitat, nutrition or climate.
Signs and symptoms
The disease already affects 11 of Wisconsin’s 21 native species. When the fungus invades the snake’s skin, the snake will try to fight off the impending infection. This causes inflammation that results in lumps and lesions along the snake’s face, neck and body. In some instances, skin blisters or scabby areas or white opaque cloudiness of the eyes may also indicate the disease.
“Worst case scenario is that it causes inflammation of their mouth tissue, and they can’t shut their mouths. Then the snakes aren’t able to eat and drink, so eventually they starve to death or die of dehydration,” Paloski said. “A few snakes have looked so bad that they had to be euthanized.”
In an effort to rid themselves of the fungus, Lorch said infected snakes will shed their skin twice as often as healthy snakes. To achieve this increased shedding rate, snakes will bask in the sun more often to speed up the process. Unfortunately, while they’re trying to bask and self-heal, they’re also more likely to become a larger animal’s lunch.
The DNR is looking for help in identifying areas where snake fungal infection is found.
“We have do not have the staff or the resources to survey the entire state,” Staffen said. “Therefore, it is imperative we get help from citizen scientists who are interested in snake conservation, or nature in general, to help us track reports of this disease throughout the entire state.”
“Snakes are not everyone’s favorite animal,” Paloski said. “But I am always amazed at how many herpenthusiasts, and in particular, snake “people” there are. They are very passionate about finding and protecting snakes, and for good reason.”
The DNR encourages the public to send pictures of any odd-looking snakes to DNRherptiles@wi.gov. In addition to the photos, the agency asks for observers to include when and where they saw the snake, the species (if known) and any symptoms.