Florida panthers deemed unaffected by emerging fatal genetic condition

The findings abate concerns that this fatal disease, known as chronic wasting disease, is threatening the species.

The study, published this week in the Journal of Wildlife Diseases, states that Florida panthers are not at increased risk for contracting the disease. Chronic wasting disease is caused by a misfolded protein known as a prion and can be transmitted through predator and prey interaction, such as a panther eating a deer that has the disease.

UCF biologists were collaborating with partners at other universities and the Florida Fish and Wildlife Conservation Commission (FWC) to monitor genetic mutations as part of a greater conservation effort, when they examined this specific disease after chronic wasting disease was detected in Florida white-tailed deer in 2023.

Pumas -- the common name for panthers in western North America -- were introduced to Florida from Texas in the 1990s to help restore the dwindling panther population, says Bob Fitak, UCF assistant professor of biology and study co-author.

"About 30 years ago, there were only 20 or 30 Florida panthers left, and they [became] really inbred," Fitak says. "So, they brought in panthers from Texas to help supplement this population, to help restore or recover the population. It's been a really successful program. We try to understand why that was successful and what we need to watch out for in the future. We call this genetic rescue or genetic restoration."

According to the FWC, there are approximately 120-230 adult panthers in the population. While the introduction of similar species means greater genetic diversity and new concerns, the study provides further evidence that this is a net positive, Fitak says.

"We're not changing the Florida panthers in any way to make them more or less susceptible to diseases," he says. "It's kind of confirmation that we don't expect any unusual circumstances when it comes to their susceptibility here in Florida that would be any different than another part of the country."

Chronic wasting disease has spread through North America throughout deer and elk populations, and conservationists are concerned that it may infect predators who consume deer or elk as prey. Any organism that eats the deer may be at risk, so monitoring these populations is important, Fitak says.

"We sequenced the DNA of this gene in a bunch of Florida panthers, and we were able to show that Florida panthers are not any more or less susceptible than other populations of pumas in North America," he says. "This is a really good thing. We know in the rest of the country pumas can eat infected deer and not get sick. So, we think that the same pattern is going to happen here in Florida, and we don't see any increased risk of Florida panthers to this disease."

Fitak credits the FWC and the study's lead author, Elizabeth Sharkey, a student who participated in UCF's 2022 Research Experience for Undergraduates program under his mentorship, for significant contributions to the research.

"We started with 37 Florida panther samples and four polymorphic sites, but as we began to incorporate more samples from Central and South America, we found more and more diversity," says Sharkey, who is now a graduate student in biological anthropology at Washington University in St. Louis. "I had the opportunity to conduct a lot of lab work to analyze the prion allele, and after my program ended, I continued to work with the team to write our publication."

Her early exposure to research through the REU program yielded great results.

"Our research uncovered a new Central American prion allele that was likely introduced into the Florida panther population prior to the famous genetic rescue in 1995 when five Texas pumas were brought to Florida," Sharkey says. "When this research first began, prion disease had not yet made its way to Florida, but on June 30, 2023, the FWC identified the first case of a prion-disease-positive deer in Florida."

She continued to pursue the research and collaborate with Fitak and others to analyze the DNA samples and ultimately determine that Florida panthers are not especially susceptible.

"It was a huge relief that our research provided evidence that the panthers will be OK and are not more susceptible because of introduced alleles," Sharkey says. "Luckily for the Florida panthers, the new allele does not appear to impact susceptibility to prion disease, and it is rare or nonexistent in the current Florida population."

Fitak says he's encouraged by the findings reported in the study, and that he hopes the Florida panther population remains robust if chronic wasting disease becomes prevalent in Florida's deer herd.

"Florida panthers are probably going to be okay if this disease spreads in Florida, which hopefully it doesn't," he says. "The FWC in Florida is doing a great job of trying to mitigate the spread and monitor it."