Granite Geek: Fungus killing porcupines reflects a bigger issue

Monitor staff
Published: 9/30/2019 6:11:29 PM

If Laurel and Hardy invented a woodlands creature, they’d make something like the porcupine.

Sure, porcupines have painful quills, but Laurel and Hardy took a lot of painful pratfalls. The thing is, those quills are such a great defense mechanism that the species hasn’t needed to evolve anything like brains, grace or speed.

The result is a true slapstick artist that blunders through the woods, poops on itself, and demonstrates a charming level of dim-witted clumsiness.

“They’re professional tree-climbers that stink at climbing trees! They fall out of trees all the time,” said David Needle, a veterinary pathologist and UNH professor, with an admiring twinge in his voice. Another point in their comic favor: They are, he says, the loudest eaters he’s ever heard.

“I like all wildlife, but you’ve really got to like porcupines,” Needle said.

Unfortunately, there is a less amusing reason for porcupines falling out of trees: A fungal disease discovered by a team of UNH researchers led by Needle using an innovative technique of molecular analysis developed at Cornell is spreading among the population.

Yes, I’m afraid we’ve shifted from movie’s greatest comedy duo to yet another sweeping environmental problem. It gets even more depressing, because porcupines aren’t alone in facing threats from fungus.

“Some of the biggest, most important pathogens of wildlife are fungi,” Needle said.

There’s white-nose syndrome, which has obliterated entire species of bats. There’s chytridiomycosis, which is devastating so many species of frogs and salamanders worldwide that it has been called an amphibian apocalypse. There’s the boringly-named snake fungal disease, which has just shown up in New England. There’s even a newly discovered fungus disease that attacks the shells of turtles.

Plants are victimized, too. Many of the diseases that are wiping out tree species, like Dutch elm disease and emerald ash borer, are caused by a fungus even though attention focuses on the beetles that bore into the tree, carrying the fungus past the bark.

People are not immune. The Centers for Disease Control has a large and growing website about fungal diseases in the U.S. and the problem is global. “There’s a pan-India outbreak” of one fungal disease, Needle said. “It’s because of alterations in climate, population, the way they use corticosteroids and anti-fungal medications – it’s across an entire subcontinent.”

In fact that newly uncovered porcupine fungus is “zoonotic,” the biologist term for a pathogen that can spread from animals to people. So don’t kiss your pet porcupine.

Fungi are one of five or six, depending on how you count them, life kingdoms, like animals and plants. They are multi-cellular creatures that, unlike bacteria, have a nucleus.

“They are generally non-pathogenic, just like most bacteria. ... They don’t make their own energy, like plants do, so they have to do it by eating things. And they have an incredible diversity,” Needle explained. “There are fungi that are extreme-ophiles that live in really weird places. They’ve even found fungi on the space station.”

Humans have lived with fungi our entire existence, often quite happily.

“They end up being important historically. They allow us to make bread and beer, they create penicillin, they’ve had a long history of being associated with our ability to break down chemicals and larger molecules, and be able to ingest them,” Needle said.

But fungi can turn on us. The question is why so many are doing it now. The answer, it seems, are the usual culprits: Climate change and globalization.

Much of the world is getting warmer and wetter, which most fungus species like. And we’re flying and driving and sailing all over the globe, carrying fungus among us (you know I had to write that at least once), increasing the possibility that they’ll find a new host to infect or a new environment to thrive in.

Needle says fungus diseases have historically received less attention than bacterial or viral diseases for a number of reasons. They tend to spread more slowly, so there’s less fear about pandemics – although they also tend to be harder to get rid of. And they’re tough to analyze.

“Bacteria are really easy to manipulate in the lab; quicker generation time, it’s easy to change their genetics, knock out a gene and study the result. That’s really hard in a fungus, which makes it harder to study,” he said.

And other pathogens get better press. “I love doing emerging disease investigations, and a virus is way sexier! It’s a tiny little thing, have to get an electron microscope to see it,” Needle said.

As for our porcupine disease, it was found by analyzing 44 porcupines taken to wildlife rehabilitators along coastal areas of New England. On a dozen of the what appeared to be mange were actually a disease caused by a fungus found in cats and dogs known as Trichophyton mentagrophytes/Arthroderma benhamiae. (Most fungi don’t have a common name so Latin tongue-twisters are the norm.)

Interestingly, UNH pathologists collaborated with Dr. Laura Goodman and her team at the Cornell Animal Health Diagnostic Center, who had developed new molecular techniques for this set of cases that allowed scientists them to confirm that older cases of porcupines with skin disease were infected by the same pathogen. Needle says this is a big step toward studying and understanding fungal diseases because it provides better methods to track its spread and evolution.

“She is like a super awesome wizard,” Needle said of Goodman and her discovery. “I think probably the most lasting academic impact will be more about those techniques.”

Long term, Needle says our porcupines aren’t going to be quickly wiped out like ash trees – fortunately, no beetles are flying from animal to animal, spreading the fungus. But this is likely to be a stress on their Northeast population that will affect them as well as other species including fisher, the one predator that has figured out how to kill porcupines without getting stabbed.

“Porcupines play a really cool role in part of the wild lands in large parts of North America,” Needle said. “We wouldn’t want to lose them.”




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