Tag Archives: Fungal

Snake fungal disease could be a global threat, much bigger than we thought

Less than a year after a series of studies brought snake fungal disease into the spotlight, researchers believe the problem might be much bigger than anticipated.

Eastern racer (Coluber constrictor) showing signs of fungal skin infection. Obvious external abnormalities are an opaque infected eye, roughened crusty scales on the chin, and several discolored roughened scales on the side of neck. Credits: USGS National Wildlife Health Center/D.E. Green.

In June, scientists wrote about a dreadful fungal disease ravaging rattlesnakes in North America. Not long after that, similar findings were also reported in Europe. Now, a new study shows that the disease affects snakes regardless of their ancestry, physical characteristics, or habitats. This could mean that it’s much more widespread than previously thought, potentially affecting snakes all around the world, as it has already been documented in 23 wild species in the United States (including rat snakes, milk snakes, gartersnakes, and viperids) and three species in Europe.

“This really is the worst-case scenario,” said Frank Burbrink, an associate curator in the Museum’s Department of Herpetology and the lead author of the publication. “Our study suggests that first responders shouldn’t just be looking for certain types of snakes that have this disease, but at the whole community. All snakes could become infected, or already are infected.”

The main culprit behind the disease is a pathogen called Ophidiomyces ophiodiicola, which causes skin lesions, scabs, and crusty scales and can cause fatal infections in some cases. However, researchers aren’t sure if the pathogen alone is to blame, or if other environmental factors or pathogens also play a part.

Snakes aren’t the only ones to fall victim to fungal diseases. In recent years, similar issues have wreaked havoc on populations of frogsbats, and salamanders — snakes are only the latest

“Some of the most devastating wildlife diseases ever documented, such as white-nose syndrome in bats and chytridiomycosis in amphibians, are caused by fungal pathogens,” said Jeffrey Lorch, a microbiologist with the U.S. Geological Survey (USGS) National Wildlife Health Center. “These diseases have had such great impacts because they affect multiple species, and it now looks like the same is true of snake fungal disease.”

However, with snakes being hidden away for a few months a year and highly reclusive during the rest, studying them isn’t easy, and so biologists aren’t really sure how bad things really are. Prevention is better than treatment, but that may no longer be an option.

Journal Reference: “Host susceptibility to snake fungal disease is highly dispersed across phylogenetic and functional trait space” DOI: 10.1126/sciadv.1701387 ,


Snake fungal disease observed in Europe for the first time

Bad news for European snakes — the dreaded fungal disease already reported in the US seems to have spread to Europe as well.

Grass snake (Natrix natrix) with skin lesions due to snake fungal disease. Image credits: Zoological Society of London.

Just a few days ago we were telling you how fungal diseases — already so menacing for frogsbats, and salamander — are starting to threaten snakes as well. At this point, it’s unclear if a single pathogen is responsible or if it is a series of ailments rather than one, but the most likely culprit seems to be a pathogen called Ophidiomyces ophiodiicola, which causes skin lesions, scabs, and crusty scales and can cause fatal infections in some cases.

So far, over 30 species have been found suffering from the diseases in the US, with some species being more vulnerable than others; specifically, rattlesnakes have been found to be highly at risk. Humans, pets, and livestock are not at risk to the disease. Ophidiomyces ophiodiicola is only known to infect snakes. Now, researchers have found evidence of snake fungal disease (SFD) in Europe as well.

After analyzing samples gathered from wild snakes (the disease was already known in some zoos) from 2010 to 2016 in the United Kingdom and the Czech Republic, researchers have now definitely confirmed the existence of the disease on the Old Continent. Lead author and wildlife veterinarian Dr. Lydia Franklinos said:

“Our team at ZSL found evidence of SFD in grass snakes (Natrix natrix) from the UK and a single dice snake (Natrix tessellata) from the Czech Republic. The analysis found that the fungus strains from Europe are different to those previously identified in North America – suggesting that rather than being introduced across the Atlantic, or vice versa, the disease could have been present below the radar in European snakes for some time.

Grass snake skin shed with lesions positive for Ophidiomyces ophiodiicola. Image credits: Zoological Society of London.

Detailing their work in an open-access paper published in Scientific Reports, they’ve screened 33 carcasses and 303 molted skins from wild snakes, finding the fungus in 26 (8.6%) specimens across the period of collection. In most cases lesions were mild, but in some cases, researchers believe they contributed or were even decisive for fatality. It’s hard to estimate just how much damage the diseases is causing, and scientists call for more studies to paint a clearer picture. The reclusive nature of snakes certainly isn’t helping in this case.

“Of all terrestrial vertebrate wildlife, we probably know least about health conditions that affect reptiles such as snakes, so this study represents an important milestone and one that will hopefully encourage greater focus in understanding the threats facing these animals,” Franklinos adds.

Fungal pathogens are emerging worldwide at an alarming rate, and kind of snuck up on us. It’s important to understand just how much it spread across the world, and how it affects organisms different based on their environment. This might be the first step towards starting to fight it. Dr. Jeffrey Lorch, a microbiologist with the USGS National Wildlife Health Center and the study’s co-author, said:

“The fungus that causes SFD is already known to occur across the eastern half of the U.S. and infect over 20 species of snakes. Comparing how SFD affects wild snakes on different continents may help us pinpoint the factors causing the disease to emerge and help managers identify mitigation strategies.”

You might think that snakes aren’t that important, or that this is a natural thing and we should just let it follow its course. Snakes aren’t the most popular animals out there either, which likely contributes to the big gaps we have in our understanding of them. But like them or not, snakes play a vital role in ecosystems. Most snakes are middle-order predators, which means they eat some animals and are in turn eaten by others, filling a very important niche.

It’s not clear why this disease is emerging now, either. It could be a foreign, introduced pathogen, or it could be that various species across the planet are developing it independently. That remains to be established by future research. There is a good chance that environmental changes have rendered the snakes unable to defend themselves against the pathogen, or that at least, the changes have weakened them.

Several countries are already working on ways to improve reporting on such matters. In the UK, you can check out the Garden Wildlife Health Project for instance. The full paper is here — open access and published by the Institute of Zoology.