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article imageA mysterious fungus is killing snakes in the Eastern U.S.

By Megan Hamilton     Jul 21, 2015 in Environment
It started in Florida with the pygmy rattlesnakes, killing 42 of them. Then, another 59 wound up dead.
When it happened in the earlier part of this century, mystified scientists couldn't identify the culprit.
Researchers now think that a deadly fungal infection was the culprit, and the infection is spreading among the snakes of the eastern U.S., Conservation Magazine reports.
Known as "snake fungal disease," or SFD, it has now been identified in at least 15 states, and it's a nasty disease. It appeared up in Illinois in 2008 in a species of rattlesnake called the eastern massasauga, causing severe skin lesions and swelling, and eventually creeping into the snakes' muscles and bones. It also showed up in 2006 in a population of timber rattlesnakes in New Hampshire, and these snakes showed the same symptoms. There had been at least 40 snakes in that population before the outbreak, but only 19 survived.
A northern water snake (Nerodia sipedon)  which was captured in 2009 from an island in western Lake ...
A northern water snake (Nerodia sipedon), which was captured in 2009 from an island in western Lake Erie, Ohio. The snake has crusty and thickened scales over raised blisters, a sign of snake fungal disease.
D. E. Green/USGS National Wildlife Health Center
SFD affects other species of snakes in different ways. Garter snakes, ribbon snakes, and rat snakes have also died from this disease, but the infection works differently in these nonvenomous creatures. They wind up with pneumonia and eye infections, Conservation Magazine reports. At least one garter snake has suffered from a liver infection.
SFD is mysterious; little is known about Ophidiomyces ophiodiicola, or Oo, the fungus that causes it.
University of Illinois researcher Matthew C. Allender and his colleagues wanted to gain a better understanding of how this snake-killing fungus works. Their findings were published last week in the journal Fungal Ecology.
What they found is that Oo eats keratin, which is what human fingernails, rhino horns, and snake scales are comprised of. Most tragically, researchers have never found a snake that survived this infection. "Mortality appears to be 100 percent," Allender wrote.
The fungus thrives perfectly well in soil, where it consumes dead animals and plants, and the researchers don't know why it's suddenly set its sights on living snakes. They think the fungus is acting in an opportunistic fashion. When snakes emerge after hibernating their immune systems aren't up to snuff, and takes a while to get revved up. Of course, that's a perfect time for the fungus to move in and start partying.
Conservationists are comparing the sudden and mysterious increase in this disease to white-nose syndrome in bats. SFD cropped up occasionally in the past, but it began showing up more frequently in 2006, Smithsonian.com reports.
Conservationists compare its mysterious, sudden increase in appearance to white-nose syndrome in bats. While SFD cropped up occasionally in the past, it started showing up more frequently in 2006.
Diana Yates, the Life Sciences editor of the news bureau at the University of Illinois, detailed the similarities.
"Both the bat and snake fungi can survive on most carbon and nitrogen sources found in soils," Illinois doctoral student Daniel Raudabaugh said. He analyzed specimens from both diseases in Miller's lab.
"Like the bat fungus, the snake fungus is tolerant of elevated sulfur compounds," Raudabaugh said. "It grows on dead fish. It grows on dead mushrooms — most complex carbon sources. It can utilize nitrate, but its growth is not nearly as robust (as the bat fungus) on nitrate."
What worries the researchers now, isn't that the disease is here, but that it's prevalence is being underestimated, NatureWorld News reports. Anyone who spends time out in the wilderness likely knows that snakes are a challenge to find. So, the question is, if snakes can't be surveyed, how will scientists know if there is an epidemic until it's too late? We may well have to wait and see.
On one level herpetologists are worried about the effects of the infection on individuals, but the bigger issue is how much of a role the fungus may play in population declines. Plus, as global temperatures increase, snakes will likely become even more susceptible to infection by Oo, especially in areas of the world where winters will turn milder. The reason for this is that the fungus's growth seems to slow down as its environment begins to cool towards freezing.
While naysayers who don't like snakes may think their disappearance is a blessing, they should consider this:
Rodents make up a huge part of the diet for many species of snakes, and without snakes to control them, we'd be in a mess of plague proportions.
Rattlesnakes consume around 40 percent of their own body weight every year, The Internet Center for Wildlife Damage Management reports. Often, the prey is killed but not eaten by the rattler, either because the prey is too big or can't be tracked after being attacked. One male rattler captured out in the field had eaten as much as 123 percent of his body weight. Young rattlers often die due to not enough food. Rattlers that have been raised domestically often only survive if they are fed once per year, but in the field, wild snakes usually feed more than once, but this depends on the size of the prey consumed. Sometimes a snake will kill several different species of prey, one right after another.
Snakes are beautiful and fascinating creatures and they have helped to transform this planet into the wonderful home we have now. May they slither alongside us forever.
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