University of Illinois at Urbana-Champaign
Researchers have developed a faster and more accurate way to test for
infection with Ophidiomyces ophiodiicola, a fungus that is killing snakes in
the Midwest and eastern United States. The test also allows scientists to
monitor the progression of the infection in living snakes.
The researchers reported on the test at the 2014 Mycological
Society of America Annual Meeting.
“We need people to know that they don’t have to anesthetize an animal
to collect a biopsy sample or, worse yet, euthanize snakes in order to test for
the infection,” said University of Illinois comparative biosciences department
professor Matthew Allender, an expert in snake fungal disease. “Now we can
identify the infections earlier, we can intervene earlier and we can
potentially increase our success of treatment or therapy.”
The new test uses quantitative polymerase chain reaction (qPCR), which
amplifies fungal DNA to identify the species present and measure the extent of
infection.
Researchers first took notice of Ophidiomyces in snakes in
the mid-2000s. Today the fungus threatens the last remaining eastern massasauga
rattlesnake population in Illinois and has been found to infect timber
rattlesnakes, mud snakes, rat snakes, garter snakes, milk snakes, water snakes
and racers in several states, Allender said.
“I’ve tested snakes from Illinois, Tennessee and Michigan, and we’ve
tested samples from snakes in New Jersey, Georgia and Virginia,” Allender said.
Snakes in Connecticut, Massachusetts, Minnesota, New Hampshire, New York, Ohio
and Wisconsin have also tested positive for the fungus.
Ophidiomyces consumes keratin, a key ingredient in snake
scales. It can cause scabs, nodules, abnormal molting, ulcers and other disfiguring
changes to snake skin. Mortality is 100 percent in Illinois massasauga
rattlesnakes found with outward signs of infection, Allender said. There are
only 100 to 150 massasaugas left in Illinois, he said, and about 15 percent of
those are infected with the disease.
Allender also is an affiliate of the Illinois Natural History Survey,
part of the Prairie Research Institute at the U. of I. He and his INHS
colleague, mycologist Andrew Miller, liken this emerging fungal disease in
snakes to white-nose syndrome, another fungal disease that has killed
millions of North American bats. Miller and graduate student Daniel Raudabaugh
recently published an analysis of Pseudogymnoascus destructans, the fungus
implicated in white-nosed syndrome, and are repeating the analysis on Ophidiomyces.
“The fungus killing these snakes is remarkably similar in its basic
biology to the fungus that has killed over 6 million bats,” Miller said. “It
occurs in the soil, seems to grow on a wide variety of substances, and
possesses many of the same enzymes that make the bat fungus so deadly.”
Other colleagues at the INHS, herpetologists Michael Dreslik and Chris
Phillips, have been studying eastern massasauga rattlesnakes in the wild for 15
years, and are working closely with Allender to characterize both biological
and health factors that lead to infection. The new qPCR test is integral to
this mission, Allender said. It also will help the team develop new therapies
to treat infections in snakes.
“This work is truly collaborative across disciplines, allowing the team
to make advances in studying this disease that haven’t been accomplished
anywhere else,” Allender said.
“Our qPCR is more than 1,000 times more sensitive than conventional
PCR,” Allender said. “We can know how many [fungal spores] are in a swab and
then we can start to treat the snake and we can watch to see if that number is
going down.”
The researchers also are hoping to find new disinfectants that will
kill the fungus so that researchers who are studying snakes in the wild will
not spread it to new locales on their equipment or shoes.
“Some of our preliminary studies show that the common disinfectants
that we use are not effective,” Allender said. “This fungus overcomes it.”
Source: University of Illinois at Urbana-Champaign