Number 10916 didn’t look much different from any other Little Brown bat, but wildlife researcher Sybill Amelon with the U.S. Forest Service knew that it, along with 19 others, would serve a great purpose. All of these bats had a bright white, fuzzy fungus growing on their wings and on the tips of their muzzles.
This fungus, Pseudogymnoascus destructans, causes a disease commonly referred to as White-nose Syndrome, which has killed more than 5.5 million bats in North America in the past decade, according to the U.S. Fish and Wildlife Service.
The fungal disease was first discovered in eastern New York in 2007 and continues to move west. It is not exactly known neither how the disease came to the U.S. nor how bats contract the disease, but now, the ability to treat it might finally be possible.
In the winter of 2013-2014, the 20 bats were brought back to the lab by Amelon and separated into two groups of 10 to test a potential treatment. One group was given a treatment while the other was not. As the winter of 2013-2014 came to a close, six of the 10 treated bats had survived.
This potential treatment - produced by a soil bacteria found ubiquitously in North America and many other countries– could be a key to stopping a killer disease.
During late March in 2016, Amelon gave a presentation to the MU Zoo club on White-nose Syndrome and how it has affected different bats across the state. Amelon brought several bats, including number 10916. The bat was eventually given a new number, 116, due to it successfully surviving the disease. Amelon held the bat gently in her hand as it squirmed and chirped in her hand for a few moments. Once the bat began to calm down, she carefully opened up one of its wings to show holes that had been created by P. destructans.
“This happens to be one of the best-looking bats out of the bunch that survived,” Amelon says. “Some of the other bats suffered deformities including damage to ears, wings, and other parts of their bodies. When I take one to a presentation, it is likely this little guy, because he cannot be released due to the holes in his wings. So now, he is a WNS educational bat, and he has been very cooperative so far.”
Pseudogymnoascus destructans causes a bat to act abnormally during the winter when it is supposed to be hibernating. Side effects include bats hibernating closer to the entrance of various sites and flying during the daytime to try and catch food.
“The disease disrupts the bats’ homeostasis,” Amelon says. “We still are not certain what causes the bats to act this way. Once the later stages of disease begin, the fungus can be seen growing on any part of their body not covered by fur.”
The fungus eventually spreads across the wings and nose of the bats. It causes holes to form in the wings that prevent the bat from flying and eventually causes them to die.
Researchers discovered that the fungus spreads through contact with and distribution of its spores. Amelon explained that when a select few bats living in a site have this disease, it could take up to three years to wipe out a site’s population, depending on the species. In some species mortality exceeds 90 percent.
“Even though there are some bats that will live and rid the disease when the weather gets warmer, the population of a site will usually continue to decrease as time progresses,” Amelon says.
All hibernating bats are likely to be exposed to the disease, especially as it continues to move farther west in the U.S., but some are more susceptible to it than others. Shelly Colatskie is an assistant cave ecologist with the Missouri Department of Conservation. Since 2010, Colatskie has teamed up with Amelon to survey various sites across the state.
Little Brown bats (Myotis lucifugus), Northern Long-eared bats (Myotis septentrionalis) and tri-colored bats (Perimyotis subflavus) seem to be the most vulnerable.
“Each year it is getting more and more difficult to find these bats because of White-nose Syndrome,” Colatskie says. “For example, it is getting more difficult to find the little brown bat each year that we survey.”
On the other hand, some bat species such as the Big brown bat have seen lower mortality rates with White-nose Syndrome. “We are not sure why certain species seem to be able to fight off the disease better than others.” Amelon says. “But as an overall goal that is one of the answers we hope that our research will be able to give us someday.”
Since White-nose Syndrome was first detected in Missouri in 2010, several organizations, including the Missouri Bat Census, have been organized. Executive Director Kirsten Alvey-Mudd helps lead teams of volunteers to survey around 400 caves across the state.
“The Missouri Bat Census helps do things from rescuing, rehabilitating and relocating sick or abandoned bats to helping scientists or researchers survey sites for White-nose Syndrome,” Alvey-Mudd says.
By helping conduct these surveys, The Missouri Bat Census hopes to help scientists prevent the spread of the disease from reaching out to all 7,000 caves in Missouri.
According to Alvey-Mudd, only eight counties had confirmed cases, through histological testing, of White-nose Syndrome in the winter of 2014-2015. Although data is still being collected for the winter of 2015-2016, Alvey-Mudd said that seven new counties have reported sightings of the disease, but only two of them have confirmed deaths.
Battling with bacteria
Amelon is one of several researchers who are currently working on a treatment using a strain of bacteria called Rhodococcus rhodochrous DAP 96253 to inhibit the growth of the fungal disease. RRDAP 96253 may not sound familiar, but it is commonly found in soil and was originally tested to see if it would delay the ripening of fruit.
Christopher Cornelison, a postdoctoral researcher with the Georgia State University conducted a study on this strain of bacteria published in 2014. The goal of this study was to see if the strain had any affect on P. destructans. Cornelison wondered if the bacteria would inhibit fungal growth in vitro, and indeed it did. Once the study proved to be a success, Cornelison reached out to Amelon in the winter of 2013 to begin testing the treatment at the University of Missouri.
“He wanted to move on to testing how bat tissue reacted to this bacterial strain,” Amelon says. “We began by collecting very few [bat] numbers to test it, but once it started to become more and more successful, we had to expand the number of bats we were testing.”
All testing that uses RRDAP 96253 is done in a laboratory within the Department of Fisheries and Wildlife at the University of Missouri. The exact process of the testing won’t be revealed until all trials of it are complete, Amelon said.
Amelon says that she and her team have seen some improvement in bats treated in the labs, especially when compared to current mortality rates in some species.
Amelon and other researchers hope to finish testing within the next few months to begin field trials in Missouri and other states. The field trials will involve adding the soil bacteria to the floor and walls of various hibernation sites. The bacteria will then create volatile, or airborne, compounds that will come into contact with the fungus in shared airspace. Like it does with the fruit, the bacteria will target the spores of the fungi and stop them from growing or spreading any further. “It’s almost a waiting game until spring,” Amelon says. “During the spring, the fungi can become dormant due to the warm weather.”
Amelon hopes to soon be one step closer to finding a solution useful tool against this fungal disease.
“In order to fully understand the fungus we need to know how every species is affected by it and the Rhodococcus,”Amelon says. “To affectively find a solution for these bats, we [researchers] need to take a synergistic approach.”
Other researchers across the country have conducted their own studies to find a solution for White-nose syndrome. In Rolla, Missouri, a senior studying biological science at Missouri University of Science and Technology named Edna Armstrong recently invited Amelon to the campus to speak to the iGEM research team about Amelon’s research.
The team tried to produce ocemene, a volatile organic compound normally found in oranges, and see if it would prevent growth of the fungus during hibernation, when bats are most vulnerable. Although project was not successful, Armstrong said the team will continue to push forward. Armstrong and the iGEM team took part in presenting their research to state legislators in Jefferson City for Undergraduate Research Day.
“It’s unfortunate that all of the research and bat population counts are thanks to White-nose,” Armstrong says. “But it is also good because we have discovered more about bats in the past decade than ever. Educating people about bats is very important not only to their survival but for the health of our world as well.”
Even though treatments are still being tested, there is now a glimmer of hope for fighting White-nose Syndrome. The disease that has been slowly erasing North America’s bat populations over the past decade might have met its match.