A Haunting Kind of Fungus Turning Bats into Ghosts

That haunting time of year is upon us where jack-o’-lanterns set the streets aglow with as much imagination as those very minds responsible for carving them. The wind whispers through the falling leaves as both shrilling laughter and shrieks give life to neighborhoods in the dead of night. Snaggletooth witches with ivy green skin congregate alongside werewolves and vapid-eyed zombies in a quest for an expedited way to rot out their teeth.

No Halloween story would be complete without mention of bats! A tortured soul flying through the skies with the sole goal of sucking out your blood. Isn’t that what society conditions children to think? Bats are either disease carriers that will inflict rabies on an unsuspecting victim, or are vampires in disguise! All sorts of images can be conjured up in the mind.  Well this is a different kind of ghost story, featuring the most ghastly of all monsters.

First, we must set the scene! Contrary to popular myth, bats are vital members of our planet. Over 1,300 species of bats around the world are charged with crucial ecological roles that are fundamental to the health of both our natural ecosystems and human economies. Bats consume colossal amounts of insects. Some of their most readily devoured prey are actually agricultural pests! Bats are also highly effective pollinators that can help distribute seeds, even within critically damaged rainforests. Guano (bat droppings) hold power as a valuable natural fertilizer. Just think, even their waste is an important resource! The list of benefits is substantial!

Bats face a number of threats from habitat destruction to hunting and even suffer from natural disasters. Alarmingly, a new danger is on the horizon with frightful mortality rate. One that up until recently has left scientists puzzled. White-nose Syndrome (WNS) is devastating our bat population with an estimated 5.7 million deaths thus far. It is a fungal disease impacting bats in North America. The white fungus appears on the muzzles and wings of animals unfortunate enough to contract the disease, essential providing a ghoulish costume. The fungus called Pseudogymnoascus destructans thrives in cold and humid conditions and is known to invade the skin of hibernating bats. This has serious ramifications on behavior. Inflicted bats will frequently awaken during hibernation. The interruptions cause bats to burn through limited fat reserves as they fly out of the hibernation site in search of food. Often, they become dehydrated and venture into freezing temperatures. The fungus has been shown to be transmitted from bat to bat and is currently observed in 26 states and 5 Canadian provinces. Seven species of bats have been confirmed to be diagnosed with the disease, with another five species testing positive for the fungus responsible.

Researchers have been powerless to bust this ghost causing fungus up until a recent accidental scientific discovery.  Scientists at Georgia State University were analyzing a common bacterium known as Rhodococcus rhodochrous and it’s implications for fruit preservation. When fruit such as bananas are picked, chemical signals are emitted that spark the fruit’s ripening process. This can present a challenge for supermarkets who often import the fruit from thousands of miles away. Often fruit can rot during transit and become spoiled before it is able to stock shelves. This particular bacterium releases Volatile Organic Compounds (VOC) with anti-fungal properties. The original hypothesis was that it could be manipulated in a way that allowed for an effective delaying of ripening in fruit. Along the way, the unexpected result of fungus inhibition emerged. Fruit exposed to the bacterium were not molding.

Chris Cornelison, from Georgia State, decided to test the generalizability of this effect. He exposed petri dishes of the WNS fungus to the bacterium. Results were impressive and it wasn’t long before partner organizations like Bat Conservation International, The Nature Conservancy, and the U.S. Forest Service worked with the team of Georgia State researchers to turn this bacterium into a tool for managing WNS.

Those involved with the study collected wild bats with various levels of WNS. They were placed in mesh bags and put into a large Yeti cooler containing plates of the bacterium. The treatment phase ranged from 24 to 48 hours. Upon completion, the sample bats were strategically placed in an enclosure where they were to dwell in a cave for hibernation. With the emergence of spring, the same bats were collected and once again tested for the presence of WNS.  Much to the researcher’s relief, no bats exhibited signs of WNS and most were able to be released back into the wild. A small number of the bats were deemed unable to survive in the wild due to wing injuries sustained from WNS and are now utilized as animal ambassadors. A total of 75 bats were successfully treated, offering hope to one of the gloomiest horror stories facing bats in modern times.

Researchers are closely investigating more advanced applications for these findings. The bacterium is a biocontrol, which is a biological method for controlling an invasive species. History has suggested that unintended consequences often emerge with such pursuits. It is plausible that the bacterium may impact other native organisms in adverse manners. More research is needed within this realm. Secondly, while the bacterium is effective in inhibiting the growth of the fungus, is not a silver bullet cure. Perhaps this ghost-like fungus that conceals and shrouds bats in certain death will one day evolve into a mere legend, where the corresponding scares are buried forever. The hope is that science will enable us to treat caves, save lives, and end this deadly reign of terror.

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