by Ashley Otto
What is it?
White-nose syndrome (WNS) is a fungal disease that infects bats in North America. This disease is caused by a European fungus Pseudogymnoaseas destructans. The fungus grows on the wings and nose of the infected bat. This disease affects the flying and foraging ability since it deteriorates connective tissues of the wings. The fungus also alters the water balance of the bat, which causes it to arouse every three to four days during hibernation rather than the usual ten to twenty days. When the bat wakes up more frequently during hibernation it can lead to starvation and the use of its fat reserves and ultimately cause death.
This disease is highly transmissible in winter during hibernation due to the close proximity of the bats; the bats also have cooler body temperatures during hibernation, which is the optimal temperature for the fungus to grow. Dr. Kate Langwig and colleagues with the department of ecology and evolutionary biology at University of California did research in 2014 about WNS. Their research shows the infected caves have a 90%-100% bat mortality rate with approximately 100% of the bats becoming infected. Research also showed that the infection rate peaks just prior to females giving birth, when the annual number of bats is at a minimum. The fungus then kills off most, if not all of the bats, thus reducing the reproductive population. The bats that are not killed off and survive hibernation have increased body temperatures that are too high for the pathogen to continue growing and the infection clears up.
Where is it found?
The first documented case occurred in New York in the winter of 2006 and it killed off millions of bats. The origin is unknown, but it is speculated to have begun in Europe or Asia. Currently, WNS is spreading across North America rapidly and it threatens several bat species with extinction. Seven bat species in North America have been confirmed with WNS and they include: Little brown bat, Northern long-eared bat, Tri-colored bat, Indiana bat, Eastern small-footed bat, big brown bat and gray bat. Four bat species that are endangered from this fungus include: gray bat, Indiana bat, Virginia big-eared bat and the Ozark big-eared bat. The following map is the most recent diagram of the known location of WNS. As of March 31, 2016 however, a confirmed case of WNS in Washington state has been found. The presence of this disease was verified by the U.S. Geological Survey’s National Wildlife Health Center. WNS has spread quickly and has killed more than six million bats since it was first documented in 2006.
Why should we care?
Bats play extremely important roles in the environment. Bats can pollinate over 500 plant species: mangos, bananas, cocoa, agave, etc. They are also a great form of pest control since some species eat insects and control the mosquito populations. Some species eat fruit and thus disperse the seeds in their droppings and help spread the range of varying trees and bushes.
How to help?
Treatment is still under investigation, but a strain of bacteria known as Rhodococcus rhodochrous can prevent molds from growing on bananas; so this could slow or kill the fungus growing on the bats. According to National Geographic, research is being done to develop a way to deploy the treatment in caves without waking the bats or having to handle them. If you would like to donate and help the research continue, please visit Bat Conservation International at https://www.supportbats.org/donate.
Other ways you can help the decimated bat populations is to help prevent the spread of WNS by staying out of caves or mines where bats are known or are suspected to hibernate so you do not disturb them. This will prevent them from waking up too early or frequently from hibernation and attempting to forage and using their fat reserves. For those who enjoy cave spelunking and exploring, whether you see bats present or not, please decontaminate all caving clothes and equipment to prevent the spread of the fungus to other locations you explore.
A life without bats would be a truly frightening place. The large amounts of insects and mosquitoes that would swarm us would be terrifying. Insect pests would thrive and wipe out crops across the country. Bats can eat on average 1,200 insects in an hour! The deadly mosquito carries the West Nile Virus, Dengue, Yellow Fever, LaCrosse Encephalitis etc., imagine how prevalent these diseases would become and the huge increase in human casualties. Bats protect us from many of these diseases so we need to protect them from white-nose syndrome.