Brief Overview on White-Nose Syndrome in Bats

About the Study

White-Nose Syndrome (WNS) is a fungal illness that has caused a major decline in the bat population in the United States and Canada reportedly killing millions of bats as of 2018. A characteristic fungal growth around the muzzles and on the wings of hibernating bats gave the disorder its name. It was discovered after a snapshot taken in a cave in Schoharie County, New York in February 2006. However, the syndrome has expanded fast. It was discovered in 33 U.S. states and seven Canadian provinces in early 2018 as well as the fungus without the condition in three more states. The majority of cases are found in the eastern half of both countries however it was confirmed in a tiny brown bat in Washington State in March 2016. The fungus was discovered for the first time in California in 2019 with no infected bats was reported.

The fungus Pseudogymnoascus destructans which colonises the bat's skin causes the sickness. There is no evident therapy or way to prevent transmission and some species have decreased by more than 90% within five years of the disease's arrival. The US Fish and Wildlife Service (USFWS) has asked for a halt to caving activities in the impacted areas and strongly advises that clothes and equipment be decontaminated after each usage. The National Speleological Society keeps a current page up to date to keep cavers informed about current events and recommendations.

WNS is caused by Pseudogymnoascus destructans. It prefers temperatures between 4 and 15 degrees Celsius (39 and 59 degrees Fahrenheit) and will not grow above 20 degrees Celsius (68 degrees Fahrenheit). It is psychrophilic or cold-loving. It's phylogenetically related to Geomyces spp., but it has a conidial morphology that's different from the genus. The fungus was originally classified in the Geomyces genus but phylogenic analysis suggested that it should be reclassified as Pseudogymnoascus.

According to a 2011 study, 100% of healthy North American bats infected with the fungus cultivated from infected bats exhibit disease-like symptoms. The fungus has invaded the skin of WNS-affected bats, according to direct microscopy and culture investigations. The species has been detected on bats throughout Europe and Asia but the infections have not been linked to any particular mortality. According to genetic analyses, the fungus must have been present in Europe for a long period before being introduced to North America as a unique infection. Because bats in mesh cages adjacent to infected bats could not develop the fungus, a laboratory experiment implies that physical contact is essential for one bat to infect another. This means the fungus isn't airborne or at the very least isn't passed from bat to bat through the air.

Bat-to-bat contact or infected cave-to-bat contact is the most common mechanism for this fungus to spread. The role of people in the disease's propagation is debatable. Because no bats naturally migrate between Europe and North America, and the fungus was initially detected in New York where there are significant trans-Atlantic air and shipping facilities. It seems likely that the fungus was transferred to North America by human activities. Bats have been transported across continents by ship and aeroplane. Although research has revealed that the fungus may persist on human clothing and hence be moved between areas by people. It has yet to be proven that this has played any role in the disease's transmission as of 2016.