May 30, 2014
UV Light Used As A New Tool To Detect White-Nose Syndrome In Bats
Brett Smith for redOrbit.com - Your Universe Online
The study authors found that when they directed UV light at the wings of bats with WNS, microscopic skin lesions on the animals fluoresce with a distinctive orange-yellow color.
“When we first saw this fluorescence of a bat wing in a cave, we knew we were on to something,” said study author Greg Turner from Pennsylvania Game Commission, who said he has been using the UV technique since 2010. “It was difficult to have to euthanize bats to diagnose WNS when the disease itself was killing so many. This was a way to get a good indication of which bats were infected and take a small biopsy for testing rather than sacrifice the whole bat.”
Caused by the fungus Pseudogymnoascus (Geomyces) destructans, WNS has killed millions of bats and been detected across 25 states and 5 Canadian provinces. The study team said they wanted to resolve inefficiencies in surveying hibernating bats for the disease. The existing method involves euthanizing bats and taking them back to a laboratory for testing.
“Ultraviolet light was first used in 1925 to look for ringworm fungal infections in humans,” said study author Carol Meteyer, a scientist with the United States Geological Survey. “The fact that this technique could be transferred to bats and have such remarkable precision for indicating lesions positive for Pd invasion is very exciting.”
To test the ultraviolet light method, bats with and without white-nose syndrome in North America were tested first using UV light, then using traditional histological means to authenticate the UV light’s accuracy.
USGS researchers found nearly 99 percent of bats with the orange-yellow fluorescence tested positive for white-nose syndrome, while all of those that did not fluoresce tested negative for WNS. Biopsies revealed that areas of fluorescence matched the microscopic wing lesions that are a hallmark for WNS.
Next, scientists in the Czech Republic used the UV light technique in the field, deploying it to gather small samples from sections of bat wing that glowed under UV light. These scientists found that almost 96 percent of wing biopsies that fluoresced tested positive for WNS lesions. Once again, all of bats that did not glow were negative for the disease.
Merging work from two groups showed that UV diagnostics might be useful internationally with great sensitivity and specificity in finding WNS, the study researchers said.
“Moreover, the technique hurts the animal minimally and bats fly away after providing data for research,” said study author Natalia Martinkova from the Academy of Sciences of the Czech Republic. “This makes UV fluorescence an ideal tool for studying endangered species.”
With the spread of WNS, scientists are becoming more interested in tracking the make-up of potentially endangered bat populations.
Earlier this week, a study published in the Journal of Ecology and the Natural Environment found installing a row of audio sampling detectors for a week then moving them around to cover a large area could more effectively gauge the size and types of bat populations than setting up permanent stations.
Conducted around Fort Drum in upstate New York, the study noted that the work was partially motivated by the Army’s need to determine its impact on the local bat population. Many bat populations in the area have been decimated by white-nose syndrome.