The Wildlife Center of Virginia has been caring for two Little Brown Bats who are suspect cases of White-nose Syndrome (WNS). This syndrome, which disrupts bats’ winter hibernation and may cause white markings on the nose or other body parts, is thought to be responsible for the deaths of 5.5 million bats since its discovery in 2006. In a 2011 study, Scientists for the U.S. Geological Survey proved the cause of WNS to be a fungus known as Geomyces destructans.
The fungus itself does not kill the infected bats, but instead interrupts the hibernation that is critical for their survival during winter and in many cases invades the dermis [the inner layer of the skin], causing lesions in the wing membranes. The fungus is spread by contact between bats, but may also travel between caves on clothing and equipment. As a result, universal precautions have been established to attempt to prevent further spread by human activity in these sensitive environments. To date, WNS “has now been found in 16 states and 4 Canadian provinces” (USGS); in some affected areas, the bat population has declined by 80 percent. This may have serious consequences for agriculture; it is estimated that each year bats contribute $3.7 billion to the US economy by eating insects that eat crops.
Little Brown Bat #12-0002, an adult female, was admitted January 1 after being found, ‘dazed and confused’, on a sidewalk in Bridgewater, Virginia. Upon examination the bat was found to be dehydrated and thin. These findings, and the timing of its rescue, correlated to a bat whose hibernation had been interrupted. Center vets administered fluids and rehabilitators initiated a twice-daily feeding program; a few days later the bat was observed to be moving well, able to fly, and very vocal. She was transferred to permitted rehabilitator Leslie Sturges of the "Save Lucy Campagin" on January 7.
Little Brown Bat #12-0111, an adult male, was admitted March 2 after being rescued by dog owners in Folks Run, VA, who discovered it being nosed by their dog. Further examination revealed it to be dehydrated, with dry wing membranes and areas of matted fur on its stomach. Though the bat had contact with the dog, the Virginia Health Department did not believe euthanasia of the bat for rabies testing was warranted. Center vets began treating the wings topically with antifungal cream, and the bat’s weight stabilized after a few days of intense feeding.
In both cases, the bats’ wing membranes eventually developed lesions which degenerated and became holes. Bats’ wing membranes do more than allow flight; they also assist thermoregulation and fluid balance. It is only recently that scientists have come to understand that bats’ wings can regenerate if they have enough fluid, warmth, and nutrition to support the process. Both bats’ wings are slowly healing, and on March 20, Little Brown Bat #12-0002 returned to the Wildlife Center to keep patient #12-0111 company during their convalescence Dr. Miranda Sadar lists their prognosis as ‘Good’ and Center vets are hopeful that they will be released later this year.
Both cases are termed ‘suspect’ because the only currently available testing method with high diagnostic value must be conducted post-mortem.
April 23 update
WHSV interviewed Dr. Miranda on Friday, April 20 -- watch the video here and see these two bats! Both remain bright, alert, and responsive and are maintaining weight.
May 9 update
On May 6, the veterinary team decided to test fly both bats in the Center's new aviary. The staff set their expectations fairly low, since the bats have spent the long winter recovering in a small indoor enclosure. Bat #12-0002 managed to make a few short flights before landing on the ground; Bat #12-0111 didn't do well at all. Both bats are a little overweight, which is hindering their flight capabilities. Dr. Adam also thinks that Bat #12-0111 needs a little more time for wing membrane growth and recovery, since part of the bat's membrane on one wing is still reduced.
Both bats will be put on a diet, and weight will be carefully monitored. They are being housed indoors right now, but as their flight capabilities improve, they will likely be moved to the Center's songbird aviary for flight conditioning.
June 25 update
In early June, both bats were transferred to permitted bat rehabilitator Leslie Sturges of the "Save Lucy Campagin". Both bats lost a little more weight, making them closer to being "fit" -- though without any flight conditioning, the bats needed a larger space to continue their recovery process. Since both bats' wing membranes had healed nicely over the winter, the staff decided that Leslie's expert care and specialized bat enclosures would be much better for the bats' conditioning.
The Little Brown Bats were packed up and transported to Leslie -- and sadly, Leslie reported that one of the bats, #12-0111, died during transport. Leslie sent the bat off for a necropsy to see if a cause of death could be determined. She noted that the bat's body condition was fine -- if anything, the bat was still a little overweight. The other bat, #12-0002, settled in with Leslie and her other bat patients.