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White-Nose Syndrome Still Threatening Bat Population

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February 13, 2012 by Devils Den

DDD bats

By Rebekah Penny, Interpreter, Devil’s Den State Park

Although there have been no confirmed cases of White-nose Syndrome in Arkansas, all federally and state-managed caves have been closed since 2010, including the caves of Devil’s Den State Park.

The closures resulted from the threat of an extremely deadly fungal infection that has been wiping out large population of bats across the northeastern half of the United States and Canada. As researchers have only been following the disease since it was first noted in the winter of 2006 in a cave in New York, there are many more questions than answers. However, new evidence suggests that the repercussions of this deadly disease could affect us all (Consider that this fungal pathogen has been compared to the Potato Famine of Ireland).

At this time, White-nose Syndrome is not believed to be a direct threat to hu- man health. However, it is wiping out bat populations. And whether you recognize the importance of these furry, flying mam- mals or believe the many misconceptions about them, there is no denying the vital and beneficial role they have to humans and ecosystems across the country.

It has been estimated that bats provide over $22 billion in crop protection annual- ly by eating many pest insects. Protecting food crops from pest is beneficial in cost and health to the farm industry. Without bats, farmers will be inclined to use more pesticides, which are costly and leave unhealthy residues that we may ingest or that get into the soil and water cascading through many ecosystems with detrimental effects. Bats are also critical species within cave food webs and play a role in protecting forest and prairies from being attacked by pest.

White-nose Syndrome is known to be caused by the fungal spore, Geomyces destructans. Geomyces destructans is a cold- loving spore. Once in the right conditions, the spores are able to germinate and grow. When in a cave with bats, it will grow across the soft tissue of the muzzle and wings of the bats using them as a host. It is a white, fibrous growth; hence the name White-nose Syndrome. New evidence revealed that the microscopic spores can persist without bat populations being present. Meaning it could be a potential threat for surviving bats for years to come.

Early estimates feared that up to 1 mil- lion bats had been lost to the disease. However, it is now believed that 5-6 mil- lion bats may have already been eradicate with whole population being wiped out and entire species being at risk. Many bat species are particularly susceptible to pathogen transmissions due to their clustering behavior. Their demise is exacerbated by their limited energy resources during hibernation, when they are being introduced to the spores and their slow re- productive rates.

It is not clear at this time whether the disease is causing the bats to wake up during hibernation and starve to death with no resources being available, or whether the wing damage caused by the infection is disrupting critical physiological func- tions such as heat dissipation, hydration, and gas exchange. What is known is that the disease is deadly, and it is spreading at alarming rates. If current transmission rates persist (2,200 km in four to five years), it could be across the United States, reaching 12 more species of bats, within the next decade.

Unfortunately, humans may be accidentally spreading the disease without even knowing it. It is a microscopic, soil fun- gus. You could pick it up on the bottom of your shoe, a backpack strap or hat and not even know it. Once in an area, it can spread from bat to bat and quickly move into surrounding areas. Sadly, with con- firmed cases in Tennessee and Kentucky and suspected cases in Missouri and Oklahoma, it is necessary that the caves of Devil’s Den State Park remain closed to the public. It is also advisable that individual visiting infected areas of the country decontaminate their clothing and equipment before venturing into other areas of the country.

During the annual bat count at Devil’s Den State Park, in which the interpreters joined Blake Sasse, Mammalogists for the Arkansas Game and Fish commission to check on the bat populations of DDSP, no evidence of the deadly fungus was seen. However, it has been suggested that the disease may not be detected in its early stages. Swabs were taken from bats and the cave environment for further testing. At this point the cave hibernating bat populations of DDSP, which include the tri-colored bats and two endangered species the Indiana bat and the Ozark Big-eared bat, appeared healthy. We will continue to monitor the bats found on the park and educate the public on this deadly threat. Our efforts depend upon the public’s co- operation and understanding of this deadly disease.

For more information or to share your comments, you can contact Rebekah Pen- ny at rebekah.spurlock@arkansas.gov

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