The Chickahominy Report

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Mysterious bat disease forces closure of caves, mines

Little brown bat (Myotis lucifugus) with fungus on its nose. (Ryan von Linden/New York Department of Environmental Conservation)

Lit­tle brown bat (Myotis lucifu­gus) with fun­gus on its nose. (Ryan von Linden/New York Depart­ment of Envi­ron­men­tal Conservation)

MECHANICSVILLE, Va. — The USDA For­est Ser­vice closed caves and aban­doned mines through­out the south­east­ern Unit­ed States last week in an effort to stem the spread of white nose syn­drome among bats, a dis­ease char­ac­ter­ized by the appear­ance of a white fun­gal growth on the muz­zles, ears, or wing mem­branes of infect­ed bats.

The fun­gus that is asso­ci­at­ed with the syn­drome (Geomyces sp.) thrives in the dark, cool con­di­tions of the caves where the affect­ed bat species hiber­nate. Infect­ed indi­vid­u­als con­sume the fat reserves they need to dur­ing hiber­na­tion too quick­ly and starve. Mor­tal­i­ty rates of 75 per­cent are com­mon, but as many as 95 per­cent of bats in some colonies have died after the dis­ease appeared.

White nose syndrome occurrence by county. (Cal Butchkoski, Pennsylvania Game Commission)

White nose syn­drome occur­rence by coun­ty. (Cal Butchkos­ki, Penn­syl­va­nia Game Commission)

Accord­ing to the U.S. For­est Ser­vice, as many as 500,000 bats have died in New Eng­land and the Mid-Atlantic states in the three years since the dis­ease appeared. Of that total, 25,000 have been the Indi­ana bat (Myotis sodalis), an endan­gered species.

White nose syn­drome was first observed among a bat colony at Howes Cave, near Albany, N.Y., in Feb­ru­ary 2006, the dis­ease has spread to north and east to colonies in Con­necti­cut, Mass­a­chu­setts, New Hamp­shire, and Ver­mont; and south as west to colonies in New Jer­sey, Penn­syl­va­nia, Vir­ginia, and West Virginia.

Evi­dence sug­gests that humans as well as bats play a role in spread­ing the dis­ease. Humans — by har­bor­ing fun­gal spores on shoes, cloth­ing, or equip­ment — may inad­ver­tent­ly trans­port the fun­gus from cave to cave. This con­cern has led to the strat­e­gy of clos­ing caves and oth­er under­ground refu­gia, such as aban­doned mines, that bats may inhabit.

On April 24, the East­ern Region of the For­est Ser­vice closed caves and mines in a swath of north­ern states from Min­neso­ta, Iowa, and Mis­souri east to Maine. The East­ern Region includes West Vir­ginia, where White Nose Syn­drome has been con­firmed from sev­er­al caves in Pendle­ton County.

The South­ern Region fol­lowed suit on May 21 with the clos­ing of caves from Okla­homa and Texas east to Vir­ginia, the Car­oli­nas, Geor­gia, and Flori­da. The South­ern Region’s clo­sure will be in effect for at least a year. So far, Vir­ginia is the only state with­in the region to have con­firmed cas­es of white nose syn­drome — from caves in Bath, Bland, and Giles Coun­ty. There is evi­dence to sus­pect cas­es from Rock­ing­ham and Cum­ber­land Coun­ties as well.

The Cum­ber­land Coun­ty case is anom­alous in that the coun­ty, which is on the Vir­ginia Pied­mont, has no caves. There may be old mines, how­ev­er, where bats may hibernate.

Oth­er fed­er­al and state agen­cies, as well as pri­vate landown­ers and orga­ni­za­tions involved in either bat con­ser­va­tion or cave explo­ration, have joined or are coop­er­at­ing with the cave and mine clo­sure effort.

— David M. Lawrence

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