White-nose Syndrome Threatens Northeastern Bats

One of the scary things about the emergence of a virulent new epidemic that is new is how little we know about its causes and how little time there is to act to contain its spread.  Even with outbreaks where the causes and treatments are understood by science, it is generally true that the longer the lag between detection and response, the more costly the remedy and the less likely it will lead to complete eradication. 

This is true not only for the diseases of humans but also those pests and pathogens that affect plants and animals.  The spread of what is being called "White-Nose Syndrome" to more than a dozen bat caves in three northeastern states is a current case in point.

"White-nose syndrome was first discovered last January in caves in eastern New York. Last year, between 8000-11,000 bats died in New York-- the largest die-off of bats due to disease documented in North America."

Thousands of bats have sicked this year as the disease has been detected in an additional cave in the eastern Berkshires, and two more in the southern Green Mountains of Vermont.  Bats overwinter in large communal groups, sometimes numbers tens of thousands of individuals, but in relatively few places around the northeast.  Mortality rates have exceeded 90% in some of the affected caves.  Four species are known to be affected, including the endangered Indian Bat which had been making a comeback in the Northeast.   Little brown bats seem to be taking the hardest hit.

The implications of a massive bat die off could be substantial, given their role in insect control.  Moths and beetles in particular could have a greater impact on crop damage without the predation provided by bats.

The problem is that so little is known about what is causing the die-off.  The Boston Globe reports; "Scientists do not yet know if the fungus is a cause of the illness or an effect. Some of the sick bats behaved oddly, clustering near the entrance of New York caves, flying in winter when they should have been sleeping and crashing into snow banks."  Many but not all of the caves where the disease has been found are popular with cavers, and State and Federal wildlife agencies have called for spelunkers to avoid caves where bats hibernate ti prevent possible contamination.  The Northeast Cave Conservancy has responded by closing all its caves to visitation until May 15th.

Fungi of the genus Fusarium that are widely distributed in soil and associated with plants have been identified with the bat disease.  New York DEC wildlife pathologist Ward Stone hypothesizes that affected bats have weakened immune systems due in part to climate change.  This is by no means a certainty, as the counter argument provided in this thread posted on a caving forum illustrates.  It is possible that there is a combination of stressors at work, as many bats appear to die of dehydration after using up their fat reserves in unusual winter activity. 

In the second year of a new outbreak, hard data is difficult to find and it is prudent to err on the side of caution.   

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Comments

[Rob Miller]

Wow. This is scary. First the bee syndrom and now this. It seems that we are right on the verge of a major breakdown. Thanks fo rteh reporting.