Bat Virus on the Move
A lethal disease called white-nose syndrome (a fungal virus) has killed at least six million North American bats over the past ten years. Since white-nose syndrome first appeared in Albany, entire bat species now face the potential of being annihilated.
Thomas Lilley, postdoctoral fellow at Bucknell University, helps wild bats acclimate to life in captivity. He and others are working to understand white-nose syndrome. The fungus assaults bats while they hibernate in caves. Researchers are examining normal bat hibernation as well as arousal bouts, which are a big part of understanding the problem.
Hibernating bats warm themselves out of torpor (inactivity) every few weeks during the winter and for several hours at a time. And while researchers do not comprehend the reasons for the arousal bouts, they do know how important these periodic thaws must be to the survival of the bat.
“All the work that bats do during the fall, feeding nonstop and putting on fat until they’re like butterballs on wings, and 90 percent is spent to sustain the winter warm-ups,” said DeeAnn Reeder, a professor of biology and leading bat ecologists.
It is believed that white-nose syndrome disrupts the arousal-torpor cycle. This occurs long before any symptoms manifest. A white fuzz appears on the bat’s face and wings. The disorder exacerbates when bat’s immune systems mount a strong response against the fungal spores.
This is not typical as scientists are discovering that bat immune systems are surprisingly tolerant of most pathogens. This trait offers clues to preventing aging diseases in humans such as cancer.
“At this stage, the evidence is anecdotal,” said Lin-Fa Wang, a bat virologist at the Duke-NUS Graduate School in Singapore and the Australian Animal Health Laboratory in Geelong. “But of all the bat biologists I’ve spoken with, I’ve only heard of one or two cases of bat tumors.”
Researchers are scrutinizing bat DNA. Preliminary findings indicate that bats’ apparent indifference to the viral hosts they harbor, together with their longevity, probably arose from adaptations needed to grant them the power of flight.
Regardless, bats play crucial roles in our environment. Bats that consume tons of insects are apex predators among night-flying insects including mosquitoes. Reeder estimates that ‘for every million bats killed by white-nose syndrome, 692 tons of insects go unchecked every summer.” And fruit- and nectar-eating bats are important for pollination and seed distribution.
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