The photos I've seen show a furry white fungus on their little noses, and patches on their wings. They come out of hibernation while suffering from the disease, and die of cold or starvation. Whole colonies have been wiped out. They're very vulnerable because of their colonising habits and hibernation. I do hope the scientists can find out what's happening. I like bats, and don't know why some people find them unpleasant. Here (UK) it's illegal to disturb a colony, even if it's in your house. They're cute, and eat tons of nuisance insects too.