In the winter of 2006, scientists noticed bats flying during the day when they should have been hibernating.
When they examined the bats up close, they discovered a white, fuzzy accumulation on their noses, ears and wings. This led to the name “white nose syndrome.”
The scientists quickly determined that the fuzzy material was a fungus, Pseudogymnoascus destructans.
White nose syndrome has spread from the initial discovery in a cave near Albany, New York, making circles like radar on a map.
The bat disease reached northwestern Ontario this year and will likely arrive in Manitoba within a year or two.
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This disease spread is similar to how West Nile moved south and west from its initial location in New York state. Some estimate the rate of spread at 200 kilometres per year, which would see the disease reach Canada’s western shores in a fairly short time frame.
The infection is thought to spread between bats by direct contact. Fungal spores can also survive well in cave environments. For example, researchers have identified positive fungal samples in soil and cave walls.
However, humans may play an even greater role.
People who visit bat caves and abandoned mines may carry the fungi over great distances.
In fact, most white nose syndrome experts believe the fungus was accidentally introduced by people from Europe.
Ongoing research has discovered that the fungi is found in Europe but does not cause widespread mortality in that continent’s bats. The rapid spread and exceptionally high mortality rates in North America suggest the fungus is new and that bats have no immunity.
The fungus poses no risk to human health, but cavers could easily spread it to uninfected caves. Fungal spores can easily contaminate clothing and equipment, so it is crucial that cavers do not use the same gear between caves in eastern North American and those in western North America.
Infected bats awaken too often and far too early, well before the insects they eat are available. Any stored fat is quickly used up.
The fungus also directly damages the skin and causes dehydration. Most bats die of starvation and dehydration rather than directly from the fungal injury.
The curious thing about hibernating bats is they have limited immune responses during this time.
As well, the fungi hit when the bat’s immune defenses are at their weakest. Only hibernating bats are infected, which is attributed to their lower body temperature that favours fungal growth and weakened immune system.
White nose syndrome has devastated bat populations in Eastern Canada and the United States. Up to 99 percent of bats can die when the fungus shows up in a previously uninfected cave,. This amounts to roughly six million bat deaths since the outbreak began.
In Canada, the disease has been particularly hard on northern long-eared bats, little brown bats and tricolor bats and has nearly wiped them out in eastern provinces.
Because of this, the federal government has designated all three bat species as species at risk, which will provide legal protection and require a species recovery plan.
With only one baby born per year, it will take bats decades to recover, if they can at all. There is also the risk of continual infection from the environment. The fungus could possibly infect new bats if they are introduced or recover elsewhere and subsequently visit an infected cave.
Bats have a central role in ecosystems through their gluttonous consumption of insects, including agricultural pests.
If bats become extinct, this important pest control role will no longer be filled. Some estimate that the potential economic impact of white nose syndrome on agriculture will be in the billions of dollars.
Decimation of any species at such a rapid rate is unprecedented in Canada. With no effective control measures and no treatment or vaccine, the situation for bats is bleak indeed.
