Killer bat disease on the move

 

A virus that devastated bat populations in the US has arrived in Europe – but something is different, writes DICK AHLSTROM

A MYSTERY disease that has wiped out bat populations across the American north-east has now been discovered in Europe. A University College Dublin research team confirmed the fungal disease in a bat recovered in France.

“This is a dreadful disease,” said Dr Emma Teeling, of UCD’s School of Biology and Environmental Science, who led the research. “People were shocked because you get 100 per cent mortality.”

And for those who would hold little sympathy for something as creepy as a bat, think again. Bats eat their way through millions of insects, including many agricultural pests. The loss of bat populations would cost US agriculture an estimated $1 billion annually, Teeling suggests.

She and her colleagues from UCD and France are the first research team to confirm the presence of the deadly fungal agent Geomyces destructansin a European bat.

The organism causes White Nose Syndrome, first identified in New York State in 2006. The disease spread rapidly across the US north-east, killing more than a million bats and there are fears there that bats right across the US are at risk.

Now the disease has been found in a bat recovered near Perigueux in France. “Our results provide the first conclusive evidence for the presence of G destructansin European bats,” Teeling says.

Details of the Science Foundation Ireland-funded research have been published in the online version of the Journal of Emerging Infectious Diseases.

“People were surprised how a fungus could kill a mammal,” Teeling says. “It is quite an unusual fungus because it likes the cold.”

Bats take to caves and underground hibernation sites when the weather turns in October/ November. There they wait out the cold months until things warm up in April.

G destructanssomehow reaches the hibernating bats, spreading despite the cold. Once infection sets in, it leaves the bats depleted, too thin and weak to fly off when spring comes, so they simply die off, Teeling explains.

Given the damage being caused by the disease in the US, there were fears that something similar might happen on this side of the Atlantic, she says. “European bat workers were terrified.”

Teeling’s post-doctoral fellow, Dr Sebastien Puechmaille, had good contacts with French counterparts and a search for infected bats got under way. There were reported sightings of bats with unusual white noses, and soon one was spotted in France and caught.

Once brought to Ireland, the team conducted a detailed analysis of the white fungus. UCD’s Dr Hubert Fuller, an expert in funguses, cultured spores and these underwent a detailed genetic analysis, focusing on two genes characteristic of G destructans.

The cultured spores had the same unusual curved shape described by US researchers, but the real confirmation came after the genetic analysis, Teeling says. The European sample had “a 100 per cent sequence identity with the US fungus”, leaving no doubt that the European bat was carrying G destructans.

This discovery served to raise many more questions, Teeling says. Was the fungus somehow transferred across to Europe or was it already present? Are European bats at the same risk as their US cousins or have they some level of immunity, given that researchers have not yet discovered bats dying in numbers from the infection?

“Europe needs to come in now and collaborate with the US,” she believes. “We have to look at it globally.”

She is fearful that bat populations in Europe will succumb to the disease, a worry strengthened by her discovery that the spores here are a perfect match for the deadly US version. Yet the captured bat emerged from hibernation fat and healthy despite its infection, raising the possibility that bats here might have some immunity to the organism.

Teeling has yet to discover whether G destructansis present in Ireland. The challenge here is that bat hibernation sites have yet to be found.

“We don’t know where they hibernate. They probably go underground, but we can’t find them,” she says.

Meanwhile, she and her collaborators have started to study the bat immune system, looking for genes associated with fungal resistance. If European bats have immunity, reproducing this could protect US bat populations.