Scientists probe bat-killing fungus

White-nose syndrome studied at Western Connecticut State University

DANBURY — Two local researchers are trying to find a quicker, cheaper way to detect a fungus that has killed millions of bats, and in some cases, wiped out entire cave populations in North America.

More than 6 million bats have died since white-nose syndrome appeared in the U.S. about a decade ago.

In Connecticut, the little brown bat, the tri-colored bat and the northern longeared bat have lost significant numbers.

The disease is caused by a fungus, Pseudogymnoascus destructans, which infects hibernating bats’ muzzles, ears and wings, giving the disease its name. Two main techniques are used to find this fungus, but one isn’t very effective and the other is too expensive for most to use because it requires a machine that costs at least $10,000.

“We’re trying to make it cheaper and easier to detect,” said Hannah Reynolds, an assistant biology professor at Western Connecticut State University.

University, who has spent the summer working with Jasmine Grey, a junior at the university, to develop a new method.

Rapid testing

The goal is to accomplish the same results without the machine. Ideally, a person can swab a bat or cave, test the sample in about 35 minutes and see if a gene specific for that fungus is present, and showing the fungus itself is there.

“The more we have data on where white-nose syndrome is, the more we can work to solve the problem and save the bats,” Grey said.

The test was developed for a rapid response to human pathogens, such as malaria. It has since been used in agriculture to see if a pest is present in a field.

Reynolds was inspired by the success at the plant level to try it with wildlife.

They said it was important to save the bats because of their role in the ecosystem. The bats eat insects that can damage crops or spread illness. Bats only have one pup a breeding season, which makes it harder for them to recover from the population loss.

“They don’t reproduce as quickly as other small mammals do,” Reynolds said.

White-nose syndrome was discovered in 2006 in New York. It has since spread to 33 states in the U.S. and seven Canadian provinces. In some areas, 90 to 100 percent of the bats have died. It was confirmed in Connecticut in the winter of 2007-08 with sightings in the northwestern part of the state.

It is believed the fungus is largely spread by human activity. Several caves have closed to the public, including Tory’s Cave in New Milford, to prevent the spread of the fungus being tracked in on people’s clothes or boots.

Fungi genetics

Three distinct genes separate this fungus from the other fungus.

Reynolds and Grey are honing in on one specific gene to see if the fungus that causes white-nose syndrome is present.

This testing method, called loop amplification mediated PCR, or LAMP, replicates specific pieces of DNA to help see if a gene is present. This is done by adding samples of DNA into prepared solutions of primers and then heating at a certain temperature. The primers attach to a certain gene and amplify it. The trick is to amplify just that gene without amplifying other genes present in the similar fungi.

Reynolds said finding what isolates that one gene is the hardest part, especially because the fungi are so similar.

Grey has determined the most successful ratio of primers and is playing with the heat to make it more specific. The machine allows each well to have a separate temperature so they can test 12 different temperatures at once.

The duo is using samples of the fungus that causes the disease, as well as similar fungi, to see which chemical solution and temperature best identifies that gene. They are working with 32 samples, mostly from the Northeast, and a mix of the fungus found on bats and cave walls.

“Most of them are nontargets,” Grey said. “It’s more important to make sure they don’t amplify so we have more them."

The summer work on the detection method ended Thursday but the duo will resume when school starts in a few weeks. Grey will continue to optimize the technique with the hopes training conservationists and land managers at parks to test.

“I feel really good about the progress we’ve made,” Reynolds said. “Now we can hone in and make it as specific as possible.”

Marvin Moriarty / Associated Press file photo This March 26, 2009 photo provided by the U.S. Fish and Wildlife Service shows a little brown bat with white-nose syndrome in the Greeley Mine in Stockbridge, Vt.

Carol Kaliff / Hearst Connecticut Media Jasmine Grey of Naugatuck, a junior at Western Connecticut State University, holds a tray of DNA samples taken from different fungi.