Bat disease jumps to US west coast

Infected bat (Image: Marvin Moriarty/USFWS)Image copyright

Image caption

White-nose syndrome has now been confirmed in 28 US states and five Canadian provinces

Wildlife officials say they are extremely concerned after a disease that has killed millions of bats has arrived on the Pacific coast of the US.

Until now, white-nose syndrome has only been recorded in the eastern US but the latest case means the fungal infection has jumped 1,300 miles (2,100km).

The killer pathogen, first recorded in New York in 2006, is now present in 28 states and five Canadian provinces.

It has been described as the worst US wildlife health crisis in recent years.

On 11 March, a hiker discovered a sick little brown bat (Myotis lucifugus) while walking in Washington state and handed it in to a local animal welfare centre. Two days later, the bat died.

While carrying out an examination, the centre’s vet noticed visual symptoms consistent with the disease and it was decided to run tests on the dead bat.

David Blehert, from the US Geological Survey’s (USGS) National Wildlife Center, said samples returned “strongly positive” results.

He added: “We have also cultured the fungus… from tissues of the bat, and work that we are continuing to pursue is genetic characterisations of this fungus to see if it is most closely related to strains… that are known to exist in North America or whether it is perhaps more closely related to strains found elsewhere in the world.”

US Fish and Wildlife Service (FWS) spokeswoman Catherine Hibbard said the arrival of WNS in Washington state opened “a new chapter” in efforts to tackle the disease.

“We have hundreds of agencies across the country that are working to solve this problem, including our new partners from the state of Washington,” she told reporters.

“We do not know how this story will go or where it will end but what we do know is that we are in a much better place than we were when white-nose syndrome first hit the east coast almost a decade ago.”

White-nose syndrome

  • WNS is associated with a fungus known as Pseudogymnoascus destructans
  • Once present in a colony, WNS can wipe out the entire population
  • The disease, which appears to target hibernating species, was first reported in a cave in New York state in the winter of 2006-07
  • The most common visible symptom of an infected bat is a white fungus on the animal’s nose, but it can also appear on its wings, ears or tail
  • Other symptoms include weight loss and abnormal behaviour, such as flying in daylight or sub-zero temperatures

(Source: US Fish & Wildlife Service)

White-nose syndrome (WNS) is named after the white fungus that appears on infected animals,

Bats infected with the disease have been observed displaying strange behaviour during winter months, when the animals are expected to be hibernating in caves and mines. It is believed that the disease disrupts hibernation, causing the bats to fly outside into conditions that are too cold and lack food for the small mammals.

The fungus that has been demonstrated to cause WNS, Pseudogymnoascus destructans (formerly known as Geomyces destructans), thrives in dark, damp places such as caves and mines.

‘Local extinctions’

A series of studies have painted a bleak picture for at least half of US bat species, which rely on hibernation for winter survival and are therefore potentially susceptible to the disease.

Writing in the journal Science in August 2010, a team of researchers warned that some species’ populations could become locally extinct within two decades.

Another team estimated the loss of bat species, which help control pest populations, would cost US agriculture more than $3.7bn (£2.6bn) a year.

Studies have also attempted to develop a better understanding of the fungus itself and how it affects bats in different parts of the world.

A 2012 paper described how the fungus was found in populations of bats in Europe without triggering mass mortality. Earlier this month, researcher published details of a study that showed bat populations in China displayed a strong resistance to the fungal infection.

They added that the findings suggested that some US bat species might develop an ability to fight the disease.

US FWS national white-nose syndrome co-ordinator Jeremy Coleman said the first step after this confirmation of WNS would be to conduct surveillance near where the bat was found to determine the extent of the fungal infection in the area.

Officials also confirmed in a media conference on Thursday that WNS had been confirmed in Rhode Island for the first time, a state in the New England region of the US.

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