A third silver-haired bat has tested positive for rabies in Banff National Park.
The medium-sized bat was discovered lying on the ground in distress in the Lake Louise townsite on Oct. 9. It was sent to a lab for testing and the results came back last weekend.
This most recent case follows two confirmed cases of rabies in silver-haired bats in the last couple of months – one in Lake Louise and another at the Cave and Basin in Banff.
Parks Canada officials say there have been no other reported cases of rabid bats in the past 20 years in Banff National Park.
“It came back positive for rabies,” said Seth Cherry, wildlife ecologist for Lake Louise, Yoho and Kootenay field unit, noting it’s interesting it’s another silver-haired bat.
“Having three cases kind of clumped together here is something we’re interested in, and we’re definitely continuing to monitor it.”
Due to their solitary nature and avoidance of humans, little is known about silver-haired bats in Alberta.
The species lives throughout North America and while they are most abundant in the northern Rockies, they appear to be present in southern Alberta only during spring and fall migrations.
Limited information suggests some migrate seasonally from Arizona to northern Alberta. Males do not appear to migrate and, therefore, records in Alberta include only adult females during spring, and females and juveniles during fall.
In Alberta, silver-haired bats use tree roosts during summer. They’ve been found under bark, in abandoned bird’s nests or hanging upside down among leaves throughout the forests of central Alberta.
According to limited research, they hibernate in the southwestern United States in winter, under the bark of trees, in rock crevices and, very occasionally, in buildings. Specific locations of summer and winter roosts are unknown.
“This is one of the species we think migrates at this time of year,” said Cherry.
“Whether or not that has something to do with us detecting them because they’re on the move, we don’t know.”
Rabies is a viral disease transferred through saliva that affects the central nervous system and brain of animals and people and if untreated is almost certainly fatal to people.
However, contracting rabies from a bat is extremely rare. The number of infected individuals differs from year to year among bat species in Alberta, but is consistently low, with about four to six a year on average.
So far this year, there have been six cases of rabid bats confirmed in Alberta. Last year, 10 bats tested positive for rabies.
According to Alberta Environment and Parks, the prevalence of rabies in suspect silver-haired bats – those bats acting strange or on the ground – is erratic, ranging from zero to 18 per cent.
“Prevalence is affected by the low number of these bats tested,” according to the government department’s website.
Rabies has also been diagnosed in several other bat species in Alberta, including big brown bat, hoary bat, little brown bat and western small-footed bat (a single individual).
The extensiveness of rabies in endangered little brown bats, the most common bat species in Alberta, decreased significantly in the 1970s and the virus has all but disappeared in this species since then.
The prevalence of rabies in big brown bats is consistently five per cent to 10 per cent of the big brown bats tested.
“The number of hoary bats submitted for testing is too low to establish the rate of infection,” according to the website. “Very few rabid hoary bats are found.”
The last Canadian to die from rabies was Albertan Emil Fuyarchuk, in 2007. He was bitten in his sleep by a bat in his rural Alberta home east of Edmonton. He didn’t seek treatment and was dead eight months later.
Anyone who sees a bat displaying abnormal behaviour, or a dead bat, should contact Parks Canada dispatch at 403-762-1470.
