Biologists watching for avian flu in seals

Fisheries and Oceans Canada photo Seals are shown on Sable Island.

HALIFAX – Marine biologists in the Maritimes are on the alert for seals with avian flu after cases were discovered in Quebec and Maine.

Reports of seal strandings here haven’t seen a spike, unlike in Quebec and Maine where an unusually high number sick or dead started washing ashore in the spring and early summer.

But Tonya Wimmer, founder of a not-for-profit that monitors marine animals in distress and collects dead ones around the three Maritime Provinces, said reports of seal strandings here have been seeing an uptick over the past few months, and her group doesn’t have the capacity to get to them before they decompose in the summer sun or get washed out to sea.

“A lot of the animals are just too far gone by the time we can get there,” she said in an interview. “Some of them, clearly, have a shark bite, but we don’t actually know if there are other underlying conditions with some animals if we see them dead. We don’t know if it’s natural, we don’t know if it’s avian flu or something completely different.”

She said her group, Halifax-based Marine Animal Response Society, has only managed to swab one dead seal, which was from Cape John, N.S., on the Northumberland Strait. The avian flu test came back negative.

“We’ve only had the capacity to sample one animal to date, largely because we don’t have the resources nor adequate freezer capacity,” she said.

Wimmer is puzzled why the Department of Fisheries and Oceans Canada (DFO) isn’t devoting more resources to find signs of the deadly H5N1 avian influenza in seals in the Maritimes.

“I don’t think we or the vets are raising an alarm, saying, ‘Oh my god, it’s in our seals,’ but we should at least be looking,” she said. “We’re trying but it is very difficult if you don’t have the resources to be able to do that.”

Wimmer said her group gets some funding from DFO for the operation if its toll-free hotline, but not to support sampling or diagnostics for looking for wildlife disease, especially in seals.

Damian Lidgard, an aquatic science biologist with DFO in Dartmouth, said the department isn’t actively looking for dead seals. Instead, he said, it’s relying on the public for alerts and Wimmer’s not-for-profit to collect samples and carcasses.

Lidgard said DFO sampling is limited to the times and places when he and other DFO biologists are in the field working with local seal populations.

Such an opportunity is coming up this month, when they deploy satellite transmitters on harbour seals and, later, during the winter months, on Sable Island, he said.

“We will take samples from live and any dead seals that we may find,” he said. “DFO Maritimes is certainly keeping track of any cases and taking opportunities to collect samples.”

The autumn bird migration and the winter grey seal breeding season is cause for concern, he added.

DFO spokesperson Lauren Sankey said the department increased the capacity to necropsy dead seal carcasses and sample for avian flu in Quebec when reports of dead seals jumped. In the Maritimes, the numbers aren’t unusually high, she said.

“Requirement for additional work will be assessed as needed moving forward.”

The highly pathogenic influenza’s relentless spread in migratory wild birds and poultry flocks across North America this spring, and persistence through the summer, is worrying because of its potential to hit other species, or even start a global outbreak in humans.

“The reason we want to know what’s happening in seals is because we want to know what’s going on with this virus in general,” said Dr. Megan Jones, regional co-ordinator for the Atlantic division of environmental conservation group Canadian Wildlife Health Cooperative. “We know that flu viruses are very good at jumping between species and acquiring mutations as they travel between species … It could become more infectious to people. It could have a bigger effect on birds or seals. We just don’t know, unless we’re tracking it and detecting it.

“We also want to make sure all animals are as healthy as they can be,” added Jones, whose career is focused on understanding disease in wild animals.

Since North America’s outbreak began in Newfoundland before Christmas with the discovery of cases at an exhibition farm, the virus has spread to the Maritimes and beyond. Thousands of wild birds have died, and millions of chickens and other poultry have been culled. P.E.I. and Nova Scotia have found cases in foxes. In other parts of Canada and the United States, skunks, raccoons, bobcats, mink and a black bear have been infected.

Jones, who’s also an assistant professor with the Atlantic Veterinary College at the University of Prince Edward Island, said she’d like to be doing more testing on seals in Atlantic Canada, though mortality rates don’t seem unusually high at this point.

“It’s different than the situation with birds because there were clinically infected birds dying in front of people on beach,” she said. “There was a mass mortality rate in many different species of birds that started over the winter and got worse into the summer and started affecting seabird colonies. It’s still going on.”

She said some dead seals were reported in northern New Brunswick early in the summer, but by the time the wildlife health co-operative learned about them, the carcasses were disposed of in a landfill.

Seals, in particular harbour seals, have long been known to be particularly susceptible to flu viruses.

Jean-François Gosselin, a marine biologist for the DFO in Quebec, said reports of dead seals were unusually high starting in May and June.

“Given that influenza was reported in birds all over the place and what we know about seals from incidences in Europe and in the north-east United States previously, it raised a red flag,” he said.

Initial tests on some of the carcasses came back positive and further tests confirmed H5N1, with evidence of lesions in the brains, lungs and other organs that are associated with influenza in mammals.

Of the 30 harbour seals tested through Aug. 23, the most recent data available, 17 were positive. Of the two grey seals tested, one had influenza. A porpoise, minke whale and harp seal were also tested, but showed no evidence of H5N1. Seal carcasses continue to wash up.

The seals are believed to be contracting the virus after beaching themselves to breed or rest and coming in contact with colonies of birds with the virus or their feces.

“Dead birds are showing up all over the East Coast, so it’s likely seals will be showing up with influenza in other areas,” said Gosselin.

The south shore of the St. Lawrence River, where many of the seals were found, is densely populated, which would help with the detection of stranded ones, he said.

“If you’re on the coast of Nova Scotia or Newfoundland, the carcasses might drift away and not be found.”

The Maritimes has no confirmed cases in seals.

“It’s a really nasty virus,” said Jones. “It’s quite heartbreaking to see in a bird or mammal that’s affected.”

While domestic birds can be culled to help stamp out outbreaks, little can be done for seals and other wild animals.

“There’s no real treatment for wildlife,” said Jones. “There isn’t much we can do besides document it and try to minimize any human impact on its spread.”

She recommends people be careful with their pets and dead wildlife.

“I know my dog would eat a dead bird on a beach for sure,” she said.