Saturday, January 22, 2011

Deadly avian cholera threatens ducks in Canadian Arctic - North America also

By Tom Spears, Ottawa Citizen January 21, 2011
A new bird disease has arrived in Canada’s Arctic, one so lethal it can kill thousands of ducks in a dense colony in a lightning-fast outbreak.
Eider ducks stricken with avian cholera can die so fast that they remain upright on their eggs, eyes open. Some fall out of the sky, dead. Others survive unharmed, surrounded by corpses.
Now Carleton University and Environment Canada will get more than half a million dollars to study the disease — which birds get it, how it spreads, why some survive, and how it arrived in the Arctic after decades of existing farther south.
And the study started with a piece of good luck: Scientists were already studying the Arctic ducks before the disease broke out, giving them an unparalleled chance to compare precise data about the birds before and after the disease.
The ducks are hunted by northern people for meat and eider down, said Grant Gilchrist of Environment Canada’s wildlife centre on the Carleton campus.
The disease has existed across North America, but usually farther south. It may have arrived in poultry imported to Texas in the 1940s.
“We were working on the eider at this site since 1996, before the disease arrived, so we’re in a rare position scientifically to have survival and reproductive data from before and after,” he said. “It’s just good luck.
“It’s a new and emerging disease in the Canadian Arctic, which is quite worrisome.”
The disease does not harm humans or other mammals, but affects many birds, especially water fowl in tight groups — many birds nesting on one island, or in a small lake.
Carleton biologist Mark Forbes, a parasitic disease expert, said it’s too early to prevent the disease. But scientists want to tell northern people when an outbreak is expected.
It may turn out that measures such as cleaning up carcasses after an outbreak could slow the spread, but that’s still an unknown, he said.
Gilchrist said they can’t hope to cure avian cholera yet, but scientists are eager to learn as much as they can about the disease. Among the mysteries: The bacteria aren’t believed to survive an Arctic winter, but are migrating birds bringing it back from the south each spring?
The three-year project is funded by the Natural Sciences and Engineering Research Council. Other team members come from Windsor, Rimouski and Norway.

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