Saturday, April 19, 2014

Lab tests show bald eagles' mysterious deaths caused by West Nile virus

By Amy Joi O'Donoghue, Deseret News

Published: Tue, Dec. 31 2:34 p.m. MST

 Bald eagles are perched at Farmington Bay Wildlife Management Area Friday, Dec. 20, 2013. The Utah Division of Wildlife Resources said Tuesday that lab results show 27 American bald eagles that have died in Utah were infected with West Nile virus. Officials believe they may have become infected while feeding on sickened eared grebes.

Bald eagles are perched at Farmington Bay Wildlife Management Area Friday, Dec. 20, 2013. The Utah Division of Wildlife Resources said Tuesday that lab results show 27 American bald eagles that have died in Utah were infected with West Nile virus. Officials believe they may have become infected while feeding on sickened eared grebes.

(Scott G Winterton, Deseret News)

SALT LAKE CITY — State wildlife officials hope the West Nile virus that has felled 27 American bald eagles in Utah will leave with the infected grebes that brought it here during their winter migration.

"The problem will leave with the grebes," said Mark Hadley, spokesman with the Utah Division of Wildlife Resources, adding that the eared grebes are slated to leave the state by mid-January.

Hadley said wildlife biologists suspect the eagles contracted the virus after eating infected eared grebes that died recently on Great Salt Lake.

Laboratory results announced Tuesday from testing performed at the Utah Veterinary Diagnostic Laboratory in Logan and the National Wildlife Health Center in Madison, Wis., ruled out many other possible causes of death, including avian influenza.

West Nile virus activity this time of year in Utah is a likely a first, according to JoDee Baker, an epidemiologist with the Utah Department of Health.

"In fact, we haven't ever in Utah seen something like this before," she said.

West Nile virus is spread to humans through the bite of infected mosquitoes, which are gone with the first hard freeze, Baker said.

Both Baker and Hadley stress there is no threat to public health, but people who come across any more infected eagles should contact the state wildlife agency as a precaution against other infections.

Dr. Bruce King, state veterinarian with the Utah Department of Agriculture and Food, said domestic livestock are safe, too, as well as horses and barnyard chickens.

Officials say they remain uncertain how the eagles got West Nile virus, as the disease typically affects birds during warmer months, when mosquitoes that carry the disease are active.

"(The grebes) might have gotten it farther north and flown in with it," Hadley said. "They can carry the virus within them for a long time before they develop symptoms and die."

Leslie McFarlane, the division's wildlife disease coordinator, said more than 2 million eared grebes stop at the Great Salt Lake during their winter migration. Almost every year, about 1 percent of the population that visits the lake dies from a bacterial disease called avian cholera.

“Every time grebes die, we send some of the dead birds to a laboratory for testing," McFarlane said. "Usually, avian cholera jumps out as the cause of death. This year, though, the initial laboratory results were not as conclusive. That led us to believe that something else might have killed the grebes this year.”

Although the mystery behind the 27 bald eagle deaths appears to have been solved, more deaths could continue, Hadley warned, until the grebes leave.

Email: amyjoi@deseretnews.com

Twitter: amyjoi16

Recommended
1. Cats
Somewhere in Time, UT,
Dec. 31, 2013

What's an eared grebe?

Those poor little things. I hope they can be saved.

2. Duckhunter
SLC, UT,
Dec. 31, 2013

Interesting. Based on the comments I've heard from the lib/greenie/whacko's I was positive it was because of Mormon's, global warming, hunters, lead, mercury, republican's, Gayle Ruzika, etc.

3. from but not of
Lindon, UT,
Dec. 31, 2013

Seals, sea lions, polar bears, sea stars, turtles, sockeye salmon, herring, anchovies and sardines on the West Coast of North America are all suffering mysterious diseases … which are killing many. Fukishima?

4. My2Cents
Taylorsville, UT,
Jan. 1, 2014

First responses is to annihilate the rodents in a way they die in their holes but we have to be careful so we don't violate any animal rights to trail and conviction before they can be food for the eagles.

Its apparent there is a push to save the grebe (mouse species) by animal activist. It violates the rodents right to medical care and treatment to cure them of the west Nile virus so the eagles can eat them. I'm surprised the activist aren't badgering our legislature to set up a wild eagle training program not to eat grebes or rabbits, it violates rights to a trial and conviction before they can be eaten.

It would go along way in saving many animal and dog and human species if the west Nile virus infected rodents could be exterminated by ovens or bullets or gas.

5. neolason
Roosevelt, UT,
Jan. 1, 2014

An Eared Grebe is a species of waterfowl
(Not a mouse)