Lucy, the Valley Zoo's Asian elephant, could die if she is moved because of problems with her breathing, a U.S. veterinarian told zoo officials after examining her Thursday. (CBC)

Moving Lucy the elephant from the Edmonton Valley Zoo could kill her, an American veterinarian told officials after he examined her last week.

Dr. James Oosterhuis, a lead researcher with the Colyer Institute in San Diego, examined Lucy on Thursday along with zoo veterinarian Milton Ness.

"Her [Lucy's] current respiratory problems preclude any thought of moving her, and, in fact, it would [be] life threatening for her to be placed under that kind of stress," Oosterhuis said in a letter to the zoo.

"It is my opinion that it would be unethical for any veterinarian to recommend moving her and, in fact, would be malpractice to sign a health certificate for her at this time."

Animal rights activists have been lobbying the city to move Lucy out of Edmonton, arguing that the city's cold climate and the fact that she is the only elephant in the zoo are detrimental to her health.

An endoscope was used during the examination to look at the elephant's trunk. It showed Lucy had severe swelling around the trunk and nose, making it hard for her to breathe through her trunk. While she can take in air through the mouth, stressful situations make it harder for her to breathe, according to a news release issued by the city.

"Given this third-party examination of Lucy and the stark recommendations that have resulted, the City of Edmonton and the Valley Zoo reconfirm that we will not consider moving Lucy to an American elephant sanctuary or, in fact, anywhere else," said city community services general manager Linda Cochrane at a news conference Monday.

"Let's be perfectly clear. Lucy will not be moved from the Valley Zoo. It's time to end the debate and let the dedicated staff at the zoo go on with the business of caring for the animals."

Moving Lucy would also contravene the Health of Animals Act, because her breathing problems makes it unsafe for the elephant to travel, Cochrane said.

Oosterhuis will continuing working with zoo veterinarian Ness to come up with a new treatment plan for Lucy's conditions, Cochrane said.

The city's announcement came a few days before a planned news conference in Edmonton Thursday by retired U.S. game show host and animal rights activist Bob Barker, who has been lobbying the city and the zoo to move Lucy to an elephant sanctuary in the U.S..

The news conference with Barker is the latest step in a campaign started by animal welfare group Zoocheck to have Lucy transferred out of the Edmonton zoo to an environment that is warmer and better suited to the highly sociable nature of an elephant.

On Monday, Zoocheck's Julie Woodyer said Oosterhuis' assessment does not settle the issue for them. She points to the case of Maggie, the elephant from the Alaska Zoo, who was moved from Anchorage to a sanctuary in California in 2007.

The zoo consulted 11 experts in making its decision to move Maggie. Oosterhuis was the only expert who said she shouldn't be moved, Woodyer said.

In February, Barker wrote a letter to city council urging the city to move Lucy. Another letter in favour of the move was sent in May by a group of Canadian authors, including Margaret Atwood, Michael Ondaatje, Nico Ricci, Jane Urquhart and Barbara Gowdy.

Last week, the People for the Ethical Treatment of Animals announced Canadian actor William Shatner had also written a letter to Edmonton Mayor Stephen Mandel lobbying for the move.

Lucy is the only elephant in a Canadian zoo that lives alone. She has been on her own since September 2007, when the Valley Zoo's other elephant, Samantha, was moved to be part of a breeding program at a zoo in North Carolina.

Lucy has lived most of her 34 years at the Valley Zoo.