WASHINGTON (AP) -- A deadly bird flu virus will most likely slip into the United States through a pretty package: either majestic swans flying across the Bering Strait into Alaska or from smuggled exotic wildlife at one of the nation´s ports.

Its detection probably will depend on watching to see whether hundreds of birds die at once, Interior Department officials said Wednesday in an interview with The Associated Press, adding that it may not show up at all in 2006.

"From my perspective, I would say swans are the starting point because we found the disease already, or Europe has found them, in swans," said H. Dale Hall, director of the U.S. Fish and Wildlife Service.

The first 1,300 tissue samples taken in Alaska from migratory birds that could carry the H5N1 virus are due to arrive later this week at the U.S. Geological Survey laboratory in Madison, Wis. They come from a subsistence hunt by native Alaskans.

Among migrating birds, officials believe the disease will probably be transmitted from an Asian species to a North American one from the Pacific Flyway when both begin arriving in Alaska for the summer to nest. The Pacific flyway -- one of four bird highways in the sky over the United States -- stretches from Alaska and western Canada through the Western states to Mexico.

"Birds coming up that would fly in that flyway are the ones that would probably most likely mingle with the Australasian birds that have come up and may be carrying" H5N1, Hall said. "We´re working as if it could show up this year."

The Madison lab between now and next January will test 10,000 to 20,000 tissue samples for the ´H´ type of protein hemagglutinin. Testing for the ´N´ type of protein neuraminidase will be done by the Agriculture Department in Ames, Iowa. Nationally, 70,000 samples are expected to be tested.

Only after both phases of testing will Bush administration officials announce whether the highly pathogenic H5N1 has arrived in the United States. The virus has spread from Asia to Africa and Europe, killing at least 124 people.

If an H5N1 strain shows, officials will then have to determine whether it is a highly pathogenic variety capable of causing a large kill of at least 500 or more birds.

Typically, three to 12 die-offs of more than 500 birds occur each year. There have been two this year already, from bird cholera at Klamath Basin in Oregon and California and parasites in the Mississippi River between Wisconsin and Illinois, Hall said.

He added, however, that global trade in pets, illegal wildlife and animal parts could prove to be the more likely route for the deadly virus reaching the United States.

"I am more concerned about the illegal smuggling and the bringing-in illegally of birds into this country," he said. "And the reason is an endangered species, or even birds people are not supposed to have because they´re from another country bring very high dollars in."

Hall and Patrick Leahy, director of the U.S. Geological Survey, which is conducting the initial round of tests for presence of the virus, said their concerns about the virus will ease sometime between October and December if it hasn´t shown up.

"We may dodge the bullet this year, but the sampling will continue," Leahy said, explaining the entire effort would begin anew next spring.

Leahy said a variation of influenza in birds, H5N2, was found last year in two of 100 birds sampled in North Dakota.

The first samples of the two ducks came back positive for the deadly bird flu strain, but more analysis found they were infected with one of a number of duck viruses and "there was nothing to be concerned about," said Ted Gutzke, project leader at North Dakota´s J. Clark Salyer National Wildlife Refuge.

It isn´t clear yet which birds will be show symptoms of the disease or just be a carrier like a Typhoid Mary, Leahy said. The USGS is looking at how the virus behaves in different wildlife species, he said.

Meanwhile, the White House was closely monitoring a family cluster of bird flu cases most likely transmitted from human to human in Indonesia. Seven of eight family members died, but there wasn´t reason yet to fear a pandemic, said the World Health Organization in Geneva.

"They´re still trying to investigate the possibilities it´s human-to-human contact, whether this is the sort of contact that might lead to a pandemic," said Tony Snow, President Bush´s press secretary.

Hall said the Fish and Wildlife Service hopes to collect tissue samples or feces from 27 species of migratory waterfowl and shorebirds that could have contracted virus -- directly or indirectly -- from ducks in China or other sources. It also is collecting water samples from where birds defecate.

No one knows whether the virus will reach the United States or develop into a strain of deadly flu that can be transmitted easily by humans. Until that happens, Interior officials say they won´t become alarmed.

"Our reaction until there´s evidence that it has recombined or has mutated would be to treat it as we do other wildlife diseases -- make sure people know it´s there," Hall said. "We have bird die-offs every year."

In the meantime, Hall advised anyone who comes across a dead bird not to handle it. Game birds should be cooked thoroughly and hunters should keep sanitation in mind in handling, cleaning and deboning them, he said.