Health officials won't identify him, but reports say he is in his 30's and had traveled near Wuhan, China earlier this month before returning home. He landed at Seattle's Sea-Tac Airport last Wednesday and developed symptoms a few days later.
RELATED: 1st Coronavirus US case confirmed by CDC; virus has killed 6 in China
He sought medical care on Sunday and is said to be in stable condition.
U.S. health specialists will be able to study the coronavirus closely as the other confirmed cases are in five Asian countries -- China, Thailand, Japan, Taiwan and South Korea.
In a conference call disclosing details of this case, the CDC made an ominous warning. It expects additional cases in the United States and globally.
The @CDCgov expects more cases of new #coronavirus in the U.S. & globally. @StanfordMed infectious disease expert Dr. Yvonne Maldonado (in photo) says with confirmed U.S. case "there should be a healthy degree of concern, but I wouldn't panic." @abc7newsbayarea #abc7now pic.twitter.com/z7gF4gN8S3— David Louie (@abc7david) January 22, 2020
Dr. Yvonne Maldonado, an infectious disease researcher at Stanford Medicine, says a containment strategy is no doubt underway.
"They're probably already contacting the people who flew on that plane and had any kind of close contact with that particular person," she told ABC7 News.
The specific coronavirus wth its origin in Wuhan, China is so new, it's not known how soon symptoms develop after initial exposure. The killer virus has symptoms similar to the flu, so doctors and nurses will need to ask about travel and links to China to pinpoint that strain.
The CDC also has a test, which it said it plans to share with local and state health agencies to accelerate confirmation of cases.
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"I think there should be a healthy degree of concern, but I wouldn't panic," said Dr. Maldonado. "I think we have contained these epidemics in the past."
A special committe of the World Health Organization meets Wednesday in Geneva, Switzerland to determine if a global emergency exists. Such a declaration was made with past outbreaks of SARS, MERS, ebola, zika and swine flu.
ABC7 News was in Hong Kong in 2003 during the SARS epidemic that took more than 600 lives and paralyzed the economy. The lessons learned then are still applicable today, including aggressive action to contain the outbreak.
ABC News correspondent Bob Woodruff met a San Francisco nurse at Hong Kong's airport Monday, who was making a hasty retreat home to avoid the new coronavirus.
"Oh, yes, of course, that's why I'm going home," said Dan Clowry. "I want to get home as soon as I can."
There is no vaccine for the new coronavirus. For now, each nation is on its own to contain it.
"Every country will have its own measures," said Dr. Maldonado. "We can't control that. What we can control is what happens here in this country. This is what they're (the CDC) trained to do, and they're very good at it."