Updated from 6:40 p.m. EST

A slew of American retail, technology and financial companies with branches in Asia are scrambling to protect employees -- and business operations -- from a mysterious respiratory illness that apparently originated in China.

The highly contagious disease, known as severe acute respiratory syndrome, or SARS, has spread in recent weeks to several countries, mostly in Asia, with Hong Kong being hit the hardest. On Tuesday, passengers on a

California-bound American Airlines flight from Tokyo complained of possible SARS symptoms, adding to the troubled industry's concerns. Later, news reports said the passengers didn't have the disease.

Still, a number of American tech companies have restricted travel to and from Asia, or have banned it outright, said a spokeswoman for the American Electronics Association.

Intel

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and

Motorola

(MOT)

are the only two American technology companies directly affected thus far.

"So far, we've heard no reports of other problems," said a spokeswoman for the 140-member Semiconductor Industry Association. "Transportation of goods has not been affected," she said. However, many semiconductor companies ship products via regularly scheduled airliners, so any disruption of passenger flights could create a problem.

Intel, which employs about 250 sales and marketing people in Hong Kong, asked some of its staff to work from home when it discovered that one of its employees lives in an apartment building believed to be a hot spot for the disease, said company spokesman Chuck Mulloy. The employee has developed symptoms of the potentially fatal disease, he said.

The partial quarantine will last until next week, Mulloy said, adding that the outbreak hasn't had a significant impact on business. As a precaution, Intel employees traveling to or from Asia must get approval from management at both ends of the trip. "Obviously we are monitoring the situation. We don't want to make the situation any worse," he said.

Intel has a much larger presence in the Philippines, Malaysia and mainland China, where it has assembly and testing facilities.

Meanwhile, 305 employees at a Motorola plant in Singapore were ordered to stay home after one of them was infected with SARS, according to a report in

The Wall Street Journal

. The plant was closed for part of the Thursday night shift, but reopened the next day.

Among retailers,

Nike

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receives between 85% and 90% of its footwear from four Asian countries: China, Indonesia, Vietnam and Thailand. But so far, the company has seen "little to no calculable impact" from SARS, according to Vada Manager, director of global issues management. "There have been no high rates of absenteeism. It's not affected any products in terms of slower delivery."

The company already had restricted travel because of security concerns. Yet with SARS adding to those worries, employees traveling to Asia must now have their trips approved by top management. "We're taking advantage of a lot more videoconferencing," said Manager. "There are more cars in the parking lots at night, with people who haven't been traveling trying to accommodate their Asian colleagues."

Retailer

Gap

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buys about 14% of its merchandise from China alone, including Hong Kong. (It doesn't offer a breakout for suppliers in the rest of Asia.) Spokesperson Claudia Hawkins said the company so far hasn't been impacted "either in terms of offices overseas or goods coming out of those countries at this point in time. But we are monitoring it quite closely."

Under the company's current travel policy, she said, "if employees do not feel comfortable

about traveling to Asia, they can have a conversation with their manager and postpone their trip."

Among banks,

HSBC

, the London-based bank with a big Asian operation, said it has moved a number of workers in Hong Kong to other locations.

Separately, a hedge fund manager said some overseas colleagues have expressed concern about how the disease could affect the operations of foreign funds.

But most financial firms with operations in Asia appear to be taking a wait-and-see attitude.

J.P. Morgan Chase

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and

Citigroup

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haven't taken any unusual precautions. Neither has

American Express

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.

Of course, until recently, no one had heard of SARS, so the situation is one that could quickly change in the coming weeks.

China's last tally, released more than a week ago, put total SARS cases in the country at 806, with 34 deaths, according to the

Associated Press

. The current worldwide total is more than 1,880 cases and at least 64 deaths, the

AP

said.

Meanwhile, the American Association of Cancer Research, which is holding its annual meeting in Toronto April 5 to 9, said the meeting is still on. The association said it has posted SARS-related material on its Web site for the roughly 15,000 people expected to attend. About 80 people in Toronto hospitals are possible SARS victims, according to the

Toronto Star

, which said six people in Canada have died of the disease.

Most of the infected in Toronto are health care workers, and two Toronto hospitals have shut their doors to incoming patients in an attempt to control the infection.

Two people -- a Wall Street hedge fund manager and an oncologist -- told

TheStreet

that they canceled plans to attend the cancer-research meeting due to SARS fears. The National Cancer Institute, which typically sends a large contingent to the meeting, doesn't have a formal travel ban in effect, according to a spokeswoman.

--

Matthew Goldstein contributed to this article.