The outbreak of the coronavirus has forced some major North American companies to substantially alter their business and travel operations in China.

Starbucks, which this week reported earnings that beat expectations, had planned to raise its financial guidance, but the virus outbreak precluded the multinational coffee giant from doing that.

"Given the strength of our Q1 results, we had intended to raise certain aspects of our full-year financial outlook for fiscal 2020," CEO Kevin Johnson said on an earnings call Tuesday. "However, due to the dynamic situation unfolding with the coronavirus, we are not revising guidance at this time."

Starbucks has closed more than half of its 4,300 stores in China. The move came after the Seattle-based chain had a 3 percent same-store sales increase in China during the fiscal first quarter. Starbucks shares closed Wednesday in Nasdaq trading at $86.72, down $1.88 or 2.12 percent.

Starbucks' revenue from its China operations was $745 million in the quarter concluded Dec. 29, an increase of 13 percent over the year-ago figure.

Apple Inc, which on Tuesday reported record quarterly revenue of $91.8 billion, is restricting travel to China.

"We have limited travel to business-critical situations as of last week," CEO Tim Cook said. "The situation is emerging, and we're still gathering lots of data points and monitoring it very closely."

Apple has suppliers in the Wuhan area, center of the virus outbreak, but has alternatives, Cook said.

He said that factories outside Wuhan will not reopen after the Lunar New Year holiday until Feb 10, but Apple has built the delayed restart into its wider revenue forecast for the fiscal second quarter.

Apple has shut one store in China and reduced hours at others because of less activity, Cook said. Third-party stores that sell Apple products are also facing some closures.

Apple is "forecasting a stronger Q2 than analysts predicted, but the fact that the coronavirus is spreading in unpredictable ways in China, where Apple has most of its hardware built, could upset this optimistic forecast", said eMarketer principal analyst Yoram Wurmser.

The US Centers for Disease Control and Prevention has reported five confirmed coronavirus cases in the United States, with 68 tests coming back negative. The CDC has issued a Level 3 travel warning, urging American citizens to avoid all nonessential travel to China.

The virus has killed 170 people in China as of Thursday morning, according to official statistics.

Facebook was the first major American company to announce a travel suspension after a US government travel warning, saying it had asked employees to halt nonessential travel to the Chinese mainland and to work from home if they had traveled there.

Google said it will shut all of it offices on the Chinese mainland, as well as those in Hong Kong and Taiwan, according to the San Francisco Chronicle, while Amazon is temporarily restricting travel for its employees to and from both countries.

Air China is seeing reservations canceled to China, spokeswoman Jessie Wong in the San Francisco office told the Chronicle.

Wong told the paper that Air China, which has one daily flight to Beijing, didn't anticipate changing its flight schedule because the return flights from China are "very full".

Multinational banks — including BNP Paribas, Deutsche Bank, Goldman Sachs, Morgan Stanley, Credit Suisse and UBS — with operations in China and neighboring counties are postponing any nonessential travel to the region.

Employees returning from the Chinese mainland are being required to work from home for two weeks, according to Forbes.com, and can return once they are determined to be symptom-free.

Major airlines are canceling flights to help stop the spread of the novel virus and protect the safety of their pilots, flight attendants and others.

On Wednesday, American Airlines said it would suspend flights from Los Angeles to Shanghai and Beijing, as it has seen a drop in demand for travel.

Delta Air Lines, also on Wednesday, said it would cut weekly flights between the US and China from 42 to 21, starting Feb 6 and running through April 30.

United Airlines announced on Tuesday that it was suspending 24 flights between China and the US in the first week of February.

"Due to a significant decline in demand for travel to China, we are suspending some flights between our hub cities and Beijing, Hong Kong and Shanghai beginning Feb 1 through Feb 8," United said in a statement.

Jim Collins, in an article on TheStreet.com, said that electric-car companies Tesla and NIO will be pressured by the outbreak.

"Lost in Tesla shares' recent meteoric rise (NIO has had a very similar move) is that both companies need to make as many cars as possible in China to create cash flow. Selling them will be another matter, but at this point Elon Musk needs production at his Lingang factory to ramp as quickly as possible," Collins wrote.

He said NIO's cars are produced by JAC Motors in Anhui, closer to Wuhan, "and any production shutdown would threaten that company's fragile balance sheet".

Disney, Ford, General Motors, KFC, McDonald's and Pizza Hut are also among the major companies restricting their staffs from traveling to the region.

McDonald's has closed restaurants in five cities in Central China's Hubei province, where Wuhan is the capital.

A GM spokesman said the automaker has issued a global travel ban for China, with only "business-critical" travel allowed and only after a doctor's clearance, The New York Times reported. GM, along with Japanese automakers Honda and Nissan, has stopped production in Wuhan.

"Right now the impact is containable, but if it continues well past the Chinese New Year, it will have an impact on production as well as demand," Wedbush Securities analyst Dan Ives told CBS Money Watch. "There will be demand repercussions, especially with Wuhan on lockdown. With the population restricted, they won't be buying cars."

In Macao, cancellations at casinos and hotels jumped over the weekend as the virus' death toll rose, and the Chinese government extended travel restrictions.

"Cancellations soared across all of the properties we contacted," said Instinet analyst Harry Curtis, reported The Associated Press. "Pessimism rose on how long it could take for business to recover."

Major US casino hotel operators Wynn Resorts, Las Vegas Sands and MGM Resorts International have seen double-digit drops in their share prices since word of the virus spread midmonth.

Companies that make cleaning and disinfectant products, such as Clorox, Procter & Gamble and Kimberly-Clark, however, have seen their shares rise recently as a result of the virus.

Canadian companies are putting similar restrictions in place.

Air Canada said it was canceling some of its 33 weekly flights to China. Those customers affected will be notified and provided with travel alternatives. Shares of Air Canada have fallen 12 percent in the past week.

Imax, based in Mississauga, Ontario, Canada, has postponed the release of its Lunar New Year film lineup but said it had "every expectation that these films will be released in 2020 and that audience demand for these releases will remain high", according to The Toronto Star. The company has major expansion plans for China.

MKM Partners said in a research note that if the coronavirus outbreak lasts another month, "it is not unreasonable to project" a $200 million drop in revenue for Imax in the first quarter, the Star reported.

Ballard Power Systems, a clean-energy fuel cell maker based in British Columbia, has suspended all but essential travel. It will affect about 50 employees who travel from Canada to Ballard's operations in China, the Star reported.

Train-maker Bombardier Inc, based in Montreal, has 8,000 workers in China. The company said it is "monitoring the evolving situation" and asking staff to "strictly follow the travel and public health instructions issued by the Chinese authorities", according to The Canadian Press.

On Monday, the S&P/TSX stock composite index in Canada sustained its worst trading day in nearly four months.

Reuters contributed to this story.