The number of newly identified COVID-19 cases in the U.S. soared over the weekend, and now cities like Los Angeles and New York City and states including Illinois and Ohio are moving into lockdown mode, with schools, bars, restaurants, and other large gathering spaces shutting down for weeks at a time.

This is the “defining health crisis of our time,” Dr. Tedros Adhanom Ghebreyesus, director-general of the World Health Organization (WHO), told reporters on Monday.

There are now 4,138 cases of COVID-19 in the U.S. and at least 71 people have died, according to the most recent data from the Johns Hopkins Whiting School of Engineering’s Centers for Systems Science and Engineering.

This includes global retailers that already implemented store closures in China and parts of Western Europe as the virus has moved around the world over the last eight weeks. Columbia Sportswear Co. COLM, -1.44% , Levi Strauss & Co. LEVI, -5.15% , Nike Inc. NKE, -1.46% , and VF Corp. VFC, -3.29% are just a handful of the retailers to close their stores in various parts of North America.

“Our sense is that the plan is to watch the trends in coming weeks…with high likelihood that closures will be extended as coronavirus cases rise,” Credit Suisse analysts wrote Monday morning. “The sudden and complete stoppage of retail operations will clearly have a dramatically negative effect on most retailers’ near-term earnings and cash flows. The bigger picture is: it’s impossible to know how long these stoppages could continue…with many municipalities signaling potential for extended shutdowns.”

Apple Inc. AAPL, -3.17% , which announced it had closed all retail stores outside of China until March 27, last week had already put into place some distancing measures in its stores, including limiting the number of customers and having all of its employees wear latex gloves at its store in Brooklyn.

One lesson the company learned from its experience with China’s outbreak of the novel coronavirus is “that the most effective way to minimize risk of the virus’s transmission is to reduce density and maximize social distance,” CEO Tim Cook said in a statement Friday. All 52 of its stores in China have now reopened.

Walmart Inc. WMT, -1.02% has cut operating hours at its stores and Neighborhood Markets until further notice. Those stores are usually open 24 hours a day but will now be open from 6 a.m. to 11 p.m., to allow time to restock shelves and clean and sanitize the stores. At the same time, Amazon.com Inc. AMZ, -1.94% said it is running out of household staples as people stock up on paper goods and pantry items while they are at home.

“We’re also working to ensure that no one artificially raises prices on basic need products during this pandemic and have blocked or removed tens of thousands of items, in line with our long-standing policy,” the company wrote in the blog post.

Worldwide, there are now 179,073 cases of COVID-19 and at least 7,074 people have died. The ongoing outbreaks in several countries in Western European countries and the U.S. are fueling the growth of cases of the novel coronavirus, which was first detected in December in China’s Hubei Province. More than 78,000 people have recovered.

In Italy, there are now 27,980 cases and 2,158 deaths; Spain, 9,428 cases and 335 deaths; Germany, 7,174 cases and 14 deaths; France, 5,397 cases and 127 deaths; and Switzerland, 2,200 cases and 14 deaths. The other two national outbreaks of concerns are in South Korea (8,236 cases and 75 deaths) and Iran (14,991 cases and 853 deaths).

Tedros said for the first time the number of cases in the rest of the world has exceeded those in China.

Here’s how companies are being impacted by COVID-19:

• Airline stocks tumbled toward fresh lows in premarket trading Monday, after the U.S. expanded its travel ban to the U.K. and Ireland and amid growing fears of a global recession as COVID-19 spreads. United Airlines Holdings Inc.’s UAL, -3.61% stock fell 17.7%, after the air carrier said late Sunday that it expects March revenue to be $1.5 billion lower than a year ago. Shares of American Airlines Group Inc. AAL, -3.22% plunged 20.5%, Delta Air Lines Inc. DAL, -3.29% dropped 15.1%, Southwest Airlines Co. LUV, -1.41% lost 12.8% and JetBlue Airways Corp. JBLU, -2.01% shed 13.4%.

• A number of casino operators have said they would shut down temporarily, including Penn National Gaming Inc.’s PENN, -3.28% Zia Park Casino Hotel & Racetrack in New Mexico, MGM Resorts International’s MGM, -2.22% Las Vegas casinos as well as its MGM National Harbor casino in Maryland, and Wynn Resorts Ltd.’s WYNN, -2.01% Wynn Las Vegas and Encore casino and hotel.

Additional reporting by Tomi Kilgore

Read more of MarketWatch’s COVID-19 coverage:

‘It’s going to be daunting’: U.K. considers herd-immunity approach — allowing more people to contract coronavirus

Playdates are out, schedules are in — what experts say kids should and shouldn’t do as the coronavirus outbreak closes schools

How to make sure your loved one is protected from coronavirus if they’re in a nursing home