(AP) — Passengers on a cruise ship off the California coast were instructed to stay in their cabins as they awaited test results Friday that could show whether the coronavirus is circulating among the more than 3,500 people aboard.

A military helicopter crew lowered test kits onto the 951-foot (290-meter) Grand Princess by rope and later retrieved them for analysis at a lab as the vessel lay at sea off San Francisco, under orders to keep its distance from shore. Princess Cruises said 45 people were selected for testing.

Authorities undertook the testing after a passenger on a previous voyage of the ship died of the coronavirus and at least six others on the same excursion became infected. Some passengers from that trip stayed aboard for the current voyage.

“The ship will not come on shore until we appropriately assess the passengers,” California Gov. Gavin Newsom said.

Depending on what they find, authorities could order a quarantine of all or some of those aboard.

Another Princess cruise ship, the Diamond Princess, was quarantined for two weeks in Yokohama, Japan, last month because of the virus, and ultimately about 700 of the 3,700 people aboard became infected in what experts pronounced a public-health failure, with the vessel essentially becoming a floating germ factory.

Meanwhile, the U.S. death toll from the coronavirus climbed to 14, with all but one victim in Washington state, while the number of infections swelled to over 200, scattered across at least 18 states. Pennsylvania and Indiana reported their first cases.

President Donald Trump signed an $8.3 billion measure to help public health agencies deal with crisis and spur development of vaccines and treatments.

On Wall Street, stocks went into another slide as fears mounted over the potential damage to the global economy from factory shutdowns, travel bans, quarantines and cancellations of events big and small.

Worldwide, the virus has infected more than 100,000 people and killed over 3,400, the vast majority of them in China. Most cases have been mild, and more than half of those infected have recovered.

Most of the dead in the U.S. were from suburban Seattle’s Life Care Center nursing home, now the subject of federal and state investigations that could lead to sanctions against it, including a possible takeover of its management. Washington state has the nation’s biggest concentration of cases, with at least 70.

Also, 30 medical professionals from the U.S. Public Health Service will arrive Saturday at the nursing home to help care for the patients and provide relief to the exhausted staff, said Dow Constantine, executive in charge of Seattle’s King County.

“We are grateful the cavalry is arriving. It will make rapid change in the conditions there,” he said. The nursing home was down to 69 residents after 15 were taken to the hospital in the preceding 24 hours, Constantine said.

The state of Washington is also setting up a command center dedicated to nursing homes, Gov. Jay Inslee said.

Some major businesses in the Seattle metropolitan area, including Microsoft and Amazon, which together employ more than 100,000 people in the region. have shut down operations or urged employees to work from home. The University of Washington called off classes at its three Seattle-area campuses for the next two weeks and will instead teach its 57,000 students online. And a comics convention next week in Seattle that was expected to draw about 100,000 people was canceled.

King County is buying a motel for $4 million to house patients and hopes to have the first of them in place within days at the 84-room EconoLodge in Kent, about 20 miles (32 km) from Seattle.

The ship off California was returning to San Francisco after visiting Hawaii.

A Sacramento-area man who sailed to Mexico on the Grand Princess in February later succumbed to the coronavirus. Others who were on that voyage have also tested positive, with four cases in Northern California and two in Canada, authorities said.

Princess Cruises said that no cases of the virus had been confirmed among those still on the ship. But three dozen passengers have had flu-like symptoms over the past two weeks or so, said Mary Ellen Carroll, executive director of San Francisco’s Department of Emergency Management.

Michele Smith, a Grand Princess passenger, posted video on Facebook of the helicopter that arrived at the ship. Another video showed a crew member wearing gloves and a mask and spraying and wiping a handrail.

“We have crews constantly cleaning our ship,” Smith was heard saying.

In a post, Smith said she and her husband were not quarantined and were told that only the people who had been on the Mexico voyage or those showing flu-like symptoms had to isolate themselves.

“Spirits are as high as can be under these circumstances. We are blessed to be healthy, comfortable and well-fed,” she wrote.

But a late-night statement Thursday from the cruise line said all guests were asked to stay in their rooms while results were awaited, in keeping with guidelines from the U.S. Centers for Disease Control and Prevention.