Coronavirus clusters swell on both sides of the U.S.

Alarming clusters of the coronavirus swelled on both coasts of the U.S. on Tuesday, with 70 cases now tied to a biotech conference in Boston and infections turning up at 10 nursing homes in the hard-hit Seattle area.

Presidential candidates Bernie Sanders and Joe Biden abruptly canceled rallies because of worries about the virus, and New York’s governor announced he is sending the National Guard to scrub public places and deliver food in a New York City suburb that is at the center of the nation’s biggest known cluster of infections.

Massachusetts Gov. Charlie Baker declared a state of emergency as cases statewide jumped by 51 from the day before, to 92. Of that number, 70 are now connected to a meeting held last month by biotech company Biogen at a hotel in downtown Boston.

Baker said the state of emergency will give him greater authority to take such actions as shutting down large events, gaining access to buildings or stockpiling protective gear.

The moves came as the battle to stop the virus from spreading intensified. More schools and universities sent students home, while conferences and other events were canceled.

The United Nations announced it would close its New York headquarters to the public and suspend all tours.

The Coachella music festival that draws tens of thousands to the California desert near Palm Springs every April was postponed until October. And one of the biggest resort operators in Las Vegas, MGM Resorts International, said it would close buffets at all of its Las Vegas Strip casinos as a precaution.

A top federal health official pointed to Europe, rather than the virus’ point of origin in China, as the likely source for the infection’s continued spread to the U.S.

“Right now the epicenter — the new China — is Europe,” Robert Redfield, director of the Centers for Disease Control and Prevention, said on Capitol Hill. “And there’s a lot of people coming back and forth from Europe that are now starting to seed these communities.”

Authorities in Washington state reported two new deaths from the virus — a man and woman, both in their 80s, who were residents of a nursing home and a senior center. Of the 24 deaths in the state, 19 have been tied to a single nursing home, Life Care Center of Kirkland. But the state officials said they are now working with 10 nursing facilities where residents or workers have been tested positive.

Washington Gov. Jay Inslee announced new nursing-home rules that would limit visitors and subject health care workers to screening.

Similarly, in Kentucky, Gov.

Andy Beshear said state-run nursing homes will severely restrict visitors, with private operators strongly urged to follow suit. Six cases have been diagnosed in the state.

The decisions by both Democratic presidential candidates to call off rallies in Cleveland came as voters headed to the polls for a primary election in neighboring Michigan.

“We are heeding the public warnings from Ohio state officials, who have communicated concern about holding large, indoor events during the coronavirus outbreak,” Sanders campaign spokesman Mike Casca said in a statement.

“All future Bernie 2020 events will be evaluated on a case-bycase basis.”

New York Gov. Andrew Cuomo said three schools and other gathering places will be shut down for two weeks in a containment zone in New Rochelle, the epicenter of an outbreak of more than 100 cases.

JEFF CHIU — THE ASSOCIATED PRESS Passengers from the Grand Princess, a cruise ship carrying multiple people who have tested positive for COVID-19, exit a bus before boarding a chartered plane March 10 in Oakland. The passengers on the flight are going to San Antonio to be quarantined at Lackland Air Force Base.