US Domestic News Roundup: Biden, now backed by Booker; Confirmed coronavirus may force Americans to avoid crowds and more

Following is a summary of current US domestic news briefs. On the trail:

Biden, now backed by Booker, and Sanders vie for Michigan ahead of Tuesday's vote

Democratic presidential contender Joe Biden will focus campaign efforts on Monday on Michigan, the biggest prize of the six states to hold contests this week, where a win could give him an insurmountable lead. A victory for Vermont senator Bernie Sanders in Michigan, which offers 125 of the 1,991 delegates needed to secure the nomination, is critical for him to recapture momentum in the bid to face Republican Donald Trump in November's general election.

Confirmed coronavirus may force Americans to avoid crowds and cancel cruises; U.S. cases near 550

Older Americans, especially those with chronic medical concerns, should probably avoid big social gatherings and airline flights, given the rapid spread of coronavirus, a top U.S. health official said on Sunday, as investors braced for another volatile week in financial markets. Anthony Fauci, the head of the infectious diseases unit at the National Institutes of Health, also said on NBC's "Meet the Press" that after initial missteps distributing diagnostic tests, there should be 400,000 more kits available by Monday and 4 million by the end of the week.

Oregon declares emergency as coronavirus cases double to 14

Oregon Governor Kate Brown declared a 60-day state of emergency on Sunday as coronavirus cases in the state doubled to 14. "We will do everything in our power to keep Oregonians safe," Brown said at a news conference. U.S. Senator Cruz self quarantines after contact with coronavirus carrier Two U.S. Republican lawmakers, Senator Ted Cruz and Rep. Paul Gosar, said on Sunday they will quarantine themselves after contact at a late February gathering of conservatives with someone who has since tested positive for coronavirus. Cruz and Gosar were among the U.S. politicians and activists who gathered just outside Washington Feb. 26-29 for the annual Conservative Political Action Conference (CPAC), which met this year under the theme "America vs. Socialism."

No hugs, handshakes as U.S. churches take new precautions against coronavirus

With a wide smile and arms outstretched, but quickly dropped into double elbow bumps, James Harper warmly greets fellow congregants at Our Lady of Lourdes Catholic Church on Sunday in Atlanta's Old Fourth Ward neighborhood. "We're all right here," said Harper, 51, a salesman. "Normally it's nothing but deep hugs. But it's a different day now."

Grand Princess cruise ship passengers bound for coronavirus quarantine in California, elsewhere

An ocean liner barred from returning to port in San Francisco due to a coronavirus outbreak onboard will dock briefly at a nearby terminal in Oakland, where passengers will be unloaded and sent on to medical and quarantine sites elsewhere, officials said on Sunday. The cruise ship Grand Princess, whose guests have been largely confined to their staterooms since Thursday, is due to arrive at the Port of Oakland on Monday to begin immediately disgorging its 2,400 passengers, California Governor Gavin Newsom told a news conference.

Twitter labels edited clip of Biden retweeted by Trump as manipulated media

Twitter Inc on Sunday used its new "manipulated media" label for the first time on a video clip of U.S. Democratic presidential candidate Joe Biden that was retweeted by President Donald Trump. The video, which was posted on Saturday by White House social media director Dan Scavino, showed Biden stumbling on a speech in Kansas City, Missouri, in which he said the words "Excuse me. We can only re-elect Donald Trump."

Trump's focus on coronavirus numbers could backfire, health experts say

President Donald Trump loves numbers, and the ones he believes illustrate his accomplishments - an unemployment rate at a 50-year-low and stock markets at record highs - have become touchstones in his speeches, rallies, and Twitter missives. The numbers in the coronavirus outbreak in the United States are increasingly not going his way, but that has not stopped him from portraying them largely as a sign of success. NASA Ames tells employees to work from home after one tests positive for coronavirus

NASA's Ames Research Center in California said late on Sunday it would make its employees work from home until further notice after one tested positive for coronavirus. The agency said it received confirmation on Sunday of an employee testing positive for COVID-19.

Top U.S. congressional Democrats urge worker protections during coronavirus outbreak

The two top U.S. congressional Democrats urged President Donald Trump on Sunday to act quicker to protect workers affected by the deadly coronavirus, including free testing for the virus and paid sick leave for those under quarantine orders or caring for children kept home by school closures. "President Trump continues to manufacture needless chaos within his administration and it is hampering the government's response to the coronavirus outbreak," House of Representatives Speaker Nancy Pelosi and Senate Democratic leader Chuck Schumer said in a statement.