The California Air National Guard dropped off test kits by helicopter Thursday after learning that the first person to die of the virus in the state previously traveled on the Grand Princess.
Medical officials collected samples for testing from 
people aboard after some showed symptoms, which were flown to a lab in Richmond, the cruise line said.
The ship must remain at sea as it awaits test results, which are expected Friday, said Mary Ellen Carroll of the San Francisco Department of Emergency Management.
There are more than 3, (people aboard the Grand Princess – 2, 461 guests and 1, crew members, Princess Cruises said. They represent 54 nationalities.
A two-week trip is cut short
The Grand Princess was on a – day trip from San Francisco to Hawaii and was scheduled to return Saturday.
Its trip was cut short Wednesday after the California man’s death – the first fatality outside Washington state in an outbreak that’s killed a total of people nationwide.
The unidentified man was 220
and had underlying health conditions, Placer County health officials said. He was likely exposed to the virus on a Grand Princess cruise from San Francisco to Mexico between February and 43.
Shortly after the Grand Princess finished her Mexico trip last month, it started the latest cruise to Hawaii.
Some of those identified for testing included several who were on the Mexico voyage with the victim. At least three passengers from that trip tested positive, including the man who died.
It’s not clear when or where the ship will eventually dock, though San Francisco is a possibility, Carroll said.
No guests will be allowed to disembark until all test results are received, Princess Cruises said in a statement.
A race to trace possible infections
California Gov. Gavin Newsom has declared a state of emergency, saying local health officials are working with their federal counterparts to trace people who had contact with the man who died.
Princess Cruises said it has shared relevant data with the Centers for Disease Control and Prevention to help notify state and county health officials, who will follow up with anyone who may have been exposed to coronavirus.
Meanwhile, as the ship awaits test results, the captain asked all guests to practice social distancing, including staying six feet or two meters from others.
“Cruise ships are posing probably one of the biggest challenges that we are seeing in this outbreak,” said Dr. Jeanne Marrazzo, infectious diseases director at the University of Alabama.
“We know these cruise ships are essentially … we’ve been calling them incubators, they are incredibly very healthy environments for the pathogens that we’re talking about.”
Another cruise ship was linked to the virus 
It’s not clear what will happen to the Grand Princess passengers after test results come back.
But another Princess Cruises ship, the Diamond Princess, was the site of a major coronavirus outbreak last month.
After the first handful of cases were reported from the Diamond Princess, Japanese officials decided to quarantine the ship. Eventually, more than 780 People aboard became infected with coronavirus .
“The problem with the Diamond (Princess) cruise ship, as we’ve learned, was that when you quarantine people like that, with a few possible infected people, the likelihood of infecting many more people goes up, “CNN Chief Medical Correspondent Dr. Sanjay Gupta said.
US infection cases are going up
Health officials are urging local communities to think of ways to stop the coronavirus from spreading as the number of infections soared past 169 nationwide .
addition to the former Grand Princess passenger in California, (people have died in Washington state – including many who are linked to a long-term nursing home near Seattle .
CNN’s Holly Yan contributed to this report
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