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SAN FRANCISCO (KGO) -- The U.S. Centers for Disease Control and Prevention is investigating a "small cluster" of novel coronavirus cases that originated on board a cruise ship that traveled from San Francisco to Mexico last month.According to the San Francisco and CDC officials, three people who were on board the Grand Princess Voyage cruise ship from Feb. 11 to Feb. 21 tested presumptive positive for the virus.Two patients are from Placer and Sonoma counties.Placer County officials confirmed Wednesday the 71-year-old male patient on board the ship died, marking the first coronavirus-related death in California."We extend our deepest condolences to the loved ones of this patient," said Placer County Health Officer Dr. Aimee Sisson. "While we have expected more cases, this death is an unfortunate milestone in our efforts to fight this disease and one that we never wanted to see.Before his death, the man was in isolation at a Kaiser hospital in Roseville.According to Placer County health officials, the man arrived at the hospital Feb. 27 and came into contact with 10 Kaiser healthcare workers and five emergency respondersThose individuals are now under quarantine but are not showing symptoms of the virus, the county said.Gov. Gavin Newsom issued a statement Wednesday regarding the man's death in Placer County, offering sympathy to the person's family."Jennifer and I extend our deepest condolences to the family and loved ones affected by this death in Placer County," the governor said. "The state is working with federal officials to follow up on contact tracing of individuals that may have been exposed to provide treatment and protect public health."Later in the day Wednesday, Newsom declared a state of emergency in response to the coronavirus spread and first death in California."This emergency proclamation will help the state further prepare our communities and our health care system in the event it spreads more broadly," Newsom said in a statement to ABC7 News.As of Wednesday, the Grand Princess cruise ship was in route to Ensenada, Mexico -- but because of coronavirus concerns, the ship is now heading back to San Francisco.Newsom said the ship will not be allowed to dock at the port in San Francisco until those on board are tested for the virus.A passenger onboard the cruise spoke with ABC7 via Facebook chat on Wednesday and shared her concerns over the situation."I'm concerned that we may not get off by Saturday when we have a flight out on Sunday," said cruise passenger Teresa Johnson.She told ABC7 about some of the precautions the cruise line is taking with passengers on board."They're making sure we're washing our hands regularly, using hand sanitizer, using all kinds of safety measures," said Johnson.She explained that the kitchen staff was handing out silverware with tongs.Johnson and her husband boarded the ship Feb. 21 for a Hawaiian cruise.She says some people on her cruise, stayed over from the previous Mexico cruise."(They're) asking anyone who was on the first cruise who's still on board to stay in their cabins until they get checked by the ship's doctors," Johnson said.In light of the coronavirus concerns on the ship, Gov. Newsom said testing kits are now being flown to the cruise.The testing will be expedited in Richmond, Newsom said.The ship was originally expected to return to San Francisco Thursday, but the cruise line now says the date and time are to be determined.According to the governor, about 2,500 people were on board the Feb. 11 cruise and half of those passengers were from California.In a statement Thursday, the City of San Francisco reiterated it is prepared to support federal health officials' efforts in caring for the cruise ship passengers. A letter was sent to guests on board the cruise ship, telling them to stay in their rooms until they have been "contacted and cleared" by cruise medical staff.Those who traveled on the Feb. 11 Grand Princess Voyage are asked to contact their doctor if they've experienced any symptoms since returning home from the cruise -- including fever, chills or a cough.Heidi Wolter, who lives in Napa County, was on the first leg of the cruise that sailed from San Francisco to Mexico. She has been in self-quarantine at her home since Monday, after learning about the passengers aboard her cruise tested positive to COVID-19.Wolter says Princess Cruises did a "great job" to take the necessary precautions to keep passengers safe. However, she hopes that passengers are also kept up-to-date, especially since most of the passengers are seniors, a group vulnerable to the coronavirus."It's a lot of stress. It is a lot of stuff to manage for a population that this virus seems to attack viciously," says Wolter. "So my concern is for (the cruise line to) not minimize (passenger) exposure because it is proven fact that they have been potentially exposed."