Carnival Corp’s Princess Cruises has been hit by yet another potential Covid-19 coronavirus outbreak on board one of its US-based cruiseships.

Two passengers on a previous cruise on the 107,500-gt Grand Princess (built 1998) tested positive for the virus after disembarking from the ship in San Francisco on 21 February.

One man, a 71-year-old California resident, has since died, prompting California governor Gavin Newsom to declare a state of emergency.

He wants to make additional resources available and formalise emergency actions already underway as the number of cases rise in the state.

The passenger had underlying health conditions. His likely exposure occurred during a voyage that left on 10 February from San Francisco and took in Mexico, state officials said.

The patient tested positive on Tuesday and died on Wednesday.

Officials are trying to locate hundreds of other Californians who left the vessel in San Francisco.

Voyage cut short

The Grand Princess has cut short its 15-day voyage to Hawaii and Mexico and is returning to the city.

The US Centre for Disease Control (CDC) has instructed all passengers on the ship who had also sailed on the previous voyage to remain in their cabins until they are screened by its medical staff.

Princess Cruises said in a statement that it was working closely with the CDC and following its recommendations.

"The CDC is continuing to actively collect information and is collaborating with us to determine what, if any, actions need to be taken during the current Hawaii cruise and upon the ship's return to San Francisco. We have shared essential travel and health data with the CDC to facilitate their standard notification to the State and County health authorities in order to follow up with individuals who may have been exposed to the people who became ill," the company said.

“We are closely recording and monitoring all persons who have reported to the medical center with cold and flu symptoms during the voyage. As a precaution, we are also conducting additional enhanced environmental disinfection onboard in addition to our regular stringent cleaning and sanitation protocols.”

Princess has been especially hard hit by the coronavirus, with its Diamond Princess garnering international headlines after more than 700 passengers and crew on board its 115,900-gt Diamond Princess (built 2004) became infected during a prolonged quarantine period in Japan last month.

Last Sunday passengers on board its 77,400-gt cruiseship Sun Princess (built 1995) were met by angry protesters on the Indian Ocean island of Reunion, who prevented them from leaving the port by erecting blockades and pelting their tour buses with rocks and bottles.

MSC Opera passengers confined on board during Piraeus call

MSC Cruises has also been caught up in the coronavirus chaos after a previous passenger from its Mediterranean-based, 65,600-gt cruiseship MSC Opera (built 2004) tested positive for the coronavirus on Tuesday.

MSC Cruises said in a statement that the passenger, an Austrian national, disembarked from the ship in Genoa on 28 February, and returned home via northern Italy, an area that has been badly hit by the outbreak.

On Wednesday passengers on the ship's current voyage were held on board the ship when it called at Piraeus.

MSC said it informed the Greek health authorities about the reported case and requested that passengers, as a precautionary measure, remained on board while it sought guidance from the local authorities.

“We shared with the local health authorities the ship’s full medical records as well as the medical and travel history records of the former Austrian passenger.

“The Greek health authorities gave MSC Opera permission around 13:00 CET to sail from Piraeus, Greece, and continue its journey to its next scheduled port in Corfu, Greece. No additional health measures were required to be taken and the ship is currently sailing as planned.”

The vessel later docked as scheduled at the port of Corfu, Greece.

It 1,579 passengers and 723 crew onboard: a total of 2,302.

All were allowed to disembark, as planned, MSC said in a second statement.

"At no time have passengers or crew been quarantined and all were able to freely make use of the ship’s facilities and restaurants before it departed yesterday from Piraeus in Greece for Corfu," it added.

Health officials in Corfu earlier boarded the ship after it berthed, a common maritime practice, to review the ship’s full medical records and as was the case yesterday in Piraeus, deemed the vessel needed no further health measures beyond the ship’s existing strict preventative health measures, the company said.

Passengers and crew remained on board the ship on Wednesday for three hours while officials conducted a review of the vessel’s full medical records.

The check was to assess if any additional onboard health measures should be put in place.

There was no reported illness on Thursday, nor was there yesterday, among any of the 2,302 passengers and crew.