Four new cases of coronavirus were confirmed in the UK on Sunday, as experts warned of an impending pandemic with parts of Italy in lockdown after a massive rise in the number of new infections there.
The new British patients had all been passengers on board the Diamond Princess cruise ship and were in quarantine in The Wirral when they fell ill, having returned from Japan on Saturday.
It emerged on Sunday that the patients had been tested while in Japan, but the results were not received until Sunday morning, by which point they were back in the UK.
They have now been transferred to specialist NHS infection centres.
Of the four people who tested positive for coronavirus, two patients are in the Royal Hallamshire Hospital in Sheffield, one is in the Royal Liverpool University Hospital and a fourth was taken to the Royal Victoria Infirmary in Newcastle, NHS England said.
Professor Keith Willett, NHS strategic incident director for coronavirus, said: "These specialist centres are well prepared to deal with cases and earlier this year, the Newcastle unit successfully treated and discharged two patients who had contracted the virus."
It brings the total number of UK cases to 13, and comes as the European threat from coronavirus dramatically increased, with four deaths in northern Italy following the diagnosis of more than 152 cases.
Eleven towns in the provinces of Lombardy and Veneto, which are popular with British holiday makers, were put into official lockdown, with Prime Minister Giuseppe Conte banning anyone from coming in and out without permission.
Armani held its Milan fashion week show behind closed doors on Sunday, and the Venice carnival has been cancelled in a bid to halt the spread of the illness. Until Friday, there were only three confirmed cases of the virus in Italy.
The Italian outbreak accompanied an explosion of cases in Iran and South Korea over the weekend, leading some experts to conclude the opportunity for containing coronavirus has now passed. Virologists now fear it is being spread by carriers who have minimal or no symptoms, making it much harder to track and contain.
Korean President Moon Jae-in placed his country on its highest level of alert after six people died and more than 600 people ill, while Iran reported eight deaths from 43 cases.
Dr Bharat Pankhania, senior clinical lecturer at Exeter University, who warned against quarantining passengers on board the Diamond Princess, said: “It is clear that all the important ingredients for a pandemic are now present.
“It’s better to be honest and say it.”
Meanwhile Professor Devi Sridhar, director of Edinburgh University’s global health governance programme, said: “The window of opportunity to contain the outbreak is closing very quickly.”
Dr Pankhania said that the Government should add Italy to its list of countries from which returnees should self-isolate if they develop viral symptoms.
Currently only nine Asian countries or territories are on the list.
Many British holidaymakers will have spent the half term break in the affected regions of Italy, but Public Health England is yet to update its guidance and the Foreign Office is understood not to be assisting anyone in the quarantined towns.
The emergence of four cases among Diamond Princess passengers who were allowed to return to the UK will raise questions about the quality of testing and decision making at Yokohama, Japan, where the ship is docked.
The ship has been one of the epicentres of the Coronavirus outbreak, with more than 600 passengers diagnosed and three fatalities.
Other British passengers, such as David and Sally Abel who were on the cruise for their 50th wedding anniversary and shared video updates of the quarantine online, were denied a flight home after developing symptoms.
The Abels are now in a Japanese hospital and have been diagnosed with pneumonia as well as coronavirus. Their family say they are desperate to return to the UK.
The new patients arrived at Boscombe Down military base in Wiltshire on Saturday in a group of 30 Britons and two Irish citizens.
The Department of Health said a "full infectious disease risk assessment" was done before Saturday's repatriation flight and that no-one who boarded the plane had displayed any symptoms of the virus.
Professor Chris Whitty, Chief Medical Officer for England said: “Four further patients in England have tested positive for COVID-19, bringing the total number of cases in the UK to thirteen.
“The virus was passed on in the Diamond Princess cruise ship and the patients are being transferred from Arrowe Park to specialist NHS infection centres.”
It came as 118 people were released from a coronavirus quarantine centre at Kents Hill Park in Milton Keynes, where they had spent 14 days since arriving on a repatriation flight from Wuhan, where the global outbreak started.
In China, premier Xi Jinping made a highly unusual admission by conceding “obvious shortcomings” in his regime’s handling of the crisis.
On Sunday night the global total of confirmed coronavirus cases stood at 78,914, with 2,467 deaths.
The growing spread of the virus across the world and within countries has sparked concern that it is being contracted from carriers with few or no symptoms, which would make it much harder to contain.
Dr Nathalie MacDermott, an infectious diseases expert at King’s College London, said: “The evolving situation in South Korea, Iran and Italy is very concerning.
“There has been the expectation that some countries might develop person to person transmission of SARS-COV2 following an imported case of infection from an affected country.
“What is concerning is the lack of clear contact with such an individual in initiating clusters in these three countries, and particularly in Iran and Italy.
“This suggests that there has potentially been transmission from an asymptomatic or minimally symptomatic individual who had not been tested for SARS-COV2.
“If such a situation is true, then the chance of significant transmission from asymptomatic or minimally symptomatic individuals occurring within these populations for a period of time before the first cases were identified increases.”
On Sunday night, Austria stopped all train services with Italy. Earlier it denied entry to a train from Italy amid concerns two passengers onboard had coronavirus.