A British tourist who boarded a flight only a few rows away from a woman who later died from hantavirus has been detained and quarantined while on holiday in Italy.

The holidaymaker and his companion - who was not even on the flight in question - were apprehended outside a bar on Tuesday night and taken to Sacco Hospital in Milan by the authorities.

Despite testing negative for the virus and showing no symptoms, they have both been placed in quarantine until June 6, completing the 42-day isolation period required by the ministry of health.

The British citizen had boarded the same Airlink flight from Saint Helena to Johannesburg as MV Hondius passenger Mirjam Schilperoord, 69, who later died.

She was the wife of Dutch ornithologist Leo Schilperoord, 70, who is believed to be 'patient zero'. The couple became sick after visiting a landfill site in Argentina to watch birds. 

The UK government notified Italian authorities about the British tourist, who had visited various countries including Amsterdam before arriving in Milan.

Because he had no private accommodation and was staying in a B&B, he will have to endure the whole of his quarantine in a single room in the Infectious Diseases ward of the hospital.

It comes as Italian authorities are waiting to determine whether a 25-year-old man, who boarded a KLM flight with Mrs Schilperoord - from Johannesburg to Amsterdam - will test positive for the virus.

Local authorities are analysing the Calabrian man's biological samples at Spallanzani Hospital in Rome, to determine whether he has the lethal disease.

He is in voluntary isolation at home while he waits for the results. 

Health officials also requested samples from an ​Argentine tourist, who had left an endemic area back home on April 30 and traveled to Italy on a Buenos Aires-Rome flight before later going to Sicily.

There, she was hospitalised ​with pneumonia.

Ten Britons from South Atlantic islands linked to the cruise ship outbreak will be brought to the UK in case they develop the illness, officials have revealed.

The group, who are residents of the UK overseas territories of Saint Helena and Ascension Island, are being flown to Britain to complete their self-isolation.

All those involved are British and are understood to include people who left the cruise ship in Saint Helena, plus medical staff who have been in contact with them.

The UK Health Security Agency (UKHSA) said the total included four individuals in Saint Helena who were on the cruise ship and six close contacts on Ascension Island.

None are symptomatic and their final destination in Britain is unknown, but the move was described as 'precautionary to support communities in UK overseas territories'.

Once in Britain they will get access to NHS infectious disease specialists should they become ill, and the UKHSA said it will 'set out where they will isolate in due course'.

It comes as 20 British nationals from the MV Hondius, together with a German who is a UK resident, and a Japanese passenger, who have been isolating at Arrowe Park Hospital on the Wirral in Merseyside prepare to leave the facility.

They were taken there on Sunday night after the ship docked in Tenerife, for a three-day isolation and assessment period. They will isolate for another 42 days at home.

The UKHSA said of this group: 'Public health and clinical specialists have assessed each passenger's individual circumstances, and, where it is safe and possible, tailored support packages will be provided to enable people to isolate at home.

'Health protection teams across the UK will continue to monitor and support everyone after they leave the facility, with daily contact throughout the isolation period to ensure they can isolate safely.'

The statement also said a 'small number of individuals who have been isolating at home or elsewhere in England' will also be assessed at the hospital.

Previously, it was reported that two Britons who returned to the UK from the ship early have been isolating at home. They contacted officials after hearing about the outbreak of hantavirus.

It is understood that neither of these people have developed hantavirus symptoms but are going to stay at Arrowe Park while they continue to isolate.

Professor Robin May, chief scientific officer at UKHSA, said: 'We are grateful to the passengers for their cooperation and patience in what we appreciate has been a very unsettling period for all involved.

'As this first assessment period concludes, our priority remains to ensure everyone is safe and well supported, wherever they complete their isolation. Our teams will continue to be there for all of the affected individuals every step of the way.'

Earlier, a statement from the Ascension Island Government said a 'small number of individuals currently on St Helena who travelled on the vessel have been assessed as higher risk'.

It said: 'While the likelihood of illness remains low, UKHSA has advised that they should be the subject of pre-emptive relocation to the UK to complete their self-isolation. This is being arranged and they will be fully supported on arrival.'

One British man with hantavirus is still being cared for in Johannesburg and is thought to be improving, while another is in the Netherlands.

Another British national has hantavirus and is isolating where he lives on the remote island of Tristan da Cunha.

Separately, the head of the World Health Organisation (WHO) told a briefing yesterday that some passengers on the cruise ship had been 'facing mental breakdown'.

Dr Tedros Adhanom Ghebreyesus said it would have been 'inhumane' to leave people on board the ship rather than letting it dock in Tenerife, from where people were repatriated to their home countries.

He said there was a need for kindness and compassion towards those involved.

He said: 'Almost 150 people from 23 countries were on this ship for weeks, in what must have been a very frightening situation. Some of the passengers were facing mental breakdown. They have the right to be treated with dignity and compassion.

'There were some people around the world calling for the passengers to be contained on the ship for the full quarantine period. Our view was that would have been inhumane, and unnecessary. Yesterday during our press conference I called it even cruel to suggest that.

'We were convinced it was possible to disembark these passengers in a way that was safe for them and the people of Tenerife, and that was respectful of the human rights of the passengers and crew.'

The leader praised Spain's prime minister, Pedro Sanchez, for allowing the ship to dock in the Canaries. 

He added: 'I thank Prime Minister Sanchez not only for meeting Spain's legal duty under international law, but also for exercising his moral duty to show solidarity with, and compassion and kindness for the passengers on the ship.'

So far, 11 hantavirus cases have been reported among people on the cruise, including three deaths.

Nine of the 11 cases are confirmed, with two more probable cases.

'At the moment, there is no sign that we are seeing the start of a larger outbreak,' Dr Adhanom Ghebreyesus told the briefing, adding: 'And given the long incubation period of the virus, it's possible we might see more cases in the coming weeks.'

In a video message on Monday, the ship's captain Mr Dobrogowski thanked passengers and crew and said 'the past few weeks have been extremely challenging to us all'.

He added: 'What touched me the most, what moved me the most, was your patience, your discipline, and also (the) kindness that you showed to each other throughout.'

Meanwhile, a French woman who tested positive for hantavirus is in intensive care in a stable condition at a Paris hospital.

One of 18 evacuated passengers flown to the US has also tested positive but has no symptoms, while another had mild symptoms.

Spain's health ministry said one Spaniard who is quarantining in Madrid has also provisionally tested positive for hantavirus.