British Army medics have parachuted onto the remote Atlantic island of Tristan da Cunha to help a British national with suspected hantavirus.
The man left MV Hondius, the cruise ship hit by a deadly outbreak of the virus, in mid-April at Britain's most remote inhabited overseas territory, where he lives.
He first reported symptoms two weeks after leaving the vessel and is said be in a stable condition while isolating. Six cases of the virus have now been confirmed, including of two other Britons currently being treated off the ship.
Oxygen was also dropped from an RAF A400M on Saturday, with supplies at a "critical level" on the island, the Ministry of Defence (MoD) said.
Almost a month after the first death onboard the MV Hondius, the vessel has now arrived in Tenerife, where authorities are helping more than 100 people disembark to be repatriated.
Three people have died in the outbreak, including two who were confirmed to have had hantavirus.
Hantavirus is a group of viruses carried by rodents. Most hantaviruses do not pass from person to person, but the Andes strain, identified in a number of people who had been on the Dutch cruise ship, does.
The British man who lives on Tristan da Cunha disembarked on 14 April, the World Health Organization (WHO) said.
He reported having diarrhoea on 28 April and fever two days later. He is currently in a stable condition and in isolation.
A team of six paratroopers and two medical clinicians from 16 Air Assault Brigade parachuted on to Tristan da Cunha - an archipelago in the South Atlantic Ocean considered to be one of the world's most remote inhabited islands.
An RAF A400M transport aircraft, supported by an RAF Voyager, flew from RAF Brize Norton in Oxfordshire to Ascension Island, in the South Atlantic Ocean, before heading to Tristan da Cunha.
Two of the paratroopers jumped in tandem with an intensive care nurse and intensive care doctor, who will provide help to the island, which usually has a two-person medical team.
Tristan da Cunha has a population of 221 British citizens and no airstrip, meaning it can only be reached by boat. That was not an option in this case as the man was running out of oxygen supplies, according to Brig Ed Cartwright, who commands the 16 Air Assault Brigade and coordinated the parachute operation.
He told the BBC the parachutists faced a "really challenging, technical jump" due to high winds and the island being small. Average wind speeds over the island are often over 25mph (40km/h), the MoD said.
Brig Cartwright said the parachutists were dispatched from an aircraft about 5km (3.1 miles) over the South Atlantic Ocean, before turning in the wind and blowing backwards over the island and then carrying out a landing on its edge.
"The consequence of getting that wrong is that you end up in the Atlantic," he added.
It is the first time the UK military has parachuted in medical personnel to provide humanitarian support, according to the MoD.
They landed on the island's golf course, according to a local government website, with residents thanked for having "pulled out all the stops at short notice" to welcome the visitors.
Officials added that 3.3 tonnes (3,300 kg) of medical supplies were delivered for their hospital.
Brig Cartwright said the operation was not just about the man suspected of having hantavirus but also supporting the other people on the island, especially those who may have had contact with him.
Foreign Secretary Yvette Cooper said: "This extraordinary operation reflects our unwavering commitment to the people of our overseas territories and to British nationals, wherever they are.
"The safety and well-being of all members of the British family is our number one priority."
Minister for the Armed Forces Al Carns said there had been "incredibly challenging circumstances".
"I want to pay a huge tribute to our brave personnel for carrying out their task with the utmost professionalism and composure under pressure," he added.
Brig Cartwright said the parachuters would be taken off the island by ship. This is being carefully planned "in light of the medical situation", he said.
The WHO has confirmed that as well as the six confirmed cases, there are two with suspected hantavirus, which includes the British man on Tristan da Cunha.
The two British nationals with confirmed cases of the virus are being treated in the Netherlands and South Africa.
No other British nationals who remained on board the Hondius had reported symptoms but are being monitored, the UK Health Security Agency (UKHSA) said.
Meanwhile two Britons are voluntarily self-isolating at home in the UK, having disembarked the vessel at St Helena on 24 April before the first case of hantavirus was confirmed.
The remaining 22 British passengers are due to fly home from Tenerife on a charter flight.
They will be taken to Arrowe Park Hospital in Wirral, Merseyside, to isolate for up to 72 hours, and will then be asked to self-isolate for a further 42 days as a precaution, the UKHSA says.
The risk to the general public remains very low, the MoD said.
