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.