BBCThree people have died after a suspected hantavirus outbreak on a cruise ship sailing in the Atlantic Ocean, the World Health Organization (WHO) has told the BBC.
One case of hantavirus has been confirmed, with five more suspected cases under investigation, it said. One British national aged 69 is in intensive care in Johannesburg, South Africa.
The UK Foreign Office told the BBC it was monitoring reports closely, and was ready to support British nationals.
The outbreak was reported aboard the MV Hondius cruise ship, which was travelling from Argentina to Cape Verde.
Hantavirus infections are usually linked to environmental exposure, such as contact with urine or faeces from infected rodents, but in rare cases can spread between people, leading to severe respiratory illness.
Foster Mohale, a spokesperson for South Africa's health ministry, earlier told the BBC that at least two people had died.
The MV Hondius is run by tour company Oceanwide Expeditions.
According to an itinerary on its website, MV Hondius departed from Ushuaia in Argentina on 20 March and was expected to complete its journey on 4 May in Cape Verde.
It is described as a 107.6m (353ft) polar cruise ship, with space for 170 passengers in 80 cabins, along with 57 crew members, 13 guides and one doctor.
South African authorities told the BBC the first person to show virus symptoms was a 70-year-old passenger who died on board. His body is now on the island of Saint Helena, a British territory in the South Atlantic.
His 69-year-old wife also became ill on board and was evacuated to South Africa, where she died in a Johannesburg hospital.
The husband and wife were a Dutch couple, AFP news agency reported citing a source close to the case.
Speaking anonymously, the source told AFP the third fatality was still on board the ship, and discussions were under way to decide whether two other sick passengers should be placed in isolation in hospital in Cape Verde.
The ship would then reportedly continue to Spain's Canary Islands.
The WHO said it was helping co-ordinate between member states and the ship's operators for the medical evacuation of two symptomatic passengers, as well as a full public health risk assessment and support for those still on board.
