A third British national has suspected hantavirus on the remote island area of Tristan da Cunha, the UK Health Security Agency said. The other two Britons who were medically evacuated are improving, global health authorities said.

The UKHSA said there is now “an additional suspected case of a British national on Tristan da Cunha”. The patient remains on the remote South Atlantic island.

A British passenger, understood to be a 69-year-old man, was taken to South Africa on April 27 and is receiving care at a private health facility in Sandton, Johannesburg.

Another Briton, 56, was taken off the MV Hondius on Wednesday and flown to the Netherlands to receive specialist medical care.

The ship arrived in waters off Cape Verde on 3 May, with a number of British nationals on board. UKHSA is working closely with the Foreign, Commonwealth and Development Office (FCDO), the World Health Organization (WHO), other UK public health agencies and international health partners to support the response.

It then left the shores of Cape Verde at 6.15pm UK time on Wednesday, Oceanwide Expeditions said, and is estimated to arrive at the port of Granadilla in Tenerife in the early hours of Sunday but this is subject to change.

The Foreign Office is arranging a charter flight so the remaining Britons on board the ship who are not displaying symptoms can be repatriated once they dock in Tenerife.

Dr Maria Van Kerkhove, from the World Health Organisation (WHO), said: “I am very happy to say the patient in South Africa is doing better, and the two patients in the Netherlands we hear are stable. So that is actually very good news.”

Some 19 British nationals were listed as passengers on the MV Hondius, which was sailing from Argentina to Cape Verde, with four British crew members.

UK health experts said British passengers on board will be asked to self-isolate in the UK for 45 days. According to the UKHSA, none of the British citizens on board are reporting symptoms but they are being closely monitored.

Hantaviruses are a group of viruses carried by rodents such as mice and rats, transmitted by their droppings and urine. Most hantaviruses do not spread between humans, although person-to-person transmission has happened with the Andes virus strain in rare cases. This is the strain of hantavirus that has been identified in the cruise ship outbreak.

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