A third British national has been diagnosed with suspected hantavirus linked to a cruise ship outbreak, health officials have said.

The UK Health Security Agency (UKHSA) had already confirmed two cases among British nationals, who are in hospitals in the Netherlands and South Africa. It said a third had been reported on the south Atlantic island of Tristan da Cunha, where the patient remains.

The outbreak linked to the cruise ship MV Hondius has killed three people and the World Health Organization has warned more hantavirus cases could emerge, though officials said they expected the outbreak to be limited if precautions were taken.

The fate of the Hondius has prompted international alarm and a scramble to trace the outbreak of the potentially deadly human-to-human strain.

The UKHSA said none of the British citizens still onboard the ship, which is travelling to Tenerife, were reporting symptoms, but they are being closely monitored.

The islands of St Helena, Ascension and Tristan da Cunha all lie in the south Atlantic Ocean, midway between Africa and South America. A total of 29 people left the Hondius – including seven Britons – when it docked in St Helena on 24 April, including a Dutch woman who became unwell during onward travel and died.

The ship is expected to dock in Tenerife on Sunday, according to the latest updates from the Spanish health ministry.

The UKHSA said: “UK government staff will be on the ground ready to support the British nationals disembarking. British passengers and ship crew not displaying any symptoms of hantavirus will be escorted by UK government staff to an airport and given free passage back to the UK.”

It said Foreign Office officials and UKHSA teams would continue to support passengers, with a dedicated repatriation flight being organised for them and crew.

The organisation added: “UKHSA is working with partners to ensure the flight operates under strict infection control measures. Public health and infectious disease specialists from UKHSA and the NHS will be onboard to monitor British nationals whilst on the flight, to ensure that preventative measures are in place and to provide any care in the unlikely event that any passengers become unwell on the flight.”

All British passengers and crew from the ship are being asked to isolate for 45 days after returning to the UK, with close monitoring by health officials. The UKHSA said: “Follow-up is already under way for individuals who may have been in contact with cases and have since returned to the UK or are in UK overseas territories.”