South African health authorities are treating cruise passengers after a suspected hantavirus outbreak linked to a vessel sailing the Atlantic Ocean.

Three passengers aboard MV Hondius have died from suspected infections, while additional cases are under investigation, according to the World Health Organization (WHO).

South African authorities confirmed that at least two individuals linked to the voyage had entered the country for treatment following what was described as a severe acute respiratory illness.

One patient remains in intensive care in Johannesburg, while another who was evacuated to the country died shortly after arrival. Two others required urgent medical attention after the vessel reached waters off Cape Verde.

The expeditionary cruise ship, carrying around 150 passengers, departed Ushuaia in Argentina roughly three weeks prior and followed an itinerary through Antarctica, the Falkland Islands, South Georgia, and several South Atlantic islands before heading north towards Cape Verde.

Health officials in South Africa are now working alongside the National Institute for Communicable Diseases and regional authorities to trace contacts and assess potential exposure risks.

The WHO has initiated a multi-country response, coordinating with jurisdictions across the ship’s itinerary.

One case of hantavirus has been laboratory confirmed, while five additional infections remain suspected. Of the six individuals believed to be affected, three have died.

Among the confirmed cases, a British passenger tested positive for hantavirus after being transferred to a private medical facility in South Africa. Another passenger, a Dutch national, died after arriving in St Helena, while his wife later collapsed at O.R. Tambo International Airport and died in hospital.

Authorities have emphasised that the risk to the wider public remains limited.

“There is no need for the public to panic because only two patients from the cruise ship have been within our borders,” said Foster Mohale, spokesperson for South Africa’s National Department of Health.

The source of the infections remains under investigation. Hantavirus is typically transmitted through contact with rodent droppings or urine, often via inhalation of contaminated particles. It is not commonly associated with cruise ships, where outbreaks are more frequently linked to highly communicable illnesses such as norovirus.

Oceanwide Expeditions, the operator of the vessel, confirmed that it is monitoring the situation and coordinating with health authorities.

While most strains of hantavirus are not transmitted between humans, the Andes variant, found in parts of South America, has shown limited potential for person-to-person spread, raising additional questions given the ship’s itinerary.

The vessel remains off the coast of Cape Verde, with decisions pending on whether further medical evacuations will be required.