Three people have died and one is in critical condition after a hantavirus outbreak aboard a luxury cruise ship that sailed from Argentina to the Canary Islands. The virus has infected at least six passengers, according to the WHO (World Health Organization).

On Sunday, the MV Hondius cruise ship was in the port of Praia, the capital of Cape Verde. The WHO received a report that one of the patients' samples had tested positive for hantavirus, which causes haemorrhagic fever and respiratory problems. As of the latest count, of the six patients, three have died and one is in intensive care in South Africa.

The source of the infection is still unknown. The virus typically affects animals and is transmitted to humans through direct contact with the excrement (saliva, faeces, urine) of carriers, mostly rodents. The first victims were a couple, a 70-year-old man and a 69-year-old woman. The man died on board and his body was taken to the island of Saint Helena, a British territory. The woman died in South Africa, where she had received treatment.

The WHO has reported that it is carrying out "detailed" investigations and that "passengers and crew are receiving medical attention". Two passengers with symptoms remained on board. The countries and health authorities involved coordinated their evacuation.

If the authorities coordinate the correct isolation and evacuation of the other two infected individuals and five others suspected of having the disease, the cruise ship could continue to its destination in the Canary Islands.

The remaining passengers and the 70 crew members remain on the ship, which has a capacity of 170 passengers. Specialist personnel is evaluating their state and the situation aboard.

The most dangerous cases of hantavirus for human life are usually those that cause respiratory complications, which appears to be the case for those who died on the cruise ship and the patient admitted to the ICU.

"Although rare, hantavirus can be transmitted between people and can cause serious respiratory conditions that require monitoring, support and response to the patient," the WHO states.

The health association is already working to coordinate with the affected member countries and the ship's authorities for the evacuation of the two passengers who have shown symptoms. It is also conducting a health risk assessment and providing support to the remaining passengers.

"We have informed our national focal points in accordance with international health regulations and will issue an outbreak notice," the WHO statement concludes.