Three passengers have died aboard a cruise ship sailing in the Atlantic, with at least one case confirmed to be linked to hantavirus, a rare but severe disease primarily transmitted by rodents.

In a statement on Sunday, the World Health Organization (WHO) confirmed an outbreak of hantavirus on board, reporting one confirmed case and five additional suspected infections. One patient remains in intensive care in South Africa, as investigations and emergency response efforts continue.

"Detailed investigations are ongoing, including further laboratory testing and epidemiological investigations. Medical care and support are being provided to passengers and crew. Sequencing of the virus is also ongoing," the WHO said in the statement.

According to the WHO and US Centers for Disease Control and Prevention (CDC), hantavirus infections are primarily linked to contact with infected rodents' urine, droppings, or saliva. Although human-to-human transmission is rare, it remains possible and can lead to severe respiratory illness, requiring close monitoring and medical intervention.

WHO added that it was "facilitating coordination" between member countries to evacuate two passengers showing symptoms of the infection, while conducting a comprehensive public health risk assessment and providing response support for those remaining on board.

Earlier the same day, South Africa's National Department of Health reported an outbreak of a "severe acute respiratory illness" on the MV Hondius, a cruise ship in the Atlantic, which had claimed at least two lives, according to AFP.