Three dead from Hantavirus on cruise ship, WHO confirms: Symptoms, causes and what you need to know

At least three passengers aboard the MV Hondius, an international cruise ship sailing from South America toward the Canary Islands, have died following suspected infections of hantavirus, a rare family of rodent-borne viruses that rarely appears in maritime settings. The World Health Organisation (WHO) confirmed the deaths on Sunday, noting that one case had been verified through laboratory testing, with five additional suspected cases under investigation.

South Africa's National Department of Health confirmed that passengers were receiving care in South African medical facilities "following serious health complications arising from undiagnosed severe acute respiratory infection," according to department spokesman Foster Mohale. One of the survivors remained in intensive care in the country as of Sunday.

The infection progresses in two stages. Initially, it resembles influenza, producing fever, chills, body aches and headaches. As the disease advances, respiratory symptoms emerge, and in severe cases, patients develop shortness of breath followed by lung or heart failure. There is currently no approved vaccine for hantavirus and no specific antiviral cure; treatment is largely supportive.

The virus entered wider public consciousness last year when Betsy Arakawa, wife of actor Gene Hackman, died from its effects.

Among the first to fall ill was a 70-year-old male passenger who developed fever, headache, abdominal pain and diarrhoea. He died upon arrival at St Helena Island; his remains were awaiting repatriation to the Netherlands at the time of reporting. His 69-year-old wife also became ill aboard the vessel and subsequently collapsed at OR Tambo International Airport in South Africa whilst attempting to fly home to the Netherlands. She was taken to a nearby health facility, where she died.

A third patient, a British national, became ill during the leg of the voyage between St Helena and Ascension Island. He was transferred from a hospital in Ascension to a private health facility in Sandton, South Africa, where laboratory results confirmed a positive diagnosis of hantavirus.

South African authorities are conducting contact tracing in coordination with the National Institute for Communicable Diseases and Gauteng Health authorities. "There is no need for the public to panic because only two patients from the cruise ship have been within our borders," Mohale said, adding that the "World Health Organization is coordinating a multicountry response with all affected islands and countries to contain further spread of the disease."

Given that the MV Hondius had recently been in South American waters, experts say that possibility cannot be ruled out.

Emily Abdoler, a doctor and assistant professor of medicine at the University of Michigan Medical School, said the case raised serious and unfamiliar questions. "I don't know of any other cases reported on a cruise ship before," she said. Noting that the ship had recently been in South America, she acknowledged that human-to-human spread was a possibility. "This is not a common infection, but it's even less common to have the human spread raised as a possibility," she added. "Six people sick on a cruise ship -- I've never heard of that from this kind of infection."

Possible origins of the virus include rodent droppings on the ship itself or at one of the ports where it docked. Investigators have not yet formally identified the source of the infection.

Anyone who believes they may have been exposed to rodent droppings or urine, particularly in enclosed or rural environments, and who subsequently develops these symptoms, should seek medical attention immediately and inform their doctor of the potential exposure.

The WHO said it was coordinating a multicountry response to the situation aboard the MV Hondius and that investigations into the source and scale of the outbreak were ongoing.