WHO says cruise ship hantavirus cases likely began with infection off board, risk low

The World Health Organization (WHO) said Tuesday that a hantavirus outbreak on a cruise ship off the coast of Cabo Verde likely began with the first case being infected before boarding and assessed the overall risk to the public as low.

Maria Van Kerkhove, the agency’s director for epidemic and pandemic preparedness and prevention, told reporters in Geneva that the initial patient and his wife were likely infected outside the vessel.

“Our assumption is that they were infected off the ship,” she said, citing the virus’s incubation period.

She added that limited human-to-human transmission among close contacts is being investigated, which can occur over a period of one to six weeks.

Seven of the 147 passengers and crew have been reported ill, including two confirmed and five suspected cases.

"Sadly, three have died," she said.

One patient is in intensive care in South Africa and improving, while two others remain on board and are being prepared for medical evacuation to the Netherlands.

Passengers have been asked to remain in their cabins as a precaution while disinfection and other public health measures are carried out. No additional symptomatic cases have been reported so far.

Hantaviruses are carried by rodents and can cause severe illness in humans, though human-to-human transmission is rare, she said, noting that sequencing is underway to determine the exact virus, with the Andes virus among the working assumptions.

The official added that authorities have found no evidence of rodents on board the ship, while the vessel’s multiple stops along the African coast may have exposed passengers to wildlife, which could explain additional infections.

WHO is coordinating with authorities in Cabo Verde, the Netherlands, South Africa, Spain and the UK, as well as the ship’s operators, while investigations including contact tracing and virus sequencing continue.

The ship is expected to proceed to the Canary Islands after the evacuation of a number of infected patients, where Spanish authorities will conduct a full investigation and disinfection, she said.

The Dutch ship, MV Hondius, was on a weekslong Polar cruise from Argentina to Antarctica.