The World Health Organization (WHO) unusually raised the possibility of human-to-human transmission in connection with a hantavirus outbreak on a luxury cruise ship sailing the Atlantic.
Maria Van Kerkhove, WHO infectious disease response Director-General, said on the 5th (local time) that "there may have been human-to-human transmission among very close contacts." This is an unusual assessment given that hantaviruses are known to be transmitted mainly through rodents. She also raised the possibility that the index patient may already have been infected with hantavirus before boarding the cruise ship.
The vessel in question is the Netherlands-flagged cruise ship "MV Hondius," which is currently staying in waters near Cabo Verde, an island nation in West Africa. According to the WHO, a total of seven cases have been reported on the ship so far—two confirmed and five suspected—with three deaths among them.
The dead are a Dutch couple, ages 70 and 69, and one German national. In particular, the Dutch couple, the first fatalities, were confirmed to have traveled in South America before boarding, adding weight to the possibility that the source of infection was external rather than onboard.
About 150 passengers are effectively confined on board, unable to disembark. The Cabo Verde government has denied entry over public health concerns and is responding by deploying only medical personnel. The WHO initially considered moving the ship to Spain's Canary Islands, but the Spanish government and local authorities were reportedly reluctant to accept it. Canary Islands authorities effectively refused entry, saying "it would be reasonable for the ship to return to the Netherlands."
The WHO said it received reports that no rats were found on board, drawing attention to a pattern different from established transmission routes.
Hantaviruses are mainly transmitted when the excreta or saliva of rats becomes airborne. Rare cases of human-to-human transmission have also been reported. The incubation period can last for weeks, and initial symptoms resemble the flu; in severe cases, the virus can damage lung and kidney function, leading to fatal outcomes. The virus is also known to have been first discovered and named by the late Korean virologist Dr. Lee Ho-wang in the Hantan River basin.
The WHO warned against excessive fear, saying "the current risk to the general public is low."