The World Health Organization is investigating a suspected case of human-to-human transmission of hantavirus aboard a cruise ship in the Atlantic Ocean. The outbreak, which has infected 7 people and killed 3, involves the MV Hondius, a polar cruise vessel travelling from Argentina to Cape Verde.

WHO official Dr. Maria Van Kerkhove confirmed that while the rodent-borne illness is not easily spread, the possibility of transmission among close contacts-such as couples sharing cabins-cannot be ruled out. The ship has been anchored off the coast of Cape Verde, where authorities refused to let passengers disembark due to public health concerns.

Three passengers have died: a Dutch couple and a German national. One patient is critically ill in South Africa, and two others are awaiting medical evacuation to the Netherlands. All remaining passengers have been confined to their cabins as the vessel undergoes decontamination.

Van Kerkhove assured those aboard that the WHO is working with the ship’s operator, Oceanwide Expeditions, as well as Spanish authorities. The ship is expected to continue to the Canary Islands, where it may be allowed to dock.