The outbreak of hantavirus, an infection that is usually transmitted to humans from rodents, occurred on a cruise ship that was traveling from Argentina to Cape Verde. Though rare, hantavirus may spread between people and belongs to a family of viruses that can cause hemorrhagic fever and acute respiratory illness.

The World Health Organization said one case of hantavirus infection has been confirmed, with five more suspected cases under investigation.

The World Health Organization said Sunday that three people have died aboard a cruise ship in the Atlantic Ocean, one a confirmed case of hantavirus, an...