A deadly virus normally found on land has somehow invaded a cruise ship. An outbreak of the hantavirus has likely sickened half a dozen people and killed several aboard the MV Hondius , a 170-passenger vessel traveling between Argentina and Cape Verde, an island nation off the western coast of Africa. World Health Organization officials confirmed the outbreak over the weekend. So far, one case of hantavirus infection has been confirmed, along with five other suspected cases, while three people have died following their illnesses. Though officials are still working to identity the exact origin of the outbreak, hantavirus normally isn’t a contagious disease that spreads easily between people. Deadly but rare Hantavirus describes a large family of viruses, only some of which are known to sicken people. These viruses are further divided into two broad groups: those found in the western hemisphere (or “New World”) and those in the eastern hemisphere (“Old World”).…