Theory Emerges on Origin of Ship's Deadly Virus

Investigators are still trying to figure out how a rare and deadly hantavirus emerged on a cruise ship, and a new theory has surfaced in Argentina. Officials there tell the AP that a Dutch couple may have contracted the virus while on a bird-watching trip in the country before boarding the MV Hondius. The couple visited a landfill on the bird-watching tour and might have been exposed to rodents or rodent droppings, the usual way in which the virus is spread. Once on the ship, the virus appears to have spread via human transmission, which is rarer.

"We do believe that there may be some human-to-human transmission that's happening among the really close contacts, the husband and wife, people who've shared cabins," Maria Van Kerkhove of the World Health Organization told reporters on Tuesday, per NPR. Three people have died, and five more are ill. (Three ill patients were evacuated on Wednesday, including the ship's doctor.) Not every case has been officially confirmed to be hantavirus. One man who left the cruise earlier is being treated in a hospital in Switzerland, where authorities are rushing to trace his contacts, reports the Wall Street Journal. The WHO says the risk to the general public remains low, however.