How did a rat-borne virus on a cruise ship become a global health scare?

How did a rat-borne virus on a cruise ship become a global health scare? While the luxury MV Hondius sailed across the Atlantic, passengers became sick with what was then a mystery virus - and eventually died. Two elderly Dutch nationals, a man and woman, were the first to pass away from the disease and it was later confirmed a German also died. We now know that the deaths were caused by the Hantavirus, a rat-borne disease which is usually spread through their urine, droppings and saliva. But the World Health Organization has now said it believes a rare-strain of the virus on board the ship has meant it can pass from person to person - prompting an international health scare.