Cruise ships are sometimes called floating cities. Icon of the Seas , with a maximum capacity of ten thousand people (passengers and crew), could accommodate most of the population of the city of Wells in Somerset. Most cruise ships are more like small if extraordinarily wealthy towns. And the MV Hondius , with 175 people from more than twenty countries on board when it departed from Ushuaia in Tierra del Fuego on 1 April, was probably the most diverse village in the world. Since the first reports of the hantavirus outbreak on the ship in early May, the travel itineraries of those villagers have been heavily scrutinised. The route of the Hondius has presented a cat’s cradle of contact tracing that emphasises just how connected these global travellers are. When the first passenger died onboard in the South Atlantic on 12 April, the nearest port was Tristan da Cunha, two and a half days away, with a population only slightly larger than that of the Hondius .…