Say a family in Italy were visiting the wrong part of China at the wrong time. Went home asymptomatic or what they thought was the sniffles. Four could infect a dozen or more and off you go!
Say a family in Italy were visiting the wrong part of China at the wrong time
````
say a family in Italy were in an airport and passed by a Chinese who sneezed ... no need to go to extremes - airports will suffice as a place of contagion. the infected person can show no sign 2 weeks before infection diagnosable and 2 weeks after remission before lapsing into a organ failure