My father in law is a pilot (currently not showing any systems virus) has been back and forth between China, Korea, HK (Guangzou most recently) at least 3 times

My father in law is a pilot (currently not showing any systems virus) has been back and forth between China, Korea, HK (Guangzou most recently) at least 3 times since January. His last trip he was one of only 30 people in the hotel, being monitored every 30 minutes or so for fever while on a layover. His company is still scheduling him trips there, so I have no doubt with companies still requiring similar travel that it could have easily gotten back to China from someone who has been in the US over the past few months, now that we know it has been in the wild here for at LEAST 6 weeks.