March 11, 2020, Las Vegas, Nevada I bumped elbows with my colleague Cliff Dickinson and we laughed.  It was the fourth or fifth time someone had bumped elbows with me instead of shaking my hand, although many other attendees of the Las Vegas Conexpo trade show had shaken my hand.  “I really don’t give a shit,” one exhibitor said at a crane manufacturing booth in Festival Hall.  “If I’m going to get sick, it’s already happened.” Conexpo, the largest construction trade show in North America, seemed like a pretty good barometer for whether I should worry about my upcoming trip or not.  With 130 thousand attendees from all over the world, I figured if they weren’t panicking I shouldn’t either; I should go ahead and take my flight the next day to Casablanca, where I would meet two friends to travel to Bangui in the Central African Republic, followed by…