This dude must have known everyone. Seven degrees of separation or closer
One sneeze on an airplane in close quarters...how many pieces of wet fluid is released and hits people in the vicinity, and then they arrive home in their city, get infected, and then sneeze on how many people... and they go home...etc. Body fluids can be released in contact many ways. Wipe their nose and use the doorknob to a public restroom, I mean how long does it take to dry and not be transmitted by another passing into the room?
Seven degrees of seperation or closer....how much distance does a sneeze cover?