Back in 1918 the mode of transportation was the train...or horse...maybe a car....now its planes...and to spread an infectious disease is very easy when it can be spread in less than 24 hours worldwide....the question is not if...its when
My wife's grandad use to tell us the story many times how his family took the wagon and went to town for supplies only once a month, but during the 1917-18 Spanish flu outbreak, it took his dad going to the trainstation only one time to get some cattle, and he returned home and a week later came down with it and died. Her grandad was around 10 years old at the time and he came down with it too and was in bed for months and had to learn to walk again when he finally got his strength.