The Black Sea and Aegean Sea (Hopefully this is correct!)
One very famous, perhaps the most famous way was through improvised vaccination. Specifically, George Washington ordered his healthy men to be injected with substance taken from the wounds of the sick men during a smallpox infection.
A risk was that those men would get sick just like the the sick men did, but the the potential reward would be that they would get sick in a controlled way and that they would be able to fight this disease.
