We most certainly did. I have just been reading historical accounts of those incidents. Just because people in those times didn't know the details of how diseases occur, they could certainly observe the spread of infections. Even during the Black Death bodies, clothing, and even buildings were burned to stop the disease from spreading. Cows infected with anthrax were catapulted over castle walls during the Middle Ages simply because it was well known that the infection would spread to people. Use of quarantine dates back a long long time. People knew well the scenarios related to the spread of disease, even if they didn't know the mechanism.
There is correspondence between army officers regarding taking linens from smallpox wards in hospitals for use with the Indians.