> Healthy ferrets were placed in a cage that was above infected ferrets (as droplets should not rise against gravity) and the cages were connected with pipes th

> Healthy ferrets were placed in a cage that was above infected ferrets (as droplets should not rise against gravity) and the cages were connected with pipes that had a series of 90 degree bends (as droplets should not make the turns). In the SARS-CoV-1 pairings, all 4 healthy ferrets subsequently tested positive. In the SARS-CoV-2 pairings, 2 of the 4 ferrets tested positive. Thus, the infection spread through the air, around corners, and against gravity, which is inconsistent with droplet transmission, but describes aerosol transmission perfectly.