To attenuate fears a bit... Aerosol transmission was proven possible if you're sitting inside a vapor inhalation chamber equipped with a nebulizer spraying out liquid droplets containing >2% w/v brain homogenates from terminally scrapie-sick mice.

Rest assured if you somehow get infected by PrPSc through airborne transmission, someone was trying really hard to make that happen.

They used a nebulizer to spray infected brain matter into the air. There was no aerosolized mouse to mouse transfer.