[Hootowl99]

I have worked one Legionella out break that appeared to be ingested, not inhallation, as it was traced to drinking water fountains. For the inhalation vs. ingestion mechanism, I think it can go either way. Inhalation certainly seems the most common route though.

[Silentgypsy]

traced to drinking water fountains.

Could it have been aerosolized by the upward water stream?