Don,

It was always my understanding the fungus that causes thrush is present in all of our oral cavities. It is part of a balanced mini oral ecosystem where many different bacteria play different roles. We are part of a group where that balance is out of whack. The thrush fungus that almost everybody has in moderation ends up growing out of control. So you don't have to worry about spreading it to others.

I know that when my doctor prescribes an antibiotic for me he also puts me on the anti-thrush tablets. He said that killing off a bacterial infection elsewhere in my body could also result in killing off some of the good bacteria in my mouth that keeps the thrush fungus in check.

I may be completely wrong on this so if someone knows better, please chime in.