Seriously?
Child Care centres are germ factories as the best of times. If we got worried overtime something went though the place we'd never send our kids there.
In the past few month's my son's centre has had hand,foot and mouth, a few rounds of gastro and head lice (and these are just the ones I know about). Then there is the running into shit and knocking themselves out, other kids biting them etc.
Just last week in the toilets at the airport, I had to keep telling my 2yo to stop playing with the urinal whilst i was trying to take a piss.