I think the problem is that there is no one "Entity" making the rules, so no verified list of facts.
You have general actions...TSA asking about travel in China or Iran (This week they were not asking about Italy, Japan or other countries), which I suppose would prompt health screening, but not necessary quarantine. You also have specific steps...a Cruise ship with active cases being quarantined, or people evacuated from China. And finally, places like your School, or my Company who have requested self Quarantine if traveling to specific areas.
Of course all that changes every day. While I was traveling the last two weeks, my company added Japan, South Korea, and Italy. Hot spots popped up in Spain (a hotel quarantined), another cruise ship, and Italy widened it's controls.
For the most part, other than a broad declaration, others will decide if your connection is "close enough" at the extreme end, but at some point, given that you work with a potentially vulnerable population, you will need to determine if your travel presents a risk, and that could change daily.