Lets say you are told to self quarantine or even if you do get sick and you find you caught it at work.
Can they force you to use your sick days or could this be a case for workers comp since you did get this thru work?
I’m sure a great many people got the flu through work and consequently took some days off. Have you ever heard of any of them getting workers comp for this?
If you got it because of a needle stick while handling medical waste, sure. Worker’s Comp.
If you caught it from a co-worker or customer - nope.
Oh, and you need to have recorded the needle stick, or other accident, at the time it happened. There are forms.
IME, “they” can force you to account for time off in any way they decide. Last May I was away from work twice for outpatient heart procedures (stents). Each time I was out for about 5 work days which did not line up precisely with the week (ie. Thurs thru Wed or suchlike). I blithely used the short term disability number to account for my time. After a few weeks, I received a nasty-gram from HR informing me it was denied since no “full” weeks were missed. And also warning me I should apply this to either PTO or vacation, or face disciplinary action for being away without leave. The message ended with a warning to take care of this issue immediately.
I have no doubt private employers will force workers to use PTO or sick and vacation time to account for any self-quarantines or illness.
FWIW: I did take care of the issue “immediately” and on that same day filled out the necessary forms. Some of you probably read my thread about it. It was titled “I have retired.” 
Democrats have introduced a bill to require sick time for corona virus. I’ve seen on the news elected officials in California requesting that companies do this, can’t find a cite. All of which implies that this isn’t required now.
The push is to try to ensure that workers without sick leave don’t come to work sick and infect their fellow employees and customers. Which is sure as hell going to happen with current policies.