If someone has been violently ill, should he or she be arrested in the interest of protecting others?

That's what hospitals are for.

Shunned, not arrested. 

If someone is ill, I don't think NOT helping them is a good idea.
It's in the air.  Yes.  It is easily passed from person to person but isn't going to stop the virus. It will still be in the air.  Period.  The only way for no one to catch the virus that I can see is for everyone stop breathing. Then no one would have it.

Punishing the unfortunate by imprisoning them who have COVID-19  is NOT going to help their mental or physical healing.  We will all still be breathing the same air. 

How about from a hangover or food poisoning?

Four his own safety from others, he should be put in infected custard'y ....even more so if he's showing signs of Yellow Fever...or try's to touch my HOT SPOTS..  :(

First, would have to be contagious and I still say no. That would turn into the biggest fiasco ever.

It is interesting that some automatically assumed you were talking about COVID.

Violently ill can mean two different thing......it means you could be violently insane or maybe close to death with a huge array of differnt hugs...

I do not believe being ill is a crime. 

No