It seems simple enough to tell one employee to give them paid time off with a doctor referral if sick with an infectious disease.
It would avoid infecting the entire company and avoid losing profits and productivity at the same time.
If the employer either refuses or denies an employee to take time off work to recover, it would seem that the company could be held liable for damages if it resulted in the sickness of other coworkers.
I currently have evidence that one employee admitted to feeling sick and my manager has also verbally admitted to being sick.