If sick patient 1 has it for 2 weeks before getting symptoms, everyone he meets in those weeks and most of the surfaces he has touched, or sprayed while talking have the potential of spreading it.   

( I get refrigerators pretty cheap especially ugly colors , I sand them down and go to a friends body shop and spray them white , they look like new)

I would then see if I could put a spray-insulation with soundproofing qualities in the walls between the studs (ask an experienced handyman or contractor).

It takes longer to prep since you have to cover EVERYTHING if you are spraying ceilings, then cleaning the sprayer properly when you are done takes a good chunk of time.  

Any damage done(paint spills or spray) will be deducted from the deposit.

In 6 months they broke 3 light fixtures - I had reports their kids were spraying a garden hose from the outside of the house into the kitchen, broke a large kitchen cabinet door, broke several plastic pieces of a new higher end Fridge, fist sized hole in the wall, carpet stains and the entire house may need another repaint, damaged woodwork, scratched kitchen cabinets, stole the curtain rods, curtains my wife spent a lot of time picking out stolen, destroyed the back yard - let the weeds grow several feet tall in the flower beds etc.  

My AC evaporator luckily has an access panel that is easily removed and then a service plug in the side panel of the coil (plastic disc wedged into sheet metal) that I was able to remove, liberally spray down the coil on the 'incoming air side' with cleaner bought from lowes, and carefully spray some water onto the coils from the easily accessible 'outgoing air' side to back rinse after waiting the recommended time. 

I've seen the spray-in foam insulation for walls, but I am not sure if it would work in a ceiling or if that's advisable.

I get on my back underneath the vehicles with spray paint and fluid film. 

It's like in the show "Breaking Bad" where they have a pallet of money in a storage unit and the wife goes in to spray so the bugs don't eat it all.