Strategy and pic by Patti Frazier-Laundree
You have three infection bubbles at ceiling. One on each end and one in the center which are underlined in the strategy picture. You will be approaching this field of bubbles from three directions to stop the spread of the infection as soon as possible. Once this is done clear out the extra bubbles to get a clear shot at the ceiling. It is easy to run out of bubbles and the 7 extra bubble potion is highly recommended. I had one bubble left when I finished this game with the extra bubbles.
Here is an awesome video walkthrough for 3 Stars by Sebastian Ramirez.