In facilitated diffusion, molecules diffuse across the plasma membrane with assistance from membrane proteins, such as channels and carriers. A concentration gradient exists for these molecules, so they have the potential to diffuse into (or out of) the cell by moving down it.
It's a new disease so no one can be sure of how fast it spreads, how it spreads, its symptoms, or anything else about it. It's an outbreak because nothing or not much is known about it.
