I asked this question a while back on a quaker forum, as long as you don't put your mouth near his ( like my boyfriend plays a game with our quaker, Pretending he's gonna eat him and he'll open his mouth and act like he's eating the quakers head) he'll be fine i was told as long as none of the sick persons salvia (or for that matter salivia at any time sick or not) doesn't get near the bird's beak he can't catch nothing
when my b/f plays this game with out quaker its at the back of his head and only a feather or 2 touches his lip - but then Billy will turn around and open his beak real wide like my b/f just did with his mouth and then go off into his laughing fit
Our quaker actually coughs every single time some one coughs, and he didn't do it often until my b/f and kids were sick a while back, now he does it just about every single time some one coughs - - It is cute though