I guess somehow we are contagious, coz I noticed my office mate , and my workmate before in foodchain produces also that kind of parasites we exhale enter into my nosetril and turns me snizzing,
however, My wife for 10 years now, I can't see any symptoms that she have a similar symptoms, it seems that she is immune from sneezing, cough, although, before she experience itchyness and sneezing before ..