Mononucleosis (“mono”)  is an infection spread by the Epstein-Barr virus (most commonly, called EBV) or Cytomegalovirus (less commonly, called CMV). Symptoms vary significantly from person to person.  Many (possibly most) people with mono have no symptoms at all. Others may have mild fatigue or upper respiratory infection symptoms. When more severe, symptoms include extreme fatigue, swollen lymph glands, and very enlarged tonsils (often with a lot of pus or exudate on them) that can last for weeks or longer.  Mono is transmitted by contact from saliva (i.e. the “kissing disease”), coughing, sneezing, sharing food or drinks, etc. Most all humans contract EBV mono at some point in their lives, usually by the age of 30 in developing countries, though many people do not realize that they every had it (hence we rarely see mono diagnosed in adults).