[Name] Monkeynucleosis [Source] Hey Arnold! [Symptoms] 
A disease that is caused if a person is touched by a monkey. Helga thinks she had this disease when a monkey trainer's monkey kissed her on the arm. It seems that the disease leads to death (Or, as said, "expiration") There are four symptoms: 1) puffy rash where infected, 2) sweaty palms, 3) loss of appetite, and 4) irritability. On the show, monkeynucleosis is said to have been long debunked by modern science.