The "Legion Fever" referred to with such dread is legionellosis or Legionnaire's Disease. The disease, caused by inhaling a water-borne bacteria in aerosol, had been first diagnosed the previous summer at a convention of the American Legion in July of 1976. This episode was first broadcast in February of 1977. However, three weeks before the broadcast the CDC announced that it had identified the causative organism behind legionellosis.
In the scene where the two airline attendants are sent to see Dr. Quincy before leaving the hotel, they are told to go to Room 227. Quincy is actually in Room 218.
Actor/comedian/writer Milt Kamen, who plays Leo Burke in this episode, passed away 20 days after this episode first aired.