Leslie Landon, Michael Landon's daughter, is seen as a sick girl in the church in this episode. She will appear in several future episodes, as well as playing the recurring role of Miss Plum, the school teacher, in season 9. Leslie Landon also reported that it took her father, Michael Landon, a couple of takes to do the scene because he felt he was too emotional.
On the exact day this episode aired, Melissa Gilbert (Laura Ingalls) was introduced to her new little sister Sara Gilbert. Sara Gilbert played Darlene in the TV show Roseanne.
Peacock (streaming channel) has The Plague and Circus Man reversed. It lists Circus Man as #18; The Plague as #19.
Matt Clark appears in this episode as "Eric Boulton", a man whose wife and son die after contracting Typhus after eating rat-infected cornmeal. He would return in Season Five's "Mortal Mission" as a character whose family die from Anthrax infected meat.