Typhus is spread to humans through infected fleas. In this episode, Doc Baker goes to the church stating that he thinks it's typhus. Later on, he tells Charles that he's been exposed and to stay away from his family. Doc Baker exposed the entire church congregation the day before. Technically, it doesn't matter since typhus isn't spread from human to human. In this episode we see that it's the rats that are the reason and the fleas that have now hitched a ride on the corn meal into the homes of the townspeople.