“It is diseases thought to be multi-determined (that is, mysterious) that have the widest possibilities as metaphors for what is felt to be socially or morally wrong.”
In 1977, two years after being diagnosed with breast cancer, Susan Sontag published Illness as Metaphor—not a personal account of her experience, but rather an examination of the ways our culture layers meaning onto illness in the metaphors we use to discuss it. The less the causes of illness are understood, the more likely it is to be seen in aesthetic terms (as TB was in the 19th century) or as a product of our grief, anxiety, or repression.
In the ancient world, diseases, particularly infectious ones, were always a sign of social wrongs—an answer to immoral behavior. The plague upon the city in Oedipus Rex, for example. Plagues were viewed as a divine punishment and purifier.
We can see examples in the Torah of this same thinking, even regarding individual afflictions. We like to cite “El na refa na la” as a prayer for healing (it has such lyrical brevity), but we tend to forget the fact that Miriam is stricken with scaly skin as a punishment for a loose tongue. If we look truthfully at that passage, Moses can only appeal this way for the curse to be lifted because God has cast it upon her. The genesis of this prayer is the view that disease is a punishment for immoral behavior.