The Hebrew that is translated as “stricken” or similar in many English translations was translated by the Latin Vulgate translation as quasi leprosum or “like a leper.” Most, if not all, Catholic translations into the 1950s used the Vulgate as their source text and therefore followed this translation — see the English Catholic Douay-Rheims version: we have thought him as it were a leper.

The translation was likely chosen because in other cases when the same Hebrew word is used, leprosy was implied.

In the middle ages this was interpreted as meaning that Jesus in fact had leprosy and that having leprosy was not a curse but a “Holy Disease.” (Source: Yancey 1995, p. 172f.)

See also leprosy / leprous