Musannaf Ibn Abi Shayba 28:319

Waki' narrated to us, he said: Sufyan narrated to us, from Jabir, from Abu Ja'far, that the Prophet (peace and blessings of Allah be upon him) passed by a *naghash* (a person suffering from a disease or a leper), so he prostrated and said: "Ask Allah for well-being."