Sahih Bukhari

Narrated Abu Huraira:Allah's Messenger (ﷺ) said, 'There is no 'Adwa (no disease is conveyed from the sick to the healthy without Allah's permission), nor Safar, nor Hama."" A bedouin stood up and said, ""Then what about my camels? They are like deer on the sand, but when a mangy camel comes and mixes with them, they all get infected with mangy."" The Prophet (ﷺ) said, ""Then who conveyed the (mange) disease to the first one?