The Prophet (ﷺ) said, 'No 'Adwa (i.e. no contagious disease is conveyed to
others without Allah's permission); nor (any evil omen in the month of)
Safar; nor Hama" A bedouin said, "O Allah's Messenger (ﷺ)! What about the
camels which, when on the sand (desert) look like deers, but when a
mangy camel mixes with them they all get infected with mange?" On that
Allah s Apostle said, "Then who conveyed the (mange) disease to the
first (mangy) camel?"
Sahih al-Bukhari Book 76, Hadith 84