Musnad Abu Ya'la al-Mawsili 110:6

Narrated to us Muhammad ibn Abi Bakr, narrated to us Abu 'Awanah, from Simak, from 'Ikrimah, from Ibn 'Abbas, from the Prophet (peace be upon him), who said: "There is no contagion, no superstition, no owl (omen), and no Safar." A man said to him, "We take a mangy sheep and put it among the sheep, and they become mangy." He said, "Then who infected the first one?"