The Messenger of Allah ﷺ said, "There is no contagion, no Safar, and no owl-omen."An Arabi asked, "Then what about camels that are out in the sand looking like gazelles, and a mangy camel mingles with them and gives them mange?"The Prophet ﷺ replied, "Then who infected the first one?"
حدثنا عبد الرزاق وعبد الأعلى عن معمر عن الزهري عن أبي سلمة
قال رسول الله ﷺ لا عدوى ولا صفر ولا هامة قال أعرابي فما بال الإبل تكون في الرمل كأنها الظباء فيخالطها البعير الأجرب فيجربها فقال النبي ﷺ فمن كان أعدى الأول
Its isnad is sahih. Bukhari narrated it, with an addition at the end, 10:205-206, through the route of Hisham bin Yusuf, from Maamar, with this isnad. Bukhari also narrated it, 10:144, and Muslim, 2:189, through the narration of Salih bin Kaysan, from Zuhri, and it is established with the two Shaykhs and others, in longer and shorter forms, through many routes from Abu Hurairah. See also what has preceded in the Musnad of Abdullah bin Amr, 7070, and what we pointed out there regarding the hadiths.