Mishkat al-Masabih 23 Medicine and Spells كتاب الطب والرقى 62

وَعَنْهُ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «لَا عَدْوَى وَلَا هَامَةَ وَلَا صفر» . فَقَالَ أَعْرَابِي: يَا رَسُول فَمَا بَالُ الْإِبِلِ تَكُونُ فِي الرَّمْلِ لَكَأَنَّهَا الظباء فيخالها الْبَعِير الأجرب فيجر بِهَا؟ فَقَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «فَمن أعدى الأول» . رَوَاهُ البُخَارِيّ

He reported God’s messenger as saying, “There is no infection, no hama , and no serpent in a hungry belly.” A nomadic Arab asked, “Messenger of God, how is it that when camels are in the sand as if they were gazelles* and a mangy camel comes among them it gives them mange?” God’s messenger replied, “Who infected the first one?” Bukhari transmitted it. * The comparison is used to indicate the clearness of their skin.