عَنْ عِكْرِمَةَ عَنِ ابْنِ عَبَّاسٍ رَضِيَ اللَّهُ عَنْهُمَا أَنَّ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ قَالَ لَا عَدْوَى وَلَا طِيَرَةَ وَلَا صَفَرَ وَلَا هَامَةَ فَذَكَرَ سِمَاكٌ أَنَّ الصَّفَرَ دَابَّةٌ تَكُونُ فِي بَطْنِ الْإِنْسَانِ فَقَالَ رَجُلٌ يَا رَسُولَ اللَّهِ تَكُونُ فِي الْإِبِلِ الْجَرِبَةُ فِي الْمِائَةِ فَتُجْرِبُهَا فَقَالَ النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ فَمَنْ أَعْدَى الْأَوَّلَ
Syedna Ibn Abbas (may Allah be pleased with them) narrates that the Noble Prophet (peace and blessings be upon him) said: There is no contagious disease, no bad omen, no (evil in) Safar, and no reality in the owl. Simak narrates that by Safar is meant a worm that is produced in the human stomach. A man said: O Messenger of Allah! Among a hundred camels, if one camel gets mange, then because of it all become mangy. The Noble Prophet (peace and blessings be upon him) said: Well, tell me first, who caused the first one to become sick?