Sahih Bukhari
Medicine
Volume: 007 / Book Number: 071 / Hadith Number: 608
Narrated Abu Huraira:
Allah's Apostle said, '(There is) no 'Adwa (no contagious disease is conveyed without Allah's permission). nor is there any bad omen (from birds), nor is there any Hamah, nor is there any bad omen in the month of Safar, and one should run away from the leper as one runs away from a lion ''