Sayyiduna Farwah bin Musayk (may Allah be pleased with him) says: I asked: "O Messenger of Allah! There is a land near us called the land of Abyan; it is the land of our crops and our provisions, and it is struck by epidemic (or he said: its epidemic is severe)." The Prophet (peace and blessings be upon him) said: "Leave it, for nearness to disease brings destruction."
Al-Qutaybi said: Al-qaraf means being near to epidemic and disease.
Abu Sulayman (al-Khattabi) said: This belongs to the field of medicine, because according to physicians corrupted air is among the most harmful of things and the quickest to bring illness to the body.
The Shaykh (may Allah Almighty have mercy on him) said: This is similar to his (peace and blessings be upon him) saying: "When you hear of it (an epidemic) in a land, do not go to it." All of that happens by the will and permission of Allah, and there is no might and no power except with Allah.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الضحايا / 19582