Sahih Muslim Book 26, Hadith Number 5498.

Chapter : Plague, ill omen and magic.

Usama b. Zaid reported Allah’s Messenger (may peace be upon him) having said this: This calamity or illness was a punishment with which were punished some of the nations before you. Then it was left upon the earth. It goes away once and comes back again. He who heard of its presence in a land should not go towards it, and he who happened to be in a land where it had broken out should not fly from it.