What action did Prophet Muhammad (peace be upon him) take upon arrival in Medina to protect the inhabitants from frequent diseases?
 Narrated `Aisha:                     When Allah's Apostle reached Medina, Abu Bakr and Bilal became ill. When Abu Bakr's fever got worse, he would recite (this poetic verse): "Everybody is staying alive with his People, yet Death is nearer to him than His shoe laces." And Bilal, when his fever deserted him, would recite: "Would that I could stay overnight in A valley wherein I would be Surrounded by Idhkhir and Jalil (kinds of goodsmelling grass). Would that one day I could Drink the water of the Majanna, and Would that (The two mountains) Shama and Tafil would appear to me!" The Prophet said, "O Allah! Curse Shaiba bin Rabi`a and `Utba bin Rabi`a and Umaiya bin Khalaf as they turned us out of our land to the land of epidemics." Allah's Apostle then said, "O Allah! Make us love Medina as we love Mecca or even more than that. O Allah! Give blessings in our Sa and our Mudd (measures symbolizing food) and make the climate of Medina suitable for us, and divert its fever towards Aljuhfa." Aisha added: When we reached Medina, it was the most unhealthy of Allah's lands, and the valley of Bathan (the valley of Medina) used to flow with impure colored water.