From Sahih Muslim (Hadith 3342):
A'isha (Allah be pleased with her) reported:When we came to Medina, and it was an unhealthy, uncogenial place, Abu Bakr fell sick and Bilal also fell sick; and when Allah's Messenger (ﷺ) saw the illness of his Companions he said: O Allah, make Medina as congenial to us as you made Mecca congenial or more than that; make it conducive to health, and bleesus in its sa' and in its mudd, and transfer its fever to al-juhfa
Reference: Muslim 3342