Volume 7 · Book 71 · Hadith 665e
Narrated Abu Huraira: Allah's Apostle said: The cattle (sheep, cows, camels, etc.) suffering from a disease should not be mixed up with healthy cattle, (or said: "Do not put a patient with a healthy person ). " (as a precaution).
— Sahih Bukhari, Volume 7, Book 71: Medicine, Hadith #665e