Sayyiduna Abu Hurayrah (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings be upon him) said: "Do not hold back milk in the udders of camels and goats. Whoever buys (such an animal) after that has two options after milking it: if he wishes he may keep the animal, or he may return it; if he returns it, he should give a sa' of dates along with it."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب البيوع / 10736
Amr bin Dinar (may Allah have mercy on him) said that Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) bought camels suffering from the thirst disease from the partner of Nawwas.
(b) Amr bin Dinar (may Allah have mercy on him) said that Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) bought camels suffering from the thirst disease from the partner of Nawwas. He told Nawwas: I have sold them to such-and-such an old man. Nawwas said: Woe to you! That was Sayyiduna Abdullah bin Umar (may Allah be pleased with them both). So Nawwas came to Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) and said: My partner sold you camels suffering from the thirst disease and did not inform you of it. He said: Then drive them away. When he went to drive them off, Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) said: Leave them! We are content with the judgement of the Messenger of Allah (peace and blessings be upon him) that "disease is not contagious."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب البيوع / 10737