It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that he (peace and blessings be upon him) said: "Disease is not contagious." Then a Bedouin stood up and said: O Messenger of Allah (peace and blessings be upon him)! What do you say about healthy camels that are like gazelles, then a mangy camel comes among them and they all become mangy? He (peace and blessings be upon him) asked: "Then who gave the disease to the first one?"
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النكاح / 14237