© Charles Chandler
15 And the Lord will take away from you all sickness, and none of the evil diseases of Egypt, which you knew, will he inflict on you, but he will lay them on all who hate you.
22 The Lord will strike you with wasting disease and with fever, inflammation and fiery heat, and with drought and with blight and with mildew. They shall pursue you until you perish.
27 The Lord will strike you with the boils of Egypt, and with tumors and scabs and itch, of which you cannot be healed.
This implies that at least some of the diseases in Egypt had been inflicted intentionally.