Exodus 8:16-17

16Then the Lord said to Moses, “Say to Aaron, ‘Extend your staff and strike the dust of the earth, so that it may turn into 1gnats through all the land of Egypt.’”

17They did so; and Aaron extended his hand with his staff and struck the dust of the earth, and there were 2gnats on every 3person and animal. All the dust of the earth turned into 45gnats through all the land of Egypt.