Leviticus 11:38
If water is poured on the seed and their dead bodies fall on it, the seed is unclean for you.
Treasury of Scripture Knowledge
Summary
But if any water be put upon the seed, and any part of their carcase fall thereon, it shall be unclean unto you.
General references
Bible References
General references
Leviticus 11:24
Regarding the creatures mentioned above, this is how you would become unclean: When you touch their dead bodies you will be unclean until evening.