TT #174 · Parshas Shemini · Aliyah 5 · Passuk 31
Chabad.org — Vayikra Chapter 11 with Rashi
English: These are the impure among the swarming things; whoever touches them when dead shall be impure until evening.
Sifra (Toras Kohanim), Shemini, Chapter 7.
Wikisource — Sifra, Shemini, Chapter 7
Textual distinction — The verse's paired expressions distinguish creatures that have died, including slaughtered creatures, from those that are alive.
The wording includes the listed creatures even when slaughtered, while excluding creatures while still alive from this impurity.