i agree with the beaver. i have been trapping for almost 2 decades now and have NOT caught one yet that has not had a ton of fleas. just bag and raid them and thats all it takes. wont damage the fur-smell kinda funny but yotes stink to start with.
just an FYI-if ya have the space hang you critter (what ever they may be) upside down by their back legs. Leaving them on the concrete floor lets blood pool to the lower sections (typically stomach and groin area) an the hide turns green. Green=rot, if slightly green no worries, dark green means ya will have some fur slip when ya tan. JMHO but i have been doing this for many years, and learned from my father who was a fur farmer for many decades before.