I have in front of me some stuff called Beaphar anti parasite spot on for ferrets , it sayes its effective on fleas, lice, mange mites, roundworm & OTHER MITES
I have never used the stuff personally & it sayes it contains ivormectin , i origonally got the stuff as it said it was effective against fleas but there seemed to be some confusion as to wether ivormec actually kills fleas so its not been used
Worth further investigation though , hope this helps