Probably most ferrets have ear mites (Otodectes cynotes) at some time in their lives. They can be acquired from, or transmitted to, dogs, cats, and other ferrets. If you own both a cat and ferret, and one of them has ear mites, the other probably does too, unless there is no contact at all between the two animals. Ear mites do not live long off the host, and are unlikely to be carried from place to place by a human being, the way fleas often are. However, cats and ferrets that sleep in the same areas, even at different times of the day, can transmit ear mites to each other. It takes about 3 weeks for the parasite to go through its whole life cycle, from egg to mature mite.

Mite eggs are resistant to treatment. Treatments should be carried out keeping this in mind. One treatment kills only the mature mites. After a few days, a new generation will have hatched from eggs in and around the ear. Medication used in the ear is effective for only a few days, and a single treatment will rarely kill 100% of the mature mites. It therefore takes at least 2 treatments, and usually more, spaced at 1-3 week intervals, to truly eliminate ear mites. Shortening the treatment intervals will kill the adults faster and reduce the symptoms of infestation. It will make no difference to the length of time treatment is needed, because this depends on the rate at which mite eggs hatch.

Any ear mite medication safe to use in cats is safe for ferrets. If the ears are inflamed, it is best to use a medication to control infection and inflammation before using any anti-mite treatment. A veterinarian can prescribe a suitable otic ointment. When infection is controlled, use the anti-mite treatment as directed by your veterinarian. Depending on the type of medication, this is often once a week for a few weeks, then about once a month to completely control mites. Spray the ferret with a flea killer to destroy any mites on the coat. The tip of the tail is a spot where mites may be hiding, because the ferret sleeps with his tail tip near his ears. When persistent treatment eventually rids a spayed or neutered pet of ear mites, the ears will rarely need cleaning.