Sometimes the Ivomec shots are not enough, especially if your fuzzies are scratching other areas of teir bodies. We run a shelter and recently got 3 ferrets in with the worst mite problems we have ever seen. We have been giving Ivomec shots every 7-10 days. Check with your vet. sometimes these little bugs can be persistent. Feel free e-mail us at [log in to unmask] Furry O's ferrets [Posted in FML issue 2550]