sorry for the late reply but both bob church ( An americian ferret expert) and Erica (vet who specialises in small animals) came over to my house about 5 yr ago on a world wide tour collecting data for ferrets taken tool samples as well as measuring each ferret, they said that over the years they have heard of worms but all ferrets with this were reared reared in Marshall farms in the united states and that they had no evidence of it, and that no ferret they had checked in in uk/europe had ever shown any signs of worms, they also reported that about about this time when they were here there