One more tid bit, dogs (and people) with worms virually never get immune diseases including allergies. And those people with the worst allergies are most resistant to worms. The theory is that many immune diseases, including auto-immune diseases are caused by an immune system geared up to fight parasitic worms, but with "nothing to do". Worm-free animals (and people) are a recent phenominon in evolutionary times. Pig roundworms, that do not complete their life-cycle in humans, are actually being tested as a treatment for irritable bowl syndrome (an auto-immune disease). Don't think that I am advocating not deworming your pets. Our pets' (and people's) lives have never been so long and healthy. But getting old brings on a host of new diseases. However the alternative is not so good either.
