Pets as a source of pinworms in people (especially children) has been a widespread misconception. A recent article at www.medicalnewstoday.com gives a good overview of pinworms in people and has a nice section about pets.

"Pinworms that affect humans cannot infect animals or pets. However, some microscopic eggs may land on a pet’s fur

Pinworms are small white worms that live in the rectum (the very last section of the large intestine). The human pinworm is called Enterobius vermicularis. Pinworm infections tend to be fairly mild (the sight of them is often more distressing than what they actually do), causing itching around the anus. Pinworms are common in