A fertilized female whipworm periodically lays up to 3,500 immature eggs a day. Eggs come out with feces, stick to various objects. They can be found on the wall of the toilet bowl, on the fingers of unclean people and from them on money, on door handles, on the handrails of transport, on the ground, in dust, on the paws and hair of dogs, cats etc. Flies and other insects can carry eggs. Whipworm eggs ripen in the external environment for about a month and only then become infectious.