Many puppies have roundworms at birth or shortly after, due to the fact that infective roundworm larva in the female can be transmitted to the pups via the placenta before birth, or through the milk during nursing. Roundworms represent a significant public health concern, especially for children. Routine dewormings and timely removal of puppies' fecal material are the key to preventing roundworm associated problems. There are several species. Hookworms are small intestine parasites that bite the intestinal lining and feed aggressively on blood.
Heavy infestations can cause life threatening blood loss anemias, especially in young animals.
The life cycle is direct, infection can be through ingestion of eggs or penetration of the host animal's skin by infective hookworm larvae. Larvae can also penetrate human skin, causing a skin eruption termed cutaneous larval migrans. Hookworms are commonly seen in puppies, and are more frequently encountered in adults than are roundworms. There is one species. Whipworms are small, thread-like parasites of the large intestine.