A tapeworm infection starts after ingestion of tapeworm eggs or larvae.
An adult tapeworm consists of a head, neck and chain of segments called proglottids. When you have an intestinal tapeworm infection, the tapeworm head adheres to the intestine wall, and the proglottids grow and produce eggs. Adult tapeworms can live for up to 20 years in a host. Intestinal tapeworm infections are usually mild, but invasive tapeworm infections can cause serious complications.