Tapeworm (cestode) is a long, flat, parasitic worm that infects the human intestine, most commonly through ingestion of undercooked or raw meat/fish containing larval cysts (e.g., Taenia saginata from beef, Taenia solium from pork, or Diphyllobothrium latum from fish). The adult worm attaches to the intestinal wall via a head (scolex) with suckers or hooks and grows by adding segments (proglottids), sometimes reaching several meters in length. Many infections are asymptomatic or cause mild abdominal discomfort, nausea, diarrhea, weight loss, or increased appetite; segments or eggs may be visible in stool. In pork tapeworm (T. solium) cases, if eggs are ingested (via fecal-oral route, often from poor hygiene), larvae can migrate to tissues causing cysticercosis—most seriously neurocysticercosis when cysts form in the brain, leading to seizures, headaches, or neurological deficits.