The broad or fish tapeworm. The adult lives in the intestine of fish-eating mammals, including humans. The largest tapeworm infesting humans, it may reach a length of 50 to 60 ft or 15.2 to 18.3 m (average 20 ft or 6.1 m). The eggs develop into ciliated larvae that are eaten by small crustaceans called copepods. The larvae pass through several stages in the copepods and develop further after the copepods are eaten by fish, finally encysting in fish muscle. People acquire the infection by eating raw or poorly cooked fish that contains cysts. Infection can be prevented by thoroughly cooking all freshwater fish or by keeping the fish frozen at -10°C (14°F) for 48 hr before eating.
A type of tapeworm that is among the largest, capable of reaching lengths between 20 and 30 feet.