Snails are the vector. Females live in a groove in male worm's back. Usually only one tapeworm present. Most infections are harmless - not detected. Trichinosis - Trichinella .
Meat eating animals are susceptible.
Pigs are one of the few carnovores that humans consume. Pigs become infected by eating contaminated garbage. Neither people or animals consume human flesh - human infection is a dead end. Ascariasis - Ascaris . Large and common, common with poor sanitation - especially where human waste is used for fertilizer.