Figure 30.12 Reaching a New Host by a Complex Route The broad fish tapeworm Diphyllobothrium latum must pass through the bodies of a copepod (a type of crustacean) and at least one fish before it can reinfect its primary host, a mammal. Such complex life cycles assist the parasite’s colonization of new host individuals, but they also provide opportunities for humans to break the cycle with hygienic measures (such as thoroughly cooking food to kill the parasites).