Causes of tapeworm infection. In human beings, tapeworm infection is most commonly caused by the pork tapeworm (Taenia solium), beef tapeworm (Taenia saginata), dwarf tapeworm (Hymenolepis nana), and fish tapeworm (Diphyllobothrium latum) from raw freshwater fish.Most people become infected after ingesting tapeworm eggs or larvae.ish tapeworm infection is more common in countries where the consumption of raw fish is common practice, such as Eastern Europe, Scandinavia and Japan. Undercooked or raw freshwater fish, such as salmon, are the most common sources.