Eucestoda the "broad tapeworm" or "fish tapeworm") and related species. Humans become infected by eating raw, undercooked, or marinated fish acting as a second intermediate or paratenic host harboring metacestodes or plerocercoid larvae. Clinical symptoms are due to the large size of the tapeworm, which often reaches a length exceeding 15 m. The most common symptom is pernicious anemia, caused by the absorption of vitamin B12 by the worm. Other symptoms include various intestinal issues, slight leukocytosis, and eosinophilia. This condition is caused by the plerocercoid larvae of the tapeworm "Spirometra". Humans become infected by drinking contaminated water, eating raw or
Alaria (trematode) haemorrhage which can lead to clinical disease. Paratenic hosts also become infected when eating the contaminated intermediate host, either tadpoles or frogs. The mesocercariae remain in organs such as the muscles, connective tissue or lungs, and eyes. They are mostly harmless in dogs as well as the paratenic hosts. However, prevalence of "Alaria" in dogs in the United States and foxes in Germany are up to 30%. Unfortunately for humans, it can be quite harmful and even cause death. Humans can be infected by ingesting "Alaria" larvae, which can be from eating undercooked frog legs or contaminated boar or pig