As the tapeworm progresses through its life cycle, the female lays eggs in the flesh of the fish. These eggs cannot be seen with the naked eye. However, once the fish is eaten uncooked, the eggs hatch in the human intestine, anchor themselves to the bowel lining and mature into adults that can sometimes reach prodigious lengths of up to 30 feet. Fish tapeworm often causes anemia, weight loss, abdominal pain, and anal irritation. The diagnosis depends on a stool analysis.
Treatment is universally successful.
Bacteria readily multiply on uncooked flesh, and if the raw fish is not handled properly, refrigerated and cleaned before consumption, it can cause food poisoning that can be quite troublesome to treat, because it may be associated with severe nausea, vomiting and diarrhea, leading to dangerous dehydration. Again, let me emphasize that, by and large, sushi is safe to eat and causes no health problems.