Herring Worm Disease
Have abdominal pain? It might be a herring worm infestation. When an infected sea mammal poops, the cleanup crew (shrimp, crabs, etc.) eat the poop. Then your future sushi eats that animal. You then get the herring worms when you eat uncooked fish.
Got a tingly feeling in your mouth right after you eat sushi? Might be a herring worm. Vomiting? Your body is trying to get rid of it. Stomach pain? Your new roommate has set up home in your guts.