Anyone out there have any idea if fresh raw fish can cause intense intestinal spasms or cramps?

Anisakis infestation. Anisakiasis is the principal "worm" infestation of the stomach, caused by ingesting anisakis larvae in raw or undercooked fish. Within a few hours, there is severe upper abdominal pain, nausea, vomiting (relieved after endoscopic removal of worm). As you know, raw fish (sushi, sashimi) are increasingly popular--choose carefully your source of fish (farm raised, not wild caught) & food preparer.