Doctors warn there may be parasites lurking in your sushi

(CNN) – A condition called anisakiasis is on the rise – an illness caused by eating fish or seafood contaminated by parasites.

That increase is notable in western countries where eating sushi and other raw or uncooked fish is now more popular. The report from BMJ case reports highlights a case study: a previously healthy man in his 30’s who developed severe upper gut pain. A week later he was in the hospital, with an upper gastrointestinal endoscopy performed to reveal a parasitic worm penetrating his stomach. The man said he had recently eaten sushi.

The study’s lead author says Japan typically sees the most cases of the parasitic herring worm disease. But, new estimates suggest there are several thousand cases now in Spain and the Centers for Disease Control says cases are showing-up in the United States, South America, Europe and elsewhere. Scholars on the topic suggest the illness in general is under-estimated and under-diagnosed.