The increase is notable in western countries where eating sushi and other raw or uncooked fish is now more popular.
A BMJ case report highlights a case study where a previously healthy man in his 30’s 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.