Since this nematode infects fish as its primary host, it follows that the prevalency of the disease in humans would be in countries with the highest consumption of raw or undercooked seafood--the Netherlands, Japan, specific areas in the U.S., and the Pacific coast of South America.

What are the most common sources of infection in those endemic countries?

The Netherlands--"green herring" (raw or slightly salted herring)

Japan--sashimi (raw fish) and sunomono (pickled fish)

South America--ceviche (lightly marinated, raw fish)

America--SUSHI!!!

Considering the increasing popularity of sushi in the U.S., anisakiasis will slowly become a common disease over time if the proper precautions are not taken.