Larval forms of nematodes of the Anisakidae family (cod or herring worms) can cause disease in people who eat raw or undercooked seafood. These nematodes are widespread along the eastern and western coasts of the United States, and the larvae can be found in fresh fish sold in any grocery store. Luminal infestation causes few symptoms. Invasive anisakiasis may be acute or chronic and may involve the stomach or the small intestine.