Anisakiasis caused by herring in vinegar: a little known medical problem.

Six cases of intestinal anisakiasis, or herring worm disease, diagnosed over a two year period in a Belgian gastroenterology unit are described. They presented mainly as intestinal obstructions and larvae of this marine nematode were found in the intestinal wall of two of the four patients who were operated on. In two other patients awareness of the diagnosis permitted conservative treatment and spontaneous healing. In five patients symptoms developed after they had eaten herring marinated in vinegar, a hitherto little known source of the herring worm disease.