A History of Research into Gastric Anisakiasis in Japan

Abstract

Progress in research into gastric anisakiasis in Japan has developed more slowly than research into intestinal anisakiasis. Remarkable and rapid progress, however, has been achieved since 1968 when endoscopic examination allowed the observation of Anisakis larvae penetrating the gastric wall and removal and direct identification of the worm. Previously, gastric anisakiasis could only be diagnosed when dead worms and/or their cross sections were histopathologically observed inside granulomas with eosinophilic cell infiltration in the resected stomach. Although the presence of granulomas with eosinophilic cell infiltration in the stomach had been known since the 1950s, Asami et al. [1] confirmed the relation between them and the infection of Anisakis larvae in 1964. Their work resulted in the establishment by the Ministry of Education of a research group in 1965 concerned with parasitic granulomas, which was headed by Ohtsuru. In addition, many cases of granulomas with eosinophilic cell infiltration caused by Anisakis larvae in the stomach have been reported since 1967. However, it roved difficult to confirm gastric anisakiasis by the conventional method of endoscopie biopsy because the granulomas were too small. This was also found to be the case when granulomas were biopsied with the endoscopie incision method for the submucosal tumors using an electric high-frequency wave. Therefore, the most reliable method seemed to involve obtaining large tissue specimens by jumbo-biopsy.