Do kuoid myxozoans showing symptomatic infection cause foodborne diseases? - Elucidation of the diarrheagenicity and the mechanism of diarrhea -

2021 Fiscal Year Final Research Report

• Project/Area Number: 17K07954
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Aquatic life science
• Research Institution: Osaka Institute of Public Health
• Principal Investigator: Kawai Takao 地方独立行政法人 大阪健康安全基盤研究所, 微生物部, 課長 (30250319)
• Co-Investigator(Kenkyū-buntansha): 横山 博 岡山理科大学, 獣医学部, 教授 (70261956)
• Project Period (FY): 2017-04-01 – 2022-03-31
• Keywords: Kudoa iwatai / 下痢原性 / 食中毒 / 顕性感染 / 粘液胞子虫

Outline of Final Research Achievements

Kudoa iwatai, showing a symptomatic infection in Japanese seabass and yellowfin seabream etc., has been suspected as a causative agent of foodborne diseases. In this study, we estimated the diarrheagenicity of K. iwatai using experimental animals (suckling mice). As a result, K. iwatai was found to have the diarrheagenicity, as well as K. septempunctata, which is the only myxosporean parasite proven to cause foodborne diseases. Electron microscopic analyses and gene expression analyses by DNA microarray of intestinal tracts of the mice inoculated with K. iwatai spores suggested that the mechanism of diarrhea might be due to intestinal epithelial damage caused by their polar filaments extruded from spores.

Free Research Field

食品微生物学

Academic Significance and Societal Importance of the Research Achievements

キチヌやスズキ等に寄生する顕性感染型のK. iwataiは、不顕性感染型であるナナホシクドアよりも多い胞子数を必要とするものの、ナナホシクドアと同様に下痢原性を示した。その機序もナナホシクドアと似ていたことは、K. iwataiは食中毒を起こすことができると考えられた。本成果は、顕性感染型であっても粘液胞子虫であるならば、食中毒を起こす可能性があることを示唆するものであり、学術的にも公衆衛生学的にも意義は高い。