Investigation of seroprevalence and transmission routes for Paragonimus westermani infection in sika deer

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K08082
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Veterinary medical science
• Research Institution: University of Miyazaki
• Principal Investigator: Yoshida Ayako 宮崎大学, 農学部, 教授 (20343486)
• Co-Investigator(Kenkyū-buntansha): 長安 英治 宮崎大学, 医学部, 助教 (20524193)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: ウェステルマン肺吸虫症 / ニホンジカ / 抗体検査 / 待機宿主 / ジビエ

Outline of Final Research Achievements

Seroprevalence of Paragonimus infection in sika deer was evaluated to assess the risk of paragonimiasis through venison consumption. Total 1,546 blood samples collected from sika deer from February 2013 to March 2020 in western Japan were tested by pre-adsorbed ELISA, and 1.4 % of them were positive for anti-Paragonimus antibodies. Our results suggested that venison can be a risk of the infection in the endemic areas of paragonimiasis, although the infection risk of venison would be lower than that of wild boar meat considering the positive rate in wild boars in these areas (9.1-43.0%). In addition, the leg of Japanese freshwater crab, Geothelphusa dehaani, was found in the rumen of sika deer, suggesting sika deer got Paragonimus infection by the ingestion of Japanese freshwater crab, the first intermediate host.

Free Research Field

寄生虫学

Academic Significance and Societal Importance of the Research Achievements

本研究により、ニホンジカはウェステルマン肺吸虫に感染した第2中間宿主のサワガニを摂食することで肺吸虫に感染し、待機宿主として筋肉内に幼若虫を保有して、ヒトへの感染源となることがわかった。また、シカ肉からのウェステルマン肺吸虫への感染リスクは、イノシシ肉に比べ低いと推察されたものの、肺吸虫に感染しているとみられるニホンジカは肺吸虫症の流行地域に広く分布していることを明らかにした。これらの成果は、寄生虫学上の新しい知見であるとともに、食の安全性確保や公衆衛生の向上に貢献することが期待できる。