Novel liver fluke species causing human illness in Ecuador: Prevalence, morphological and genetic identification, and infection sources

2015 Fiscal Year Final Research Report

• Project/Area Number: 25305011
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 海外学術
• Research Field: Parasitology (including sanitary zoology)
• Research Institution: National Institute of Infectious Diseases
• Principal Investigator: Sugiyama Hiromu 国立感染症研究所, その他部局等, その他 (00145822)
• Co-Investigator(Kenkyū-buntansha): Kumazawa Hideo 高知大学, 医学部, 助教 (70127942)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: 肝吸虫 / Amohimerus / 肺吸虫 / Paragonimus / エクアドル / 人獣共通感染症 / 食品媒介感染症 / 伝搬生態学

Outline of Final Research Achievements

The geographical distribution, prevalence, and intermediate hosts of the liver fluke belonging to the genus Amphimerus were investigated in Ecuador. Endemic areas were found in 3 provinces in the Pacific Coast. More than 20 species of the freshwater fish were examined for metacercariae. Small fishes called Guabina, which are highly prevalent in the small streams flowing along the villages, were found to be the most important sources of infection in humans. This fish species recorded a high number of metacercariae per fish. We analyzed the sequence of ribosomal ITS2 DNA from adult Amphimerus flukes discharged by patients after praziquantel treatment, and utilized it as a marker to identify the metacercariae of this species in fish. A literature review was also conducted on lung flukes to summarize the status of the disease, paragonimiasis caused by Paragonimus mexicanus.

Free Research Field

寄生虫学