圖書典藏及影音數位平台

(100年) 1月間，有民眾在石門水庫後池堰下游大漢溪水域垂釣，發現漁獲中俗稱溪哥之平頜?全身長滿黃色泡狀物，經檢驗分析，確認係遭俗稱黃吸蟲(yellow grub)之複殖吸蟲－扁彎口吸蟲(Clinostomum complanatum)囊狀幼蟲感染。復經多次採樣調查，初步發現前述水域溪哥之感染情況如下：感染盛行率(Prevalence)：81.82%，平均感染強度(Mean intensity)：18.7 個囊幼/魚，平均豐富度(Mean abundance) 15.3個囊幼/魚。檢視庫區9種魚類標本各1尾，皆未發現吸蟲感染。集水區之三民溪檢出扁彎口吸蟲囊幼感染，對象包括苦花、石 與溪哥，其盛行率、平均感染強度和平均豐富度分別為：苦花 100%, 64.3, 64.3；石 83%, 6.6, 5.5；溪哥100%, 14.0, 14.0。相關結果已載明於本局局之報告書「石門水庫下游大漢溪水域魚類爆發感染寄生蟲疫病檢測分析報告」。 由於前述遭感染之溪哥最嚴重者其體內有逾百隻囊幼，除分布於口腔和皮下組織外，體表亦清晰可見黃色泡狀物，以致民眾緊張驚恐，而部分傳媒則以諸如 「石門水庫活魚三吃陷危機」、「石門恐怖腫瘤魚 長滿百隻寄生蟲」等聳動標題報導此事，益增社會不安且對石門活魚產生疑慮，同時亦指控主管當局管理水庫不當，因污染以致滋生此寄生蟲。 為釐清此問題，初步已確認魚體病原固為人畜共通性(zoonosis)，但並非導染人類肝炎、肝硬化甚至肝癌之中華肝吸蟲，而是罕有病例之扁彎口吸蟲。而根本釐清之道則需兼採科學方法之雙重研究策略：(1) 以調查科研(discovery science)持續監控集水區、庫區與後池堰附近水域魚類感染扁彎口吸蟲之疫情，並查明其生活史；同時擬擴大檢測對象，包涵台灣已為其疫區之中華肝吸蟲。 (2) 以假說為基礎之科研(hypothesis-based science)，經人工感染實驗，驗證庫區放養魚類是否可為此吸蟲之中間寄主。

Fish and snail samples were smoothly collected from five Digenean outbreak monitoring areas in the Shihmen Reservoir including three sites located in watershed, reservoir and downstream during March 11th 2013 to December 15th 2014. Eight fish species were found to be infected by metacercariae of Clinostomum complanatum, also known as yellow grub: Taiwan striped barb (Acrossocheilus paradoxus), crucian carp (Carassius auratus), common carp (Cyprinus carpio), Amur barbel (Hemibarbus labeo), Taiwan shoveljaw carp (Onychostoma barbatula), Formosan stripe dace (Zacco barbata) and freshwater minnows (Z. pachycephalus and Z. platypus). All these fish species could act as the second immediate hosts of this fluke. New host records were reported from them but common carps and crucian carps. In addition, Clonorchis sinensis metacercariae were never recovered from fish samples examined. Yellow grubs usually remained inside fish’s subcutaneous tissues except Taiwan striped barb whose deep muscles had been heavily infected. Clinostomoid cercariae had been recovered from Taiwan big-ear radix, Redix swinhoei, among 6 snail species examined. The role of the first immediate hosts of this fluke had been confirmed. Specific primer pairs had been designed based on 18S rDNA sequences of Clinostomum complanatum. A fragment of 404 bp was amplified by polymerase chain reaction; its specificity was confirmed after sequencing and sequence alignment. These protocol is applied for molecular prospecing of mass screening for C. complanatum infections in snail samples.