淡水螺螄尾動幼蟲之感染研究

Infectivity Study of The Cercaria From Freshwater Snails

許勤郁(CHIN-YU HSU)

指導教授 ： 李明憲

中臺科技大學/健康科學院/醫學檢驗生物技術系碩士班/碩士(2018年)

摘要

吸蟲(Trematode, fluke)屬於扁形蠕蟲門吸蟲綱之寄生蟲。吸蟲之生命週期通常會有一至兩個中間宿主；包括軟體動物之淡水螺螄、脊椎動物之魚類、甲殼動物或水生植物等。而大多數的淡水螺螄可能成為寄生蟲感染人類及脊椎動物的中間宿主，然後進一步發育。本研究目的主要是想探討淡水螺螄體內尾動幼蟲之感染率，進行型態學觀察以及分子生物學上的鑑定。從2015年七月至2017年四月期間，分別在大里溪、大坑溪、頭汴坑溪三條河流以隨機抽樣的方式採集不同種類之淡水螺螄。藉由光照法及人工壓碎法使尾動幼蟲釋出，在光學顯微鏡下進行觀察。並將收集到的尾動幼蟲進行DNA萃取及以非特異性引子進行聚合酶連鎖反應，將PCR產物送至定序後進行NCBI blast之物種鑑定。我們總共採集1356隻淡水螺螄，其中台灣椎實螺389隻、瘤蜷808隻、圓田螺95隻、石田螺51隻、川蜷13隻。尾動幼蟲總感染率為4.20%，其中台灣椎實螺尾動幼蟲感染率為4.63%、瘤蜷4.83%，而圓田螺、石田螺以及川蜷為0%。經統計結果分析後，螺螄之長度及感染率並沒有顯著差異。然而頭汴坑溪與大坑溪螺螄兩條溪流之間螺螄尾動幼蟲盛行率有顯著性差異(p<0.005)；頭汴坑溪與大里溪螺螄兩條溪流之螺螄尾動幼蟲盛行率有顯著性差異(p<0.001)。從淡水螺螄分離出三種類型之尾動幼蟲，劍尾類、矛口類及叉尾類尾動幼蟲。經分子技術鑑定出六種吸蟲尾動幼蟲，包括扁彎口吸蟲 (Clinostomum complanatum)、台中異形吸蟲 (Haplorchis taichui)以及台灣異形吸蟲 (Centrocestus formosanus)。另外還有三種寄生蟲尚未確認，包括Paralecithodendrium longiforme、Lecithodendriidae sp.以及Collyriclum faba，之後會再進一步進行分析。

關鍵字

吸蟲 ； 尾動幼蟲 ； 淡水螺螄

並列摘要

Trematodes are an important pathogen of medicine and veterinary. Their life cycle usually has one or two intermediate host; include freshwater snail, fish or crab and others. Most freshwater snails can become intermediate hosts that may infect to humans and animals, and then further development.Freshwater snails were collected from different species during July, 2015 to April, 2017. The cercariae were obtained by lighting or/and crushing methods under optical microscope from snails. Cercariae were used to DNA extraction and sequencing for species identification. A total of 1,356 freshwater snails, representing five species, were examined for shedding cercariae. 389 Radix swinhoei, 808 Tarebia granifera, 95 Cipangopaludina chinensis, 51 Cipangopaludina miyagii, and 13 Semisulcospira libertina were collected and examined. The average prevalence rate of cercariae infection was 4.20%, including R. swinhoei 4.63%, T. granifera 4.83%, C. chinensis 0%, C. miyagii 0% and S. libertina 0%, respectively. The statistics results showed that there was no significant difference between infection rate and length in all snails. However, Prevalence was a significant difference between Toubiankeng river and Dakeng river (p<0.005), between Toubiankeng river and Dali river (p<0.001). Highest prevalence of cercariae infection of freshwater snails in the Toubiankeng river among the three streams, while T. granifera is the highest prevalence of infection in all freshwater snail. Three types of cercaria were found. Six different species were isolated with molecular technology. We found three types cercariae, including Clinostomum complanatum, Centrocestus formosanus, and Haplorchis taichui from freshwater snails. There are three parasites that have not identified, including Paralecithodendrium longiforme, Lecithodendriidae sp., and Collyriclum faba, before further analysis.

並列關鍵字

trematode ； cercariae ； freshwater snail

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