建構臺灣產蚊成蟲數位影像資料庫暨硼酸溶液產卵桶實務應用

Abstract

蚊蟲是重要的醫學昆蟲，不僅滋擾人的生活更會傳播疾病，造成公共衛生問題。實習期間參與國家蚊媒傳染病防治研究中心 (簡稱：國家蚊媒中心) 之蟲原飼育、蚊媒密度調查與防疫工作，合計滿 200 小時。另於臺大公衛院蟲媒傳染病實驗室執行兩個研究，以下依目標分別論述。目標一：建構臺灣產蚊成蟲數位影像資料庫。臺灣已有紀錄的蚊種共16屬132種，傳統蚊種鑑定依照核對檢索表，但分類圖片因缺乏實體影像較不易理解，恐因誤差產生錯誤。本研究以數位影像技術拍攝蚊成蟲之分類鑑定特徵，並參考臺灣蚊種檢索之分類描述，建構蚊種數位資料。本資料庫重新編排臺灣蚊種檢索之文字，拍攝16屬109種蚊成蟲標本與實體彩色顯微分類圖片，及10屬25種常見或具傳病能力之蚊成蟲活體照。本研究為臺灣缺乏之系統性整理資料，可提供蚊媒防疫工作人員及民眾直接清楚辨識蚊種之工具，具實務應用價值。目標二：野外實地應用硼酸溶液產卵桶。產卵桶主要用於監測登革病媒蚊密度，兼具靈敏、被動監測及成本低廉之優點，但缺點為未妥善管理易成為孳生源。硼酸溶液產卵桶 (簡稱：硼酸桶) 以產卵桶改裝，將清水置換成1%硼酸溶液並襯入厚質不織布以提供蚊蟲產卵介質及吸附硼酸溶液使其吸食。硼酸桶於實驗室、小規模野外試驗確認具有滅殺蚊幼蟲與成蟲之功能，但缺乏長期野外實地評估。本研究於南部登革熱風險區佈設硼酸桶以進行長期評估，每兩週調查一次，並與國家蚊媒中心之產卵桶資料比較，以評估硼酸桶對登革病媒蚊之監測與防治成效。野外試驗合計於臺南、高雄佈設84個硼酸桶，自106年8月至107年10月之監測結果顯示：硼酸桶蚊卵平均陽性率為54.0% (n=1309，範圍：20.5-89.2%)，平均產卵數26±53.7顆，卵粒經聚合酶連鎖反應檢測以確認桶具誘集之蚊種，合計埃及斑蚊46.2% (n=265)、白線斑蚊38.9% (n=223)、兩者共存14.8% (n=85)，所有桶具均無蚊幼蟲孳生。鄰近對照之產卵桶蚊卵平均陽性率為59.6% (n=904，範圍：4-91.7%)，平均產卵數35.8±75.5顆，蚊卵經孵化以形態學鑑定，合計埃及斑蚊59.1% (n=395)、白線斑蚊31.3% (n=209)、兩者共存9.6% (n=64)，蚊幼蟲陽性率及平均蚊幼蟲孳生數為20.0% (n=210，範圍：0-66.7%) 及5.4±20隻。本研究於野外環境驗證硼酸桶可監測病媒蚊密度且不易形成孳生源，具防治應用價值。

Mosquitoes play important role in medical entomology. They not only annoy human but also transmit diseases that would cause public health concerns. In practice period, student participate routine work in National Mosquito-Borne Diseases Control Research Center (NMBDCRC) over 200 hours. There are two objectives in this study which is conduct in Vector-borne Infectious Diseases Laboratory, NTU. The first objective is to construct digital database of adult mosquitoes in Taiwan. Sixteen genera, 132 species of mosquitoes have been recorded in Taiwan. Due to the difficulty of morphological identification by traditional pictorial key, this study aims to renew the identification figures into digital photos in the book entitled ‘Pictorial Keys to the Mosquitoes of Taiwan’ for more accurate identification. This study took morphological photos of mosquito specimens from 16 genera, 109 species. Moreover, ecological pictures of common vector mosquitoes from 10 genera, 25 species were recorded. In conclusion, pictorial keys with digital photos can become useful tools for pest control workers to identify mosquitoes. The second objective is to apply the ovitrap with boric acid solution (BA trap) in the field. Ovitrap is a mosquito surveillance tool that has the advantages of sensitive, passive surveillance, inexpensive, and commonly used in monitoring density of dengue vectors. However, traditional ovitrap (TA trap) has the disadvantage of becoming potential mosquito breeding sites without careful management. BA trap was modified from TA trap by replacing water into 1% boric acid solution, and attaching thick non-woven fiber to the inner surface which can provide substrate for mosquito laying eggs and absorbing boric acid solution. Previous studies showed BA trap could successfully kill mosquito larvae and adults in laboratory and small scale field trial. This study aims to conduct long-term field trial of BA trap, and to compare with TA trap managed by NMBDCRC at the hotspots of dengue fever - Tainan and Kaohsiung. This study set up 84 BA traps in Tainan and Kaohsiung and monitor every two weeks with over-1-year surveillance. Species of mosquito eggs were identified using PCR in trial of BA traps, and using morphological identification after hatching in trial of TA traps. Results showed that the positive rate of Aedes eggs in BA and TA traps were 54% (n=1309, range: 20.5-89.2%) and 59.6% (n=904, range: 4-91.7%), and average number of eggs were 26.0±53.7 and 35.8±75.5, respectively. The positive rate of Aedes larvae in BA and TA traps were 0 and 20.0% (n=210, 0-66.7%), and the average number of larvae were 0 and 5.4±20.0, respectively. The proportion of Aedes species in BA and TA traps were Ae. aegypti (46.2%, n=265), Ae. albopictus (38.9%, n=223), mix (14.8%, n=85), and Ae. aegypti (59.1%, n=395), Ae. albopictus (31.3%, n=209), mix (9.6%, n=64), respectively. In conclusion, BA traps have the ability of monitoring Aedes density without becoming mosquito breeding sites in the field. BA traps are worth to promote.