- 學位論文
臺灣嘉南地區田間小型哺乳類動物及其外寄生跳蚤媒介立克次體和巴通氏菌之檢測
Detection of Rickettsia spp. and Bartonella spp. in fleas and small mammals in Chiayi and Tainan area in Taiwan
摘要
農地生態系常見小型哺乳動物包括囓齒類和鼩鼱類，種類繁多且扮演陸域生態系中重要角色，更常被視為環境品質之指標物種。其繁殖力強、可能傳播病原體和媒介受病原體感染之外寄生蟲等特性易造成農業經濟和公共衛生之危害，因此需落實鼠類相關防治與長期監測工作。臺灣過往為防範野鼠啃咬所造成的農損，因而訂定「滅鼠週」，採用農地定期施放毒餌滅鼠之策略，以達到降低鼠類族群數量之目的。然而，使用滅鼠藥所造成的二次毒害事件頻傳，例如猛禽死亡等，行政院農業委員會動植物防疫檢疫局遂於2015年取消滅鼠週活動。有鑑於小型哺乳類動物之族群增長與疾病傳播風險，需定期分析其相關病原體，以建立預警機制。2019至2020年間，於嘉義的鹿草鄉和義竹鄉、台南的鹽水區和學甲區等四個地點，以含食餌之捕鼠籠誘捕，每二個月捕捉一次。所採集之小型哺乳類動物以形態和分子方法進行鑑定，並透過分子檢驗分析外寄生蟲跳蚤和小型哺乳類動物脾臟檢體所攜帶病原體之狀況。調查期間總計捕獲302隻共七種小型哺乳類動物，收集274個鼠脾臟檢體及外寄生跳蚤共有160隻。利用聚合酶鏈鎖反應 (Polymerase Chain Reaction; PCR) 分別增幅立克次體 (rickettsiae) 之檸檬酸合成酶基因 (gltA)、體表蛋白基因 (ompB)，巴通氏菌 (bartonellae) 之檸檬酸合成酶基因 (gltA )、RNA聚合酶β亞基 (rpoB)、細胞分裂蛋白基因 (ftsZ)，以及無形體科 (Anaplasmataceae) 之16S rDNA、23S-5S之內轉錄間隔區 (23S-5S ITS)。鼠蚤蟲體及鼠脾檢體未偵測到立克次體(Rickettsia spp.)；鼠蚤和鼠脾感染巴通氏菌之陽性率分別為78.75% (126/160) 及19.3% (53/274)。使用限制性片段長度多態性分析 (PCR-RFLP)，鑑別出五類群巴通氏菌有Bartonella rochalimae-like、B. tribocorum-like、B. elizabethae-like、B. queenslandensis-like和 Bartonella spp. 等；鼠蚤與鼠脾攜帶無形體科之陽性率分為41.25 % (66/160) 及26.6% (73/274)。研究結果顯示，於鼠蚤及鼠脾中均檢驗出Bartonella rochalimae-like，陽性率分為59.5% (75/126) 及7.5% (4/53)。透過定期野鼠調查與病原體檢測以提供相關資料，有助於未來訂定政策及鼠媒疾病防治策略。
並列摘要
Small mammals in farmland include rodents and shrews, which play major ecological roles of contributing to the ecosystem diversity and consuming plant material and invertebrates. However, small mammals may carry pathogens and are considered important reservoirs of zoonotic diseases. Moreover, they harbor hematophagous ectoparasites serving as vectors of pathogens, such as fleas. Due to their high reproduction rate and rodent-borne diseases that impacted the agricultural economy and public health, the Taiwan Bureau of Animal and Plant Health Inspection and Quarantine (BAPHIQ) used to promote chemical controls to poison small mammals in fields, called the nationwide campaign of the anti-rodent week. To reduce the environmental impact of rodenticides, this campaign had been stopped since 2015. Nevertheless, there is a concern about their proliferation due to a perceived reduction in rodent control efforts. A long-term surveillance program to monitor the population of small mammals, fleas, and the associated pathogens is essential after the cessation of the relevant rodent control measures. In this study, small mammals were captured by using live traps with baits in agricultural fields including Yijhu Township and Lucao Township of Chiayi County and Xuejia District and Yanshui District of Tainan City from 2019 to 2020 bimonthly. A total of 274 spleen samples and 160 fleas from 302 small mammals (seven species) were investigated for potential pathogens including the genera of Rickettsia and Bartonella and Anaplasmataceae by Polymerase Chain Reaction (PCR). Rickettsia spp. were not detected in fleas and spleen samples, using the gltA gene and the ompB gene. Bartonella spp. were detected in 78.75% (126/160) of fleas and 19.3% (53/274) of spleen samples, using the gltA gene, the ftsZ gene, and the rpoB gene. Bartonella rochalimae-like, B. tribocorum-like, B. elizabethae-like, B. queenslandensis-like, and Bartonella spp. were detected, using PCR-RFLP analysis. Besides, 59.5% (75/126) of fleas and 7.5% (4/53) of small mammals carried B. rochalimae-like. Anaplasmataceae was detected in 41.25 % (66/160) of fleas and 26.6% (73/274) of spleen samples, using 16S and ITS-23S-5S genes. Periodic investigations of wild small mammals and pathogenic detections are important for the prevention of rodent-borne disease, providing data to formulating effective strategies of prevention and control in the future.