臺灣博碩士論文加值系統

發熱伴血小板減少綜合症(SFTS)為一透過壁蝨媒介且伴隨高死亡率的人畜共同傳染病。發熱伴血小板減少綜合症病毒(SFTSV)可感染廣泛的動物種類，包括綿羊、牛、狗、雞和其他野生動物。自第一起病例於2010年在中國被報導後，SFTS報告即迅速擴增至中國23個省份並出現超過9000名人類感染的病例。除此之外，日本和南韓也相繼於2012年宣布成為有SFTS發生的國家，並在東亞地區引起極大關注。目前在台灣並未有SFTS在人或是動物等相關報告或病例出現。然而，台灣在地理位置上鄰近SFTS流行國家，這點讓台灣暴露於SFTS入侵的高潛在風險。本研究旨在瞭解SFTSV於台灣是否存在。樣本採集上，在南投縣及台中市共採集151個動物血清樣本，其中包含31隻綿羊、63隻牛、30隻收容犬隻及27隻家犬。檢測上，利用One-step RT-nested PCR及IgG ELISA來分別檢測SFTSV專一性RNA及抗體。結果顯示，僅有綿羊(12/30)可偵測出SFTSV專一性抗體；病毒核酸則於綿羊(9/31)及牛(3/34)樣本中皆可被偵測出。此外，病媒檢測上，採集到的360隻壁蝨均被鑑定為雌性Rhipicephalus microplus成蟲，並於RT-PCR檢測結果中有25 (9/36)的混合壁蝨樣本被檢測出陽性。綿羊、牛及壁蝨的陽性樣本序列分析顯示該病毒在這些物種間具有高度的相關性(95-100相似度)。親緣關係分析發現本研究中病毒之序列相較於日本及南韓更接近中國的病毒族群。總結以上，本研究證實在哺乳類及壁蝨檢測到SFTSV核酸與抗體陽性的證據，結果可揭示SFTSV在台灣的存在。因此，有關SFTSV在台灣的流行病學、宿主種類偏好及病媒與宿主間的致病機制有需要即刻接續進一步研究。

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging tick-born zoonosis with high mortality in human. SFTS virus (SFTSV) infects a wide range of animals including sheep, cattle, dogs, chicken and other wildlife. Since the first discovery in China in 2010, the SFTS case reports have rapidly spread through 23 provinces with more than 9000 human cases in China to date. In addition, Japan and South Korea were also found to be endemic countries in 2012, raising great concern in East Asia. In Taiwan, there was no report of SFTS on human or animals so far; however, the geographic closeness with endemic countries renders Taiwan at a high risk potential of SFTS appearance. To investigate the existence of SFTSV in Taiwan, a total of 151 serum samples from 31 sheep, 63 bovine, 30 shelter dogs and 27 companion dogs in Nantou county and Taichung city were collected. One-step RT-nested PCR and IgG ELISA were conducted to test SFTSV specific RNA and antibodies, respectively. The result indicated that SFTSV-specific antibodies were found in sheep (12/31), but not in bovine and canine. On the other hand, virus nucleotide was detected both in sheep (9/31) and bovine (3/34) but not in dogs. Furthermore, 360 adult female ticks, identified as Rhipicephalus microplus were examined by RT-PCR in which 25 (9/36) pooled groups showed positive results. The sequencing of the positive samples indicated that the virus was strongly (95-100 similarity) related between the mammals and the ticks. Phylogenetic analysis suggested closer sequence similarity to the China than to the Japan and South Korea clades. In conclusion, the positive results in mammals and ticks indicated the existence of SFTSV in Taiwan. Further study on the host preference and epidemiology in Taiwan and the vectors to host mechanism of SFTSV are warranted.

摘要 i
Abstract ii
目次 iii
表目次 v
圖目次 vi
Chapter 1. Introduction 1
Chapter 2. Literature Review 3
1.Genome and structure 3
2.Genetic diversity for SFTSV 4
3.Clinical signs of Severe Fever with Thrombocytopenia syndrome in human 5
4.Epidemiology 5
5.Host and the transmission vector 7
6.Diagnostic method of Severe Fever with Thrombocytopenia syndrome 9
7.Prevention 11
Chapter 3. Materials and Methods 12
1.Sample collection 12
2.Collection and morphological identification of ticks 12
3.SFTSV-specific IgG enzyme-linked immunosorbent assay (ELISA) 12
4.One-step RT-nested PCR 14
5.Complete blood cell count in bovine 15
6.Phylogenetic analysis 16
Chapter 4. Results 17
1.Optimization and accuracy of SFTSV-specific IgG ELISA 17
2.Detection of SFTSV-specific antibodies in mammals 17
3.Optimization of one-step RT-nested PCR 17
4.Detection of SFTSV RNA in mammals 18
5.Complete blood cell count in bovine 18
6.Collection and morphological identification of ticks 18
7.Detection of SFTSV RNA in ticks 19
8.Sequence alignment of partial S segment amplified from field samples 19
9.Phylogenetic analysis 19
Chapter 5. Discussion and Conclusion 20
1.The importance of the study 20
2.Sampling selection for SFTSV 20
3.Selection and optimization of detection methods 21
4.Detection of SFTSV in mammals 23
5.Comparison between PCR and ELISA result 23
6.Rhipicephalus microplus as a potential SFTSV vector in Taiwan 25
7.Phylogenetic analysis of SFTSV in Taiwan 26
8.Conclusions and Future Directions 27
Tables 29
Figures 32
References 45
Appendix 51

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