金傳春2006-07-252018-06-292006-07-252018-06-292004-07-31http://ntur.lib.ntu.edu.tw//handle/246246/47012002 年台灣爆發生近六十年最嚴重的一次登革出血熱流行，重症與死亡病 例數創歷年新高，且登革出血熱的致死率高達8.7%，此波流行病學的重要性值 得深入探討。本研究目的是探討致禍的第二型登革病毒在分子層次上的變異，分 析台灣第二型登革病毒全長外套膜(envelope)基因1485 核苷酸序列的歷年趨變。 做法是自2001 至2003 年登革病人血中分離出的第二型登革病毒30 株進行 E 基因序列全長的比對，發現其有高達99.1%~100%的同質性，仔細分析知2001 年的8 株、2002 年20 株與2003 年兩株的相似度各為99.6%~100%、99.5%~100% 及99.7%,相似性相當高。又以1981 年的第二型登革病毒株之E 基因序列為基 準，相較於1987 、1997 、2001~2003 年所得的此型病毒E 基因序列之相似度由 95.3%已降至各為94.4%與92.6%。演化樹比較發現：(1)台灣的第二型登革病毒 有兩群(0%~8.7%變異)，分別為都會型基因型別與亞洲第二基因型別；(2)2001 與2002~2003 年可以清楚區分兩個明顯的分支，在核苷酸位置137 、291 、1128 上由2001 年8 株的C 、A 、T ，至2002-2003 年的22 株已被取代成T(其中一株 仍維持C)、T 、C ，而氨基酸位置46 是由2001 年的酥胺酸(T)被2002 年取代為 異白胺酸(I)，即隨著流行時間拉長而基因序列上有一致性變化；(3)有趣的是2001 年與2002 年均可看出自屏東縣東港鎮的第二型登革病毒株是和其他高雄縣/市、 屏東市所分離的第二型登革病毒株有較遠的親源關係，顯示環境的不同與流行的 密度會影響病毒演化的速率，或是在不同的選擇壓力下易有不同的演化方向；及 (4)此台灣第二型登革病毒也屬於都會型(cosmopolitan)基因型別，與1998 年自泰 國、2002 年自緬甸、2003 年自越南的第二型登革病毒株不同。 綜述此都會基因型的第二型登革病毒依流行時間拉長而產生一致性變 化，且在不同地區的相同環境下病毒E 基因序列相近。由於經費侷限性，未來 將比較此病毒分子變異群(quasispecies)的變化差異何在及其與宿主之間的關係。The largest epidemic of dengue hemorrhagic fever (DHF) with the highest morbidity, mortality, and case fatality rate (CFR ：8.7%) in recent sixty years exploded in southern Taiwan in 2002, since 1942. The causing agent of this DHF epidemic was primarily due to dengue virus serotype 2 (DENV-2). How could the different isolates of DENV-2 change over years in Taiwan is very important to be understood. We investigated the molecular changes of viral factors in this epidemic in KaoHsiung City/County and Pingtung City/County during 2001-2003 by elucidating the molecular changes in nucleotide and amino acid sequences of complete envelope (E) gene (1485 nucleotides) of DENV-2 through collecting the viral isolates obtained from 2001-2003 compared with those from past epidemics in Taiwan and other countries from GenBank through phylogenetic and qualitative analyses. To determine the role of viral evolution in emerging a large-scale epidemic of DHF during 2001-2003, we analyzed the complete sequences of E gene of 38 DENV-2 isolates obtained from epidemics in 1981, 1987, 1997, and 2001-2003 in Taiwan. The maximum-likelihood phylogenet tree analysis revealed that Taiwan's DENV-2 isolates fell into 2 clusters (diversity 0~8.7%). The 2001-2003 ’s DEN V-2 isolates, which belonged to the cosmopolitan genotype, showed 99.1%~100% sequence identity and 8, 20 and 2 DENV-2 isolates of 2001, 2002 and 2003 had 99.6-100%, 99.5-100% and.99.7% homology, respectively. The 1981's DEN V-2 isolate had 95.3 % nthomology with 1987's and such an identity dropped to 94.4% in 1997, and declined to 92.6% in 2001-2003. The nucleotide sequences of E gene at positions of 137,291,1128 of 2001's eight DEN V-2 isolates had consistent changes from C, A, T to T (only one remained as C), T, C in 2002-2003's twenty-two isolates whereas the amino acid at position 46 was consistently changed from Thr in 2001 to I lein 2002 as the epidemic became longer.Tungkang's DEN V-2 isolates showed geographic differences from Kaohsiung's DEN V-2 isolates in both 2001 and 2002, implying different environmental factors or selective pressures affecting various evolution rate or directions of DENV-2. Unfortunately, there were no molecular signatures of distinct lineage for those isolates from DHF vs. DF or dengue cases with or without specific underlying diseases. In summary, the Cosmopolitan genotype of DENV-2 came into Taiwan in 2001 and increased its diversity in 2002-2003 plus geographical variation taken together had facilitated to emerge more variants of DENV-2. Therefore, future studies on quasispecies of DENV-2 in host with different conditions and investigate pathogenesis of DHF between virus evolution and alternating hosts through transmission chains.application/pdf542959 bytesapplication/pdfzh-TW國立臺灣大學公共衛生學院流行病學研究所[SDGs]SDG3reporthttp://ntur.lib.ntu.edu.tw/bitstream/246246/4701/1/922320B002165.pdf