2012至2014年臺灣地區豬流行性下痢病毒之檢測與序列分析

Detection and sequence analysis of PEDV in Taiwan from 2012 to 2014.

吳懷軒(Huai-Hsuan Wu)

指導教授 ： 林昭男 ； 邱明堂

國立屏東科技大學/農學院/獸醫學系所/碩士(2014年)

https://doi.org/10.6346/NPUST.2014.00289

摘要

豬流行性下痢病毒 (Porcine epidemic diarrhea virus, PEDV) 是豬流行性下痢 (porcine epidemic diarrhea, PED) 之致病原，可感染所有年齡豬隻，哺乳仔豬感染此病後死亡率極高，造成養豬產業重大經濟損失。近年來PED已陸續在多個國家爆發，而臺灣地區於2013年底亦開始出現PEDV的爆發，並尚未有相關文獻之探討。本研究以現有之傳統PCR引子對，搭配針對PEDV設計之特異性核酸探針進行即時聚合酶鏈鎖反應(real-time PCR)以篩檢2012年至2014年間共686例下痢豬隻樣本，其中共有279例為陽性，各年樣本數及陽性率為2012年：1/47 (2.12%)、2013年：7/123 (5.69%)、2014年：271/514 (52.72%)。並針對陽性樣本進行病毒之部分S基因序列分析，比對結果顯示近期爆發的病毒株與2013美國病毒株具有較高的相似度 (99.1%-100%)，根據序列分析結果推臺灣本次爆發之病毒可能來自美國，並比較同一豬場不同時間之檢體序列發現，A豬場於2014年1月至5月間送檢之5例檢體間相似度為99.2~99.7%，顯示場內為同一病毒株感染，而B場於2013年10月及2014年2、4月及5月送檢之4例檢體，2013年檢體與2014年檢體相似度為97.1~97.4%，而2014年3例檢體間相互相似度為99.2~99.7%，並且前者與中國病毒株LBJ/03相似度較高 (99.1%)，後者則與美國病毒株相似度較高 (99.5%)，顯示場內為兩株不同病毒感染，因此不同病毒株間交叉保護力不佳，臺灣尚無疫苗研發等研究，因此目前處置方式均以反飼來進行免疫，但反飼有導致場內潛在疾病爆發及病毒於場內反覆感染之風險，因此如何有效控制疫情的發生為未來重要課題。

關鍵字

豬流行性下痢病毒 ； 即時定量聚合酶連鎖反應 ； 序列分析

並列摘要

Porcine epidemic diarrhea virus (PEDV) is a causative agent of porcine epidemic diarrhea (PED) which can infect swine in all ages and is lethal in piglet infection, causing huge economic loss. Althought PEDV outbreak in many countries had been reported, outbreak in Taiwan was first confirmed in the end of 2013. Real-time PCR with specific probe was used to screen intestinal and fecal samples from 2012 to 2014, and the positive rate in Taiwan were 1/47 (2.12%), 7/118 (5.93%) and 271/514 (52.72%) in 2012, 2013 and 2014, repectively. The partial S gene of positive samples were sequenced and analyzed. The sequenced S gene of Taiwan strain shared high similarity with that of 2013 USA strains (99.1%-100%) indicating the strain may come from USA. The sequences from five cases in farm A from January to May 2014 shared 99.2~99.7% similarity, whereas the sequences from farm B in Oct, 2013 to May, 2014 shared only 97.1~97.4% of similarity. The sequences form farm B in Feb, Apr and May, 2014 shared 99.2~99.7%. The former shares 99.1% of similarity with that of China strain LBJ/03 and later shared 99.5% with that of 2013 USA strain. Moreover, the above-described results showed the farm A was re-infected with the virus strain identified in the same farm whereas farm B was re-infected with different virus strains. Because of the weak cross reaction between different viral strains and the lack of vaccine development, feedback treatment to induce immune-responses is widely used. However, feedback treatment may induce other diseases and the subsequent risk of repeated re-infection of PEDV. Therefore, to development effective strategies based on Taiwanese strain is crucial for the control and prevention of PED in the future.

並列關鍵字

Porcine epidemic diarrhea virus ； Real-time PCR ； Sequence analysis

參考文獻

Bosch BJ, van der Zee R, de Haan CAM, and Rottier PJM. The Coronavirus Spike Protein Is a Class I Virus Fusion Protein: Structural and Functional Characterization of the Fusion Core Complex. Journal of Virology 77: 8801-8811, 2003.

Chae C, Kim O, Choi C, Min K, Cho WS, Kim J, and JH T. Prevalence of porcine epidemic diarrhoea virus and transmissible gastroenteritis virus infection in Korean pigs. The Veterinary Record 147: 606-608, 2000.

Chen J, Wang C, Shi H, Qiu H, Liu S, Chen X, Zhang Z, and Feng L. Molecular epidemiology of porcine epidemic diarrhea virus in China. Archives of Virology 155: 1471-1476, 2010.

Chen JF, Sun DB, Wang CB, Shi HY, Cui XC, Liu SW, Qiu HJ, and Feng L. Molecular characterization and phylogenetic analysis of membrane protein genes of porcine epidemic diarrhea virus isolates in China. Virus Genes 36: 355-364, 2008.

Chen Q, Li G, Stasko J, Thomas JT, Stensland WR, Pillatzki AE, Gauger PC, Schwartz KJ, Madson D, Yoon KJ, Stevenson GW, Burrough ER, Harmon KM, Main RG, and Zhang J. Isolation and characterization of porcine epidemic diarrhea viruses associated with the 2013 disease outbreak among swine in the United States. Journal of Clinical Microbiology 52: 234-243, 2014.