由離乳後淘汰豬隻組織中偵測豬鐵士古病毒

Detection of Porcine Teschovirus from Culled Postweaner Pigs

邱國詔(Kuo-Chao Chiu)

指導教授 ： 王汎熒

國立臺灣大學/獸醫專業學院/獸醫學研究所/碩士(2010年)

https://doi.org/10.6342/NTU.2010.10070

摘要

豬鐵士古病毒(PTV)為Picornaviridae科Teschovirus屬之無封套、大小約25-30 nm之單股正向RNA病毒。早期被歸類為Enterovirus，之後獨立為Teschovirus，並有至少11個血清型。鐵縣病( Teschen disease)最早於1929年於捷克的鐵縣鎮發現而命名之，為強毒株之PTV-1，在1930-1950年間造成豬的嚴重急性腦脊髓炎，導致歐洲養豬產業極大損失。1950年代之後，另一較弱毒性的病毒則在英國發現並造成Talfan disease (泰發病)。其後此弱毒株在世界廣為流行。台灣則在2000年首度發現並分離出PTV-1，之後不同型別的PTV在各地流行。本研究的目的為使用反轉錄-聚合酶鏈鎖反應(RT-PCR), 聚合酶鏈鎖反應(PCR), 巢式聚合酶鏈鎖反應(nested-PCR)結合免疫組織化學染色(IHC)及組織病理學檢查，研究PTVs感染在野外豬隻發病所扮演的角色。常見的病毒性疾病如豬瘟、假性狂犬病、日本腦炎亦使用PCR方法進行檢測。本研究蒐集了104隻淘汰之離乳豬，每隻豬隻的冷凍病材分成腦、淋巴組織、內臟組織及腸道四組進行PCR檢測。以頭數計PTVs之PCR陽性率為79.81%，而最常檢測到PTVs之部位為腸道(64.08%)及淋巴組織(45.63%)，之後為腦(25.96%)及內臟組織(23.53%)。從屏東科技大學獸醫系病理診斷中心蒐集到57隻先前診斷為非化膿性腦炎的豬隻作為回溯性樣本，並使用IHC方法進行檢測。PTV-1抗原之分布於各臟器之情形為: 腦: 5.26%；扁桃腺: 15.79%；脾臟: 31.58%；淋巴結: 26.32%；腸系膜淋巴結: 22.81%；心臟: 0%；肝臟: 28.07%；腎臟:17.54%；胃: 0%；小腸: 26.32%；大腸: 24.56%。由PCR及IHC之結果得知，最常檢測到PTVs之部位為腸道及淋巴組織。在大多數非化膿性腦炎之病灶並無發現PTV-1病毒之抗原，但PTVs之感染可能對內臟、淋巴結及腸道既有的病變有誘發加重的效果。

關鍵字

豬；豬鐵士古病毒；組織病理學；聚合酶鏈鎖反應；免疫組織化學染色

並列摘要

Porcine teschovirus (PTV) is a single-stranded, positive sense, spherical, nonenveloped RNA virus of the genus Teschovirus in the family Picornaviridae. PTVs were previously classified as Enterovirus genus, and were recently reclassified into at least 11 serotypes. Virulent PTV-1was first recognized as Teschen virus inducing polioencephalomyelitis in the Republic of Czechoslovakia in 1929. After year 1957, the lower virulent strain of PTV-1 occurred in the United Kindom called Talfan virus/disease. Nowadays, low virulent viruses spread all over the world. In Taiwan, PTV-1 was first isolated from pigs in year 2000, and the virus has since spread to most pig herds. The aim of this study was to analyze the role of PTVs infection in causing diseases in the fields by using reverse transcription polymerase chain reaction (RT-PCR) and Immunohistochemistry (IHC) combined with pathological examinations. Common swine viral infection like classical swine fever, pseudorabies, and Japanese encephalitis were also screened by PCR. Fresh frozen tissues of 104 culled postweaning pigs were collected. The tissues of each pig were pooled into four parts (groups) as brain, visceral organs, lymphoid organs, and the intestines. The positive rate of PTVs infection was 79.81% by heads, and most commonly detected in the intestines (64.08%) and lymphoid organs (45.63%), followed by the brain (25.96%) and visceral organs (23.53%). To analyze the role of PTV-1 infection in causing encephalitis, formalin-fixed paraffin-embeded (FFPE) archive tissues from 57 pigs formerly diagnosed as non-suppurative encephalitis were collected for IHC. The rates of PTV-1 antigen detection in each organ were brain: 5.26%, tonsil: 15.79%, spleen: 31.58%, lymph nodes: 26.32%, mesenteric lymph node: 22.81%, heart: 0%, liver: 28.07%, kidney: 17.54%, stomach: 0%, small intestines: 26.32%, large intestines: 24.56%. Both PCR and IHC showed that PTVs were most commonly detected in lymphoid organs and intestines. In most cases of encephalitis, there was no intralesional PTV-1 antigen detected. However, the presence of PTVs may have significance in aggravating pre-existed lesions in the visceras, lymphoid organs, and intestines, because these lesions were associated with higher PTVs detection.

並列關鍵字

Pig； Porcine teschovirus；Histopathology；Polymerase chain reaction；Immunohistochemistry

參考文獻

Lin, Y.-L., 2009a. The Molecular Epidemiology Study of Porcine Teschovirus in Taiwan. Abstract in http://vettech.nvri.gov.tw/AppendixEdit/colloquium/862.doc.

Auerbach, J., Prager, D., Neuhaus, S., Loss, U., Witte, K.H., 1994, Grouping of porcine enteroviruses by indirect immunofluorescence and description of two new serotypes. Zentralbl Veterinarmed B 41, 277-282.

Bartlett, J.M., Stirling, D., 2003, A short history of the polymerase chain reaction. Methods Mol Biol 226, 3-6.

Bodian, D., 1955, Emerging concept of poliomyelitis infection. Science 122, 105-108.

Coons, A.H., Leduc, E.H., Connolly, J.M., 1955, Studies on antibody production. I. A method for the histochemical demonstration of specific antibody and its application to a study of the hyperimmune rabbit. J Exp Med 102, 49-60.