臺灣新近分離新城雞病病毒野外株之毒力與核酸序列分析

Pathogenicity and Nucleotide Sequence of Newcastle Disease Virus Isolated from Recent Outbreak in Taiwan

楊程堯(Cheng-Yao Yang) ； 張伯俊(Poa-Chun Chang) ； 沈瑞鴻(Jui-Hung Shien) ； 陳秋麟(Chu-Lin Chen) ； 李龍湖(Long-Huw Lee) ； 謝快樂(Happy K. Shieh)

《中華民國獸醫學會雜誌》 23卷1期 (1997/02) Pp. 34-42

https://doi.org/10.7009/JTCSVS.199702.0034

摘要

民國84年間台灣爆發新城雞病大流行，病雞在臨床上呈現精神沈鬱、厭食、雞冠發疳和歪頭扭頸的神經症狀。解剖病變上顯示心臟冠狀溝出血點、肺炎、腺胃出血、腸道淋巴組織腫大出血。本實驗室自疫區病雞中採集腦、肺與氣管、脾臟等臟器，接種於9-11日齡胚胎蛋尿囊腔和雞胚胎纖維芽母細胞中進行微生物學檢查，得到具有紅血球凝集性之病毒；經高免血清和電子顯微鏡的檢查結果，證實其為新城雞病病毒。以此方法共分離到三株野外毒株。利用1日齡無特定病源小雞，測得其腦內接種指數分別是1.65、1.675、1.675；病毒斑分析發現其直徑均大於0.3cm，以9-11日齡胚胎蛋測定其平均致死時間均於60小時，顯示此三株分離株為強毒株。核酸定序發現此台灣分離株之HN（hemagglutinin-neuraminidase）基因序列與國外發表之強毒株接近，但已有明顯差別（9-18%之核酸序列差異性），顯示此病毒已存在於本省相當時日，此一結果值得防疫單位注意。此外，耐熱性試驗發現經82°C處理20秒以上，病毒即失去血球凝集性；而經82°C處理40秒以上則病毒無法存活，因此，即使在疫區內熟食雞肉也應無感染病毒之顧慮。

關鍵字

新城病雞 ； 病毒毒力 ； 核酸定序

並列摘要

An outbreak of Newcastle disease occurred in 1995 in Taiwan. The infected chickens exhibited depresion, anorexia, cyanosed comb, torticollis and other symptoms of Newcastle disease (ND). Gross necropsies revealed lesions including ecchymotic hemorrhages of heart, pneumonia, accompanied by hemorrhages of proventriculus and Iymphatic tissue of intestine. Virus were isolated from the brain, lung, trachea and spleen of infected chickens, by inoculating the tissue homogenate into the nine-to-eleven-day embryonated chicken eggs. The viruses isolated showed hemagglutination ability and were confirmed to be Newcastle disease virus (NDV) by hyperimmune serum hemagglutination-inhibition assay and electron microscopy. Three isolates, designated as TW /95-3, TW/95-7 and TW/ 95-11 were obtained. The intracerebral pathogenicity indexes (ICPI) of three isolates were found to be 1.65, 1.675 and 1.675. The mean death time (MDT) of the three isolates were all less than 60 hours, and plaque sizes generated by the three isolates were all larger than 0.3 cm in diameter. These data indicated that the three isolates were all virulent strains of NDV. Nucleotide sequence of the hemagglutinin-neuraminidase (HN) gene showed that Taiwan isolates were closely related to virulent strains of NDV isolated in other countries. However, considerable nucleotide differences (9-18%) were observed between Taiwan isolates and foreign strains of NDV, suggesting that the NDV we isolated have existed in Taiwan for a considerable period, which was noteworthy for vaccination program against ND in Taiwan. Heating experiments showed that after treatment of NDV in 82°C for 20 seconds, the viral ability to produce hemagglutination was complete abolished; after treatment in 82°C for 40 seconds, no viable virus could be detected. These results indicated that infection of NDV could not be established by eating cooked chicken meat even in the panzootic areas.

並列關鍵字

Newcastle disease ； viral pathogenicity ； nucleotide sequence