台灣地區鴿子及燕雀目鳥類環狀病毒流行病學研究

Epidemiological Analysis of Circovirus Isolated from Pigeon and the order Passeriformes in Taiwan

林怡君(Yi-Jiun Lin)

指導教授 ： 蔡向榮

國立臺灣大學/獸醫專業學院/獸醫學研究所/碩士(2012年)

https://doi.org/10.6342/NTU.2012.02239

摘要

鴿子環狀病毒 (Pigeon circovirus, PiCV) 為在年輕鴿群中一新浮現性之疾病，並且被認為是幼鴿症候群 (Young pigeon disease syndrome)的重要因素之一。而環狀病毒在燕雀目鳥類 (order Passeriformes) 如金絲雀及其他雀科鳥類等所扮演的角色鮮少有報告，目前在台灣燕雀目鳥類為相當常見之鳥種，但並無相關環狀病毒盛行率之報告。此篇研究主要是調查台灣地區鴿子及燕雀目鳥類環狀病毒的盛行率及其親緣性分析，PiCV檢測部分自2009-2011年共蒐集台灣北部及中部共56個鴿舍736隻賽鴿及57隻種鴿之共泄腔拭子與全台391隻野鴿之糞便拭子，鴿舍之陽性率為 94.6 % (53/56)，賽鴿及種鴿之檢測陽性率分別為 68.5 % (504/736) 及38.6 % (22/57)，且PiCV陽性率與賽鴿具臨床症狀如下痢、食慾不振、體重下降或飛行表現不佳等呈極顯著之差異(p<0.01)；而野鴿之檢測陽性率為31%，且各地區之陽性率差異不大。將部分核酸產物經定序後，與基因庫 (GenBank) 中不同國家之PiCV序列比對，ORF V1之核酸序列及胺基酸序列比對結果相似度為94.3-99.6%及87.1-100 %，而另一個ORF C1與基因庫之比對結果相似度分別為74.2-99.2 %及73.2-99.8 %，且此台灣分離株與比利時株較接近，顯示台灣地區之鴿子可能由國外引進不顯性感染PiCV之健康鴿，並造成大規模之病毒傳播。另利用原位雜交法可見病毒核酸標記在肝、腎及肺的細胞質中。而在寵物鳥店之鳥類自2010-2011年共蒐集18場310隻鳥類之糞便拭子，寵物鳥店之環狀病毒陽性率為 88.9 % (16/18)，而其環狀病毒盛行率為54.8 % (170/310)，以燕雀目鳥類之綠繡眼陽性率最高為 91.9 % (102/111)。將ORF V1之部分核酸產物經定序後，與基因庫 (GenBank) 之不同鳥種之序列比對，其核酸序列相似性百分比為61.2-100 %，依其演化的距離及相異度可區分為4個分支，分別與Psittacine beak and feather disease virus (PBFDV), PiCV, Finch circovirus (FiCV) 及 Raven circovirus (RaCV) 較接近；將與PiCV分支相近之ORF C1與和GenBank中不同國家之鴿子環狀病毒分離株核酸序列及胺基酸序列相比，可得相似性百分比為77.2-99.6 %及76.4-100 %，顯示燕雀目鳥類可被跨鳥種之環狀病毒感染的可能性。由此研究可得知，環狀病毒藉由糞便水平傳播在台灣的鴿子及常見的燕雀目鳥類之間有高的盛行率，且由核酸序列、胺基酸序列及親緣性分析可得其病毒來源相當複雜。

關鍵字

鴿子環狀病毒 ； 幼鴿症候群 ； 燕雀目鳥類 ； 多引子滾環式增幅法 ； 原位雜交法

並列摘要

Circovirus infection is an emerging viral disease of young pigeons and maybe a crucial factor of young pigeon disease syndrome. In addition, little is known about the roles of circoviruses in causing disease in passerine species such as canaries and finches. The order Passeriformes are the most common birds in Taiwan, however there has no relevant studies about the prevalence of circovirus in these species. The aims of this study were to investigate the prevalence and the genetic features of the circovirus strains that infecting the pigeon and birds of the order Passeriformes. In this study, cloacal swabs were collected from 736 racing pigeons and 57 breeder pigeons of 56 lofts in northern and central Taiwan, and also fecal swabs were collected from 391 wild pigeons in Taiwan from 2009-2011. 53 out of 56 lofts were positive and the prevalence of pigeon circovirus (PiCV) were 68.5% (504/736) and 38.6% (22/57), respectively. Racing pigeons with clinical signs such as diarrhea, anorexia, weight loss and poor race performance were related to positive percentage (p<0.01). The prevalence of PiCV in wild pigeons were 31% (121/391) with little difference in 4 areas of Taiwan. PiCVs indicated 94.3-99.6 % and 89.1-100 % of nucleotide and amino acid identity in ORF V1, and ORF C1 sequences were 74.2-99.2 % and 73.2-99.8 %, respectively. Phylogenetic analysis of capsid protein genes of the Taiwanese strains were closely related to Belgian strain, which is probably due to the fact that the PiCV-carrying healthy pigeons introduced from abroad could most likely be the origin of the virus and spread to pigeons in Taiwan. The results of in situ hybridization were found mostly in the cytoplasm of infected cells in liver, kidney and lung. Moreover, fecal swabs from 310 birds were collected in pet bird shops in Taiwan from 2010-2011, and the prevalence of circovirus in these birds were 54.8 % (170/310). The highest positive rate was Zosterops japonicas with 91.9 % (102/111). The ORF V1 sequences revealed these viruses were classified in Psittacine beak and feather disease virus (PBFDV), PiCV, Finch circovirus (FiCV) and Raven circovirus (RaCV). The ORF C1 related to PiCV compared with GenBank indicated 77.2%-99.6% and 76.4-100 % of nucleotide and amino acid identity, which showed the possibility of cross-species transmission of circoviruses among order Passeriformes. The results of this study indicated that the PiCV-positive rate was high in the pigeon and order Passeriformes populations by horizontal transmission of fecal in Taiwan, and according to the sequence diversity and phylogenetic trees indicated the complex sources from nature or others.

並列關鍵字

Pigeon circovirus ； young pigeon disease syndrome ； order Passeriformes ； multiply primed rolling-circle amplification ； in situ hybridization

參考文獻

王羣，2006。豬環狀病毒之概述。行政院農業委員會家畜衛生試驗所。

許志明，2006。APV及PBFDV的分子分析與鸚鵡APV酵素免疫分析套組之開發。國立台灣大學碩士論文，台北。

Abadie, J., Nguyen, F., Groizeleau, C., Amenna, N., Fernandez, B., Guereaud, C., Guigand, L., Robart, P., Lefebvre, B., Wyers, M., 2001, Pigeon circovirus infection: pathological observations and suggested pathogenesis. Avian Pathol 30, 149-158.

Adair, B.M., 2000, Immunopathogenesis of chicken anemia virus infection. Dev Comp Immunol 24, 247-255.

Allan, G.M., Ellis, J.A., 2000, Porcine circoviruses: a review. J Vet Diagn Invest 12, 3-14.