Epidemiological Analysis of Circovirus Isolated from Pigeon and the order Passeriformes in Taiwan
Date Issued
2012
Date
2012
Author(s)
Lin, Yi-Jiun
Abstract
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.
Subjects
Pigeon circovirus
young pigeon disease syndrome
order Passeriformes
multiply primed rolling-circle amplification
in situ hybridization
SDGs
Type
thesis
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