title: Co-existence of multiple strains of porcine circovirus type 2 in the same pig from China.
abstract: Pigs are often co-infected by different viral strains from the same virus. Up to now, there are few reports about co-existence of different porcine circovirus type 2 (PCV2) strains in China. The aim of this study was to evaluate it in Chinese swine herds. 118 PCV2 positive DNAs isolated from diseased pigs identified by classic PCR were re-detected using a modified differential PCR assay. The results indicated that co-existence rates of PCV2 were 32.2% (38/118) in diseased pigs and 0% (0/41) in asymptomatic pigs. Four PCV2 complete genomes were cloned from two co-infected samples and their nucleotide (nt) identities were 95%-97.3%. The phylogenetic analysis showed that four PCV2 strains were divided into different genotypes, PCV2a, PCV2b, PCV2d and PCV2e, respectively. In addition, co-existence were not detected in 41 serum samples from healthy pigs but PCV2 single infection (31.7%, 13/41) existed. These data revealed that the co-existence of different strains of PCV2 might contribute to the development of more severe clinical symptoms for pigs. This is the first report confirming the co-existence of different PCV2 strains in Chinese swine herds. Meanwhile, this study could help us to understand new infection and prevalence forms of PCV2 clinically.
authors.affiliation: Department of Swine Infectious Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, China.
authors.forename: Shao-Lun
authors.initials: SL
authors.lastname: Zhai
authors.forename: Sheng-Nan
authors.initials: SN
authors.lastname: Chen
authors.forename: Zu-Zhang
authors.initials: ZZ
authors.lastname: Wei
authors.forename: Jian-Wu
authors.initials: JW
authors.lastname: Zhang
authors.forename: Lv
authors.initials: L
authors.lastname: Huang
authors.forename: Tao
authors.initials: T
authors.lastname: Lin
authors.forename: Cheng
authors.initials: C
authors.lastname: Yue
authors.forename: Duo-Liang
authors.initials: DL
authors.lastname: Ran
authors.forename: Shi-Shan
authors.initials: SS
authors.lastname: Yuan
authors.forename: Wen-Kang
authors.initials: WK
authors.lastname: Wei
authors.forename: Jin-Xue
authors.initials: JX
authors.lastname: Long
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002681:China / Q000453:epidemiology; D018173:Circoviridae Infections / Q000453:epidemiology / Q000235:genetics / Q000662:veterinary* / Q000821:virology; D017925:Circovirus / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D003001:Cloning, Molecular; D060085:Coinfection; D016172:DNA Fingerprinting; D004279:DNA, Viral / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D016679:Genome, Viral; D005838:Genotype; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction / Q000379:methods; D012689:Sequence Homology, Nucleic Acid; D013552:Swine; D013553:Swine Diseases / Q000453:epidemiology / Q000235:genetics / Q000821:virology*
chemical_list: D004279:DNA, Viral
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