Sunday, 13 November 2011

Porcine Circovirus - Co-existence of Multiple Strains

We have always worried about porcine circovirus and the implications for human health. The treatment of bacterial co-infections to circoviruses with antibiotics gives rise to antibiotic resistant pathogens that impact on human health.

Had the truth been told in Britain in 1999-2001, things would be very different now.

If the truth was told now, things might yet be very different in the future

Co-existence of multiple strains of porcine circovirus type 2 in the same pig from China

Shao-Lun Zhai, Sheng-Nan Chen, Zu-Zhang Wei, Jian-Wu Zhang, Lv Huang, Tao Lin, Cheng Yue, Duo-Liang Ran,Shi-Shan Yuan, Wen-Kang Wei and Jin-Xue Long
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Virology Journal 2011, 8:517 doi:10.1186/1743-422X-8-517
Published: 13 November 2011

Abstract (provisional)

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.