云南省新发猪圆环病毒3型感染状况调查与全基因进化分析

INVESTIGATION INTO THE EPIDEMIOLOGICAL STATUS AND PHYLOGENETIC ANALYSIS OF PORCINE CIRCOVIRUS TYPE 3 IN YUNNAN PROVINCE

为了解猪圆环病毒3型(PCV3)在云南省不同地区猪群中的流行情况,针对PCV3基因保守区域设计特异性引物,优化反应条件,建立PCR快速检测方法,并采用该方法对采自云南省不同地市431份样品进行检测,将获得的部分毒株全基因序列进行遗传进化分析。结果显示:本研究成功建立了一种快速、特异和灵敏的PCV3检测方法;云南省12个地(市)29县(区)中,8个地(市)12个县(区)检测出阳性样品;431份样品中有43份PCV3阳性样品,阳性率为9.98%;获得的3株PCV3全基因组序列与参考毒株之间的核苷酸同源性为98.6%~99.5%,进化树显示3株云南毒株形成一个小的进化分支,属于PCV3a基因型。本研究结果表明,PCV3在云南省多个地区呈一定的流行趋势,流行毒株以PCV3a基因型为主,有必要进一步开展云南地区PCV3流行病学调查,并提出防控对策。

In order to understand the prevalence of Porcine circovirus virus type 3(PCV3)of pigs in different regions of Yunnan province,a rapid PCR method was developed using specifi c primers for PCV3 conservative genomic area and the reaction conditions were optimized in the present study.Total 431 serum samples collected from 29 counties(districts)in 12 districts(cities)of Yunnan province and tested using this PCR method.As a result,43 serum samples from 8 districts(cities)and 12 counties(districts)were PCR positive for PCV3.Furthermore,analysis for the whole genomic sequences was performed for 3 PCV3 isolates obtained from these positive serum samples.These 3 isolates had 98.6%-99.5%nucleotide homology with the reference strains in GenBank.The phylogenetic tree analysis showed that these 3 Yunnan isolates formed a small evolutionary branch,which belonged to the PCV3a genotype.These results indicated that PCV3 infection existed in many regions of Yunnan province and PCV3a was the prevalent genotype.Therefore,it was necessary to further carry out epidemiological investigation of PCV3 in Yunnan province and put forward prevention and control countermeasures.