新疆6个地区规模化猪场猪圆环病毒3型感染调查和基因分析

Investigation of PCV3 Infection and Gene Analysis in Large Scale Pig Farms in Six Cities of Xinjiang

用PCR/RT-PCR方法对新疆6个地区449份猪全血或组织样品进行病毒核酸检测,在PCV3检测为阳性的样品中选取2株克隆测序验证并分析其基因序列。结果各地区均检测到PCV3,阳性率为8.1%~16.0%,平均阳性率为14.5%(65/449),其中PCV3单独感染率为33.8%(22/65);PCV3+PRRSV感染、PCV3+PCV2的感染率较高,分别为16.9%(11/65)和15.4%(10/65);PCV3+PCV2+PRRSV感染率为15.4%(10/65);PCV3与PCV2、PRV和PRRSV的四重感染率为1.5%(1/65);对日龄记录完整的石河子地区不同生长阶段猪群感染PCV3的情况进行分析,发现平均阳性率为16.0%(26/163),其中保育猪的阳性率为30.0%(12/40);所选的2株PCV3核苷酸序列同源性为100%,与国内外参考毒株的同源性为97.9%~100.0%;遗传进化分析表明基因序列属于3a亚群。表明PCV3在新疆6地市规模化养猪场中以单独感染或与其他病原混合感染情况普遍存在,不同生长阶段猪群均有感染PCV3。

This test used PCR/RT-PCR to detect and analyze 449 whole blood or tissue samples in large scale pig farms in 6 regions of Xinjiang,two samples that tested positive for PCV3 were selected for cloning and sequencing verification,and their gene sequences were analyzed.The results showed that PCV3 was detected in all regions,the positive rate was 8.1%-16.0%,and the average total positive rate was 14.5%(65/449).The analysis of gene detection results of PCV3 and other pathogens showed that the infection rate of PCV3 alone was 33.8%(22/65);The infection rates of PCV3+PRRSV and PCV3+PCV2 were 16.9%(11/65)and 15.4%(10/65),PCV3+PCV2+PRRSV was the main co-infection,and the infection rate was 15.4%(10/65).The quadruple infection rate of PCV3,PCV2,PRV and PRRSV was the lowest,with 1.5%(1/65);The infection rate of PCV3 in pigs of different growth stages in Shihezi area was analyzed,the average positive rate of PCV3 infection was 16.0%(26/163),and the positive rate of nursery pigs was the highest,30.0%(12/40);According to the homology analysis,the nucleotide sequence homology of the two selected PCV3 strains was 100%,compared with the reference strains at home and abroad,the homology was 97.9%-100.0%;Genetic evolution analysis showed that the gene sequence obtained from the experiment belonged to 3a subgroup.The results showed that PCV3 infection was common in large-scale pig farms in six cities of Xinjiang,either alone or mixed with other pathogens,PCV3 infection was found in pigs at different growth stages,the higher positive rate of nursery pigs may be caused by the decrease of maternal antibody level,the nucleotide sequences of the two PCV3 strains were highly homologous,which was close to the reference sequence of PCV3a subtype.