广西PRRSV、PCV、CSF的混合感染及PRRSV分子病原学研究

The coinfection of PRRSV,PCV and CSF in pigs and molecular etiology of PRRSVs

为了弄清2007年发生于广西一些县市猪场的高致病性猪繁殖与呼吸综合征和其他疾病的混合感染情况，从广西7个县市发生高致病性猪繁殖与呼吸综合征的猪场采集病料，进行猪繁殖与呼吸综合征病毒（PRRSV）、猪圆环病毒（PCV）及猪瘟病毒（CSF）检测，并对检测的PRRSV进行分子病原学分析。结果显示，经PCR检测，86份样品中有60份为PRRSV阳性，36份为PCV阳性，2份为CSF阳性，说明发生于广西猪群的PRRSV与PCV共感染情况比较严重。通过PRRSV ORF5基因序列比较分析发现，来自广西7个县市不同猪场的PRRSV高度同源，核苷酸序列同源性为98．5％-99．8％，推导编码的氨基酸序列同源性为98．0％～100．0％；与VR2332和LV株的核苷酸序列同源性分别为88．7％-89．7％和62．2％-63．1％，氨基酸序列同源性分别为88．6％～89．6％和60．5％～61．3％，表明7个县市不同毒株的ORF5基因区域变异不大，均属美洲型。

A very virulent porcine reproductive and respiratory syndrome was occurred in pigs in swine industry of Guangxi in 2007. To investigate the coinfection of this disease,we collected clinical samples from 7 countries of Guangxi where suffering the disease, for identification porcine reproductive and respiratory syndrome viruses （PRRSV） ,porcine cireovirus（PCV） and classical swine fever（CSF） ,and for analysis the molecular etiology of PRRSV. The PCR positive in 86 clinical samples of 7 counties of Guangxi showed that 60 were PRRSV, 36 were PCV and 2 were CSF. Sequence comparison of complete ORF5 indicated that all the PRRSVs from different geographical locations were highly homologous to each other, the nucleotide homologous were 98.5 % -99.8 %, the amino acid homologous rate were 98.0 % - 100.0 %. This local isolates shared 88.7 % -89.7 % and 62.2 % -63.1% sequence homology with VR2332 and LV strain respectively, which represents 88.6 % - 89.6 % and 60.5 % - 61.3 % similarity in deduced amino acid sequences. The results showed no significant genetic diversity among PRRSV epidemic strains, and all the epidemic strains belonged to North American genotype.