广西北部湾地区猪圆环病毒2型检测及其ORF2遗传变异分析

DETECTION AND GENETIC VARIATION ANALYSIS OF ORF2 GENE OF PORCINE CIRCOVIRUS TYPE 2 IN GUANGXI BEIBU GULF REGION

为了解猪圆环病毒2型(Porcine circovirus type 2,PCV2)在广西北部湾地区的流行情况和其ORF2基因的遗传变异规律,本研究采用PCR方法对2016年采自广西北部湾地区规模猪场和农村散养户的306份疑似PCV2感染猪的血液和组织样品进行了PCV2的病原学检测,同时对分离的4株PCV2 ORF2基因进行PCR扩增、克隆和测序,并与Gen Bank中登录的34株国内外PCV2参考株ORF2序列进行比对和遗传进化分析。结果表明:PCV2检测阳性样品为129份,阳性率为42.16%。随机选取的4份阳性病料PCV2 ORF2基因测序结果显示,4个毒株遗传关系上均属于Group 1(PCV2b),其中BBW-1和BBW-2分离株属于1A分支且分别与Fd3株(AY321984)和NL_PMWS_3株(AY484415)同源性较高,BBW-3和BBW-4分离株属于1B分支且BBW-4分离株与Hu Zhou0301株(AY536756)和NL_Control_1株(AY484407)同源性较高,其ORF2基因核苷酸和氨基酸同源性分别为98.9%~99.5%和93.9%~95.4%,说明该地区PCV2的优势基因型是PCV2b。研究结果不仅有利于掌握广西北部湾地区PCV2流行毒株同源性情况,而且将为该地区(porcine circovirus associated disease,PCVAD)的防治和新型疫苗的研制提供依据。

To investigate the prevalence of Porcine circovirus type 2(PCV2)and the genetic variation in viral structural protein in Guangxi Beibu Gulf region,a total of 306 blood and tissue samples of suspect PCV2-infected pigs were collected from large-scale pig farms or rural households in this region in 2016 and tested using PCR method.As a result,129 samples(42.16%)from these herds were PCV2 positive.Four PCV2 strains were isolated and their ORF2 genes were sequenced and compared with 34 reference strains in the GenBank.The results indicated that these four PCV2 strains belonged to Group 1(PCV2b)and sequence identities were 98.9%-99.5%for nucleotide sequences and 93.9%-95.4%for amino acid sequences,respectively.The BBW-1 and BBW-2 strains were classified in subgroup 1A along with the reference strain Fd3/France(AY321984)and NL_PMWS_3/Netherlands(AY484415)while BBW-3 and BBW-4 were in subgroup 1B and BBW-4 with the reference strains HuZhou0301/China(AY536756)and NL_Control_1/Netherlands(AY484407).These data indicated that PCV2b was still the dominant genotype of PCV2 in Guangxi Beibu Gulf region.These results would be beneficial to understanding the prevalence of PCV2 in this area and prevention of Porcine circovirus associated disease.