Abstract: The study aimed to evaluate the infection status of Porcine circovirus type 2（PCV2） and the effectiveness of immunization in a large⁃scale pig farm in Guangdong. Fluorescence quantitative PCR（qPCR）and ELISA were used to test 140 blood samples collected from the pig farm. The results showed that after immunization at 14 days of age，the average S/P value of Cap protein antibodies in piglets reached the highest at 1.093 at 21 days of age，with the highest antibody positive rate reaching 92%. In pigs aged from 90 to 198 days，the S/P value of Cap protein antibodies decreased from 0.764 to 0.418，and the antibody positive rate decreased from 80% to 35% ， indicating a downward trend in antibody levels after 90 days of age. In pigs aged from 133 to 198 days，the positive rate of Rep protein antibodies increased from 10% to 45%，and the nucleic acid positive rate increased from 10% to 95%. Moreover，42.1%（8/19）of the positive samples had a viral load greater than 107 copies/mL，suggesting that PCV2 infection occurred in the fattening pigs of this farm. The experiment showed that PCV2 infection occurred in the pig population around 133 days of age in this farm. The results of pathogen and serological testing provide a reference for optimizing the immunization program.

Key words: Porcine Circovirus type2, Real?Time Quantitative Polymerase Chain Reaction, Enzyme?Linked Immunosorbent Assay, Cap protein antibodies, Rep protein antibodies

摘要： 为评估广东某规模化猪场猪圆环病毒2型（PCV2）感染情况及免疫效果，应用荧光 定量PCR（qPCR）和ELISA对猪场采集的140份血液样本进行检测。结果显示仔猪14日龄免疫 后，在21日龄时PCV2 Cap 蛋白抗体S/P 平均值最高可达1.093，抗体阳性率最高可达92%； 90－198日龄猪群Cap蛋白抗体S/P值由0.764下降至0.418，抗体阳性率由80%下降至35%，显 示90日龄后抗体水平呈下降趋势；133－198日龄猪群PCV2 Rep蛋白抗体阳性率由10%升高至 45%，PCV2核酸阳性率由10%升高至95%，且42.1%（8/19）阳性样品的PCV2核酸拷贝数>107 拷贝/mL，病毒载量高，提示该猪场育肥猪群PCV2发生感染。本试验检测结果表明该猪场猪 群于133日龄前后出现PCV2感染，病原学和血清学检测结果为优化免疫程序提供参考依据。

关键词: 猪2型圆环病毒, 荧光定量PCR, ELISA, Cap蛋白抗体, Rep蛋白抗体