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

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