江苏常州地区PRRSV、PCV2、PCV3的流行特征及混合感染分析OA

To assess the epidemiological characteristics of porcine reproductive and respiratory syndrome virus(PRRSV),porcine circovirus type 2(PCV2),and porcine circovirus type 3(PCV3)in Changzhou,Jiangsu province,this study collected 237 porcine serum samples and corresponding swab samples from the region in 2025.Commercial kits were used to detect antibodies and pathogens.For pathogen-positive samples,target genes were amplified,sequenced,and subjected to phylogenetic analysis.The re-sults showed that the PRRSV antibody positive rate was 29.11%,with a farm-level positive rate of 16.67%;the pathogen positive rate was 15.61%,with a farm-level posi-tive rate of 25.00%.All eight obtained gene sequences belonged to PRRSV-2 lineage 1,sharing the highest homology with NADC30.For PCV2,the antibody positive rate was 73.84%,with a farm-level positive rate of 83.33%;the pathogen posi-tive rate was 86.92%,with a farm-level positive rate of 100.00%.All seven ORF2 gene sequences belonged to the PCV2d subtype.For PCV3,the antibody positive rate was 24.05%,with a farm-level positive rate of 66.67%;the pathogen posi-tive rate was 56.12%,with a farm-level positive rate of 91.67%.All ten ORF2 gene sequences belonged to the PCV3a sub-type.Analysis of mixed infections revealed that co-infection of PCV2 and PCV3 was predominant,with a positive rate of 53.16%and a farm-level positive rate of 91.67%;the positive rate for PRRSV and PCV2 co-infection was 12.24%,with a farm-level positive rate of 25.00%;the positive rates for PRRSV and PCV3 co-infection and triple infection were both 8.44%,with farm-level positive rates of 16.67%for both.This study indicates that PRRSV in Changzhou exhibits a sporad-ic,low-prevalence pattern with a single virus strain type.Most non-vaccinated farms have achieved stable control,establis-hing a foundation for regional eradication.PCV2 and PCV3 are highly prevalent,with widespread co-infections.Current PCV2 vaccines struggle to block the transmission of field virus strains,suggesting the need for optimized prevention and control strategies.This research provides a scientific basis for transitioning regional animal disease prevention and control strategies from immunoprophylaxis to precision prevention,control,and eradication.