河南部分地区不同免疫频次下猪圆环病毒2型流行病学调查

Epidemiological Investigation of Porcine Circovirus Type 2 with Different Immunization Frequencies in Some Areas of Henan Province

为了解2019-2021年河南部分地区规模化猪场中不同免疫频次下猪圆环病毒2型(PCV2)的流行情况,本试验采集河南部分地区规模化猪场血液样本1454份,分别采用酶联免疫吸附测定(ELISA)方法和聚合酶链反应(PCR)方法进行血清PCV2抗体检测和PCV2核酸检测。结果显示,2019-2021年PCV2抗体阳性率分别为77.9%、39.3%和34.7%,免疫密度分别为91.1%、48.5%和39.4%;未免疫组、免疫1次组和免疫≥2次组猪的PCV2抗体阳性率分别为15.9%、74.2%和84.8%;PCV2核酸阳性率分别为13.6%、5.0%和4.8%;未免疫组猪的PCV2抗体阳性率显著低于免疫1次组和免疫≥2次组(P<0.05);免疫1次组、免疫≥2次组猪的PCV2核酸阳性率均显著低于未免疫组(P<0.05)。结果表明,河南部分地区免疫和未免疫猪场均有PCV2感染,增加PCV2疫苗免疫频次可以提高PCV2抗体水平,降低猪感染PCV2的风险,更有利于PCV2防控。

To understand the prevalence of porcine circovirus type 2(PCV2)with different immunization frequencies in large-scale pig farms in some areas of Henan province from 2019 to 2021,this study collected 1454 blood samples from pigs.Enzyme-linked immunosorbent assay(ELISA)and polymerase chain reaction(PCR)methods were used for serum PCV2 antibody detection and PCV2 nucleic acid detection,respectively.The results showed that the PCV2 antibody positivity rates were 77.9%,39.3%,and 34.7%from 2019 to 2021,and the immunization densities were 91.1%,48.5%,and 39.4%,respectively.The PCV2 antibody positivity rates for the non-immunized group,immunized once group,and immunized≥2 times group were 15.9%,74.2%,and 84.8%,respectively.The PCV2 nucleic acid positivity rates were 13.6%,5.0%,and 4.8%,respectively.The PCV2 antibody positivity rate in the non-immunized group was significantly lower than that in the immunized once and immunized≥2 times groups(P<0.05).The PCV2 nucleic acid positivity rates in the immunized once and immunized≥2 times groups were both significantly lower than that in the non-immunized group(P<0.05).The results indicate that PCV2 infection exists in both immunized and non-immunized pig farms in some areas of Henan province.Increasing the frequency of PCV2 vaccine immunization can enhance PCV2 antibody levels,reduce the risk of pig infection with PCV2,and conducive to better PCV2 prevention and control.