浙江金华地区猪繁殖与呼吸综合征疫苗免疫程序的筛选及推广应用

Screening and application of immune schedule of porcine reproductive and respiratory syndrome vaccine in Jinhua area of Zhejiang Province, China

目的筛选现阶段浙江金华地区猪场常用的3种猪繁殖与呼吸综合征疫苗[高致病性蓝耳弱毒活疫苗(JXA1-R株)、弱毒活疫苗(CH-1R株)和灭活疫苗(NVDC-JXA1株)]的免疫程序,并进行推广应用。方法采集免疫了3种疫苗的38个不同规模猪场猪血清,ELISA法检测蓝耳抗体水平,记录主要的免疫程序(包括猪瘟、蓝耳和口蹄疫)。按筛选出的不同规模猪场适合的蓝耳疫苗免疫程序,选择6家应用不同猪蓝耳病疫苗的猪场进行效果验证与示范,根据这些猪场的养殖规模及免疫情况,进行疫苗或免疫程序的调整,免疫后28 d采血,分离血清,检测蓝耳抗体水平。结果蓝耳、猪瘟和口蹄疫的免疫程序较普遍,并能获得较高的蓝耳抗体水平和抗体合格率,蓝耳疫苗免疫时间一般为15或21日龄。其中高致病性毒株JXA1-R在金华地区的不同规模猪场使用最为广泛,特别是小规模和大规模猪场分别占61%和55%,临床应用以猪瘟-口蹄疫-蓝耳和蓝耳-猪瘟-口蹄疫两种免疫程序为主,且免疫时间分别为65日龄和14日龄,猪群可获得最高的蓝耳抗体水平和抗体合格率。蓝耳活疫苗(CH-1R株)在小、中、大规模猪场的使用率分别达15%、10%和18%,免疫程序为蓝耳、猪瘟和口蹄疫,且21日龄免疫蓝耳疫苗猪群可获得更高的蓝耳抗体水平和抗体合格率。猪蓝耳灭活疫苗(NVDC-JXA1株)也以蓝耳、猪瘟和口蹄疫免疫程序为主,其在小、中、大规模猪场的使用率分别达2%、10%和0%,且在15日龄免疫比在21日龄免疫可获得更高的蓝耳抗体水平。验证效果显示,6家猪场的抗体水平整体均有所提高,抗体效价至少提高12%,抗体合格率平均提高15%。结论大规模猪场采用蓝耳-猪瘟-口蹄疫免疫程序可获得更高的蓝耳抗体水平,中等规模猪场采用蓝耳-猪瘟-口蹄疫,而小规模猪场采用猪瘟-口蹄疫-蓝耳免疫程序可达到更好的免疫效果。

Objective To screen and popularize the immune schedules of three kinds of porcine reproductive and respiratory syndrome（PRRS） vaccines, i. e. live vaccine prepared with JXA1-R strain, attenuated live vaccine prepared with CH-1R strain and inactivated vaccine prepared with NVDC-JXA1 strain, available in Jinhua area of Zhejiang Province, China. Methods Porcine serum samples immunized with three kinds of PRRS vaccines were collected from 38 pig farms in different scales, and determined for antibody levels against PRRS by ELISA. The main immune schedules of above-mentioned vaccines combined with classical swine fever（CSF） and foot and mouth disease（FMD） vaccines were recorded. The screened immune schedules were verified for efficacy in six pig farms using different PRRS vaccines, based on which the vaccines or schedules were further optimized. Serum samples were collected 28 d after immunization and determined for PRRS antibody level. Results The immune schedule of PRRS-CSF-FMD was popular, by which high PRRS antibody levels and antibody qualification rate were obtained. In the schedule, PRRS vaccine was generally inoculated at age of 15 or 21 d. Highly pathogenic JXA1-R strain was widely used pig farms in different scales in Jinhua area, especially in small- and large-scale pig farms, which accounted for 61% and 55% respectively. However, two immune schedules, CSF-FMD-PRRS and PRRS-CSF-FMD, were popular in clinic, by which PRRS vaccines were inoculated at ages of 65 and 14 d respectively, and the highest level and qualification rate of PRRS antibody were obtained. The application rates of live PRRS vaccine（CH-1R strain） in small-, medium- and large-scale pig farms were 15%, 10% and 18% respectively, of which the immune schedules were PRRS-CSF-FMD, and higher level and qualification rate of PRRS antibody were obtained when the vaccine was inoculated at age of 21 d. Inactivated PRRS vaccine（NVDC-JXA1 strain）were mainly inoculated by a schedule of PRRS- CSF-FMD, of which the application rates in small-, medium- and large scale pig farms were 2%, 10% and 0% respectively, and the PRRS antibody levels of pigs inoculated at age of 15 d were higher than those at 21 d. The verification result showed that all the antibody levels in six pig farms increased, which the antibody titer increased by 12% at least, and the antibody qualification rate increased by 15% in average. Conclusion Higher PRRS antibody level was induced by a schedule of PRRS-CSF-FMD in large-scale pig farms, while better immune effects were obtained by a schedule of PRRS-CSF-FMD in medium-scale, and by CSF-FMD-PRRS in small-scale ones.