猪伪狂犬病病毒HNX株在免疫猪群中水平传播能力的研究

The horizontal transmission of porcine pseudorabies virus HNX strain in vaccinated pigs

为研究猪伪狂犬病病毒(PRV)HNX株水平传播的能力及PRV活疫苗的保护效力,本研究通过以颈部肌肉接种PRV HNX株(2 m L 107 TCID50)的未免疫猪作为病毒的传染源,同居感染未免疫猪和Bartha-K61株活疫苗免疫猪,通过检测抗PRV的g B和g E蛋白抗体、中和抗体及干扰素水平等评估疫苗保护力,并利用荧光定量PCR方法检测同居感染猪排毒情况。结果显示Bartha-K61株活疫苗能够快速诱导免疫猪产生抗g B蛋白的抗体,但疫苗诱导产生的交叉保护中和抗体水平较低。同居感染期间,免疫猪和未免疫猪均出现典型的临床症状,体温明显升高。荧光定量PCR方法结果显示,疫苗免疫能够减少免疫猪排毒,但不能阻止排毒,也不能阻止野毒感染。本研究结果表明Bartha-K61株活疫苗阻止PRV HNX株水平传播的效力是有限的,有必要更换疫苗病毒株。同居感染期间,每组感染猪均表现敏感,表明PRV HNX株病毒具有较强的水平传播能力。

To evaluate the horizontal transmission of pseudorabies virus （PRV） HNX strain and the protection of Bartha-K61 live vaccine against HNX strain, pigs were inoculated intramuscularly with 107 TCID50 PRV HNX strain to cohabit with others non-immunized and vaccinated pigs for virus horizontal transmission, and evaluated the Bartha-K61 live vaccine by detections of gB antibody, gE antibody, neutralizing antibody and interferon. The result showed that all the non-immunized and vaccinated pigs developed typical clinical signs after coinhabition with the virus inoculated pigs. In addition, the seroconversion of gB antibody against vaccine Bartha-K61 developed rapidly, but the ability of neutralizing PRV HNX strain was not effecient. The virus shedding in the nasal discharges indicated that the vaccine was able to reduce virus shedding after infection. However, the vaccine was unable to prevent immunized pigs from PRV infection and virus shedding. This suggests that the capacity of the vaccine to prevent PRV HNX strain transmission is limited, and it is essential to develop new vaccine strain.