Effect of modified-live porcine reproductive and respiratory syndrome virus (PRRSv) vaccine on the shedding of wild-type virus from an infected population of growing pigs
Effect of modified-live porcine reproductive and respiratory syndrome virus (PRRSv) vaccine on the shedding of wild-type virus from an infected population of growing pigs
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DOI：
10.1016/j.vaccine.2011.10.075
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发表时间：
2012-01-05
期刊：
影响因子：
5.5
通讯作者：
Dee, Scott A.
中科院分区：
文献类型：
--
作者：
Linhares, Daniel C. L.;Cano, Jean Paul;Dee, Scott A.
人们正在努力消除美国养猪业各地区的猪繁殖与呼吸综合征病毒 (PRRSv)。然而，实现这些努力的一个重要挑战是由于PRRSv的区域传播而导致养猪单位的再次感染。本研究的目的是评估 PRRS 改良活病毒疫苗 (MLV) 对商业条件下饲养的猪群中病毒脱落和 PRRSv 感染动态的影响。该研究由两个房间组成，每个房间有 1000 头猪。每个房间的 10% 的猪都接种了 PRRSv 现场分离株。房间有独立的空气空间，并采用严格的经过科学验证的生物安全协议，以避免病原体在房间之间移动。在第 8 和 36 dpi（接种后天），攻击疫苗组的所有猪都接种了 MLV 疫苗。攻击对照组的猪接种了安慰剂。在 0、8、36、70、96 和 118 dpi 时从每个房间采集血液和口腔液样本，用于使用 PCR 检测 PRRSv RNA。还使用市售的 ELISA 测试从血清样本中筛选出 PRRSv 抗体。此外，在 70、96 和 118 dpi 时从两组收集扁桃体刮擦样本。此外，每周在 0 至 118 dpi 期间收集空气样本 6 次，并使用 qPCR 检测检测 PRRSv RNA。以病毒血症和血清转化的持续时间和程度来衡量，PRRSv 感染动态没有差异。此外，通过 PCR 检测扁桃体刮取样本 PRRSv 阳性的频率没有差异。然而，与攻击对照组相比，攻击疫苗组的 PRRSv 排放量显着减少。攻击疫苗组在 36 dpi 时的 PRRSv 阳性口腔液显着减少。此外，攻毒疫苗组空气中累积的 PRRSv 排放量显着减少。 (C) 2011 Elsevier Ltd. 保留所有权利。
There are ongoing efforts to eliminate porcine reproductive and respiratory syndrome virus (PRRSv) from regions in the United States swine industry. However, an important challenge for the accomplishment of those efforts is the re-infection of pig units due to the area spread of PRRSv. The objective of this study was to evaluate the effect of PRRS modified-live virus vaccine (MLV) on viral shedding and on dynamics of PRRSv infection in pig populations raised under commercial conditions. The study composed of two rooms of 1000 pigs each. Ten percent of pigs of each room were inoculated with a field isolate of PRRSv. Rooms had separate air spaces and strict scientifically validated biosecurity protocols were adopted to avoid movement of pathogens between rooms. At 8 and 36 dpi (days post inoculation), all pigs of the challenge-vaccine group were inoculated with a MLV vaccine. Pigs of the challenge-control group were placebo-inoculated. Blood and oral fluid samples were collected from each room at 0, 8, 36, 70,96 and 118 dpi for PRRSv RNA detection using PCR. PRRSv-antibodies were also screened from blood serum samples with a commercially available ELISA test. Additionally, tonsil scraping samples were collected from both groups at 70, 96 and 118 dpi. Moreover, air samples were collected 6 times per week from 0 to 118 dpi and were tested for PRRSv RNA using qPCR assay. There was no difference in the PRRSv infection dynamics measured as duration and magnitude of viremia and seroconversion. Also, there was no difference in the frequency of tonsil scraping samples PRRSv-positive by PCR. However, the challenge-vaccine group had significantly less PRRSv shed compared to the challenge-control group. The challenge-vaccine group had significant less PRRSv-positive oral fluids at 36 dpi. Moreover, the challenge-vaccine group had significant reduction in the cumulative PRRSv shed in the air. (C) 2011 Elsevier Ltd. All rights reserved.