International Degree Program of Animal Vaccine Technology, International College, National Pingtung University of Science and Technology, No.1, Shuefu Road, Neipu, Pingtung 91201, Taiwan.
Research Centre for Animal Biologics, National Pingtung University of Science and Technology, No. 1 Shuefu Road, Neipu, Pingtung 91201, Taiwan.
Viruses. 2022 Mar 7;14(3):551. doi: 10.3390/v14030551.
The feedback strategy, or controlled exposure of pig herd to the porcine epidemic diarrhea virus (PEDV), significantly decreased losses during a severe outbreak in late 2013 in Taiwan. However, some pig farms still suffered from recurrent outbreaks. To evaluate the association between antibody titers and clinical manifestations, sera and colostra were analyzed from one pig farm that employed the feedback strategy. Furthermore, spike (S) gene full sequences from six positive samples of two farms with and without using feedback were compared to investigate the evolution of PEDV variants circulating in pig herds. The results in this study showed that high PEDV antibody titers do not correlate with the high rate of protection from PEDV infection. In addition, repeated feedback generated the emergence of PEDV variants with unique substitutions of N537S and Y561H in the COE domain and S769F in the SS6 epitopes. These mutations indicated the pathogenetic evolution of PEDV strains existing in the cycle of the feedback method. A very strict biosecurity practice to block the routes of pathogen transfer should be followed to achieve successful control of PEDV infections in pig herds.
反馈策略，或猪群接触猪流行性腹泻病毒（PEDV）的受控暴露，在 2013 年底台湾严重爆发期间显著降低了损失。然而，一些养猪场仍遭受反复爆发。为了评估抗体滴度与临床表现之间的关联，对采用反馈策略的一个养猪场的血清和初乳进行了分析。此外，对来自两个使用和不使用反馈的农场的六个阳性样本的 Spike（S）基因全长序列进行了比较，以调查猪群中循环的 PEDV 变异株的演变。本研究结果表明，高 PEDV 抗体滴度与 PEDV 感染的高保护率无关。此外，反复的反馈导致 COE 结构域中 N537S 和 Y561H 的独特取代以及 SS6 表位中的 S769F 的 PEDV 变异株的出现。这些突变表明在反馈方法循环中存在的 PEDV 株的致病进化。为了成功控制猪群中的 PEDV 感染，应遵循非常严格的生物安全实践以阻断病原体传播途径。
