State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150069, China.
Vet Microbiol. 2024 Nov;298:110274. doi: 10.1016/j.vetmic.2024.110274. Epub 2024 Oct 9.
Porcine parvovirus type 1 (PPV1) can lead to reproductive disorders in pregnant sows, including stillbirth, mummification, embryonic death, and infertility (SMEDI syndrome). In this study, we isolated and identified 10 PPV1 strains in northern China, with genomes around 5 kb long and minor deletions in the 127-nt repeat region. The sequence analysis results showed that compared with strain NADL-2 (Reference strain), eight amino acid substitutions on the NS1 protein and fourteen amino acid substitutions on the VP2 protein were found in the ten isolates. Because the JX strain exhibited reduced neutralizing activity induced by commercially available vaccines in vitro, it was selected for challenge experiments in sows at 35 days of gestation. Mutant strain JX not only caused viremia, but also mild edema and mild inflammation in the trachea, lungs, lymph nodes, reproductive organs, and some intestines of the pregnant sows. Strain JX also caused fetal congestion and organ infection after penetrating the placental barrier. In conclusion, this study focused on the variation and evolution of PPV1 in northern China, screened a strain with reduced neutralizing activity, and determined that it has a certain degree of pathogenicity.
猪细小病毒 1 型（PPV1）可导致妊娠母猪发生繁殖障碍，包括死胎、木乃伊胎、胚胎死亡和不孕（SMEDI 综合征）。本研究在我国北方地区分离鉴定了 10 株 PPV1，基因组约 5kb 长，在 127nt 重复区存在小的缺失。序列分析结果表明，与 NADL-2 株（参考株）相比，10 个分离株的 NS1 蛋白有 8 个氨基酸替换，VP2 蛋白有 14 个氨基酸替换。由于 JX 株在体外对市售疫苗诱导的中和活性降低，因此选择其在妊娠 35 天的母猪中进行攻毒实验。突变株 JX 不仅引起了病毒血症，还引起了妊娠母猪气管、肺、淋巴结、生殖器官和部分肠道的轻度水肿和轻度炎症。该菌株穿透胎盘屏障后还引起了胎儿充血和器官感染。综上所述，本研究关注了我国北方地区 PPV1 的变异和进化，筛选出一株中和活性降低的病毒株，并确定其具有一定的致病性。
