Department of Veterinary Pathology, College of Veterinary Medicine, Seoul National University, Seoul, Korea.
CJ Cheiljedang Center, CJ CHEILJEDANG, Seoul, Korea.
Transbound Emerg Dis. 2018 Dec;65(6):1641-1647. doi: 10.1111/tbed.12921. Epub 2018 Jun 7.
The objective of this study was to compare the severity of reproductive failure caused by either a single or a dual infection with porcine reproductive and respiratory syndrome virus (PRRSV)-1 and PRRSV-2 in late-term pregnancy gilts. Pregnant gilts were intranasally administered PRRSV-1, PRRSV-2 or both at 3 weeks before the expected farrowing date (93 days of gestation). Regardless of single and dual infection, PRRSV-infected pregnant gilts experienced premature farrowing (103-109 days of gestation) compared with negative control gilts which carried their pregnancy to full term (114-115 days of gestation). Pregnant gilts infected with only PRRSV-1 had a significantly (p < 0.05) higher number of genomic copies of PRRSV-1 in their blood compared with dually infected gilts. Additionally, stillborn foetuses and live-born piglets from pregnant gilts infected with only PRRSV-1 had a significantly (p < 0.05) higher number of PRRSV-1-positive cells per unit area of tissue sections examined, compared to pregnant gilts dually infected with PRRSV-1 and PRRSV-2. In contrast, pregnant gilts infected with only PRRSV-2 showed no difference in the number of genomic copies of PRRSV-2 compared with dually infected pregnant gilts and there were no significant differences in PRRSV-2-positive cells per unit area in tissues of stillborn foetuses and live-born piglets from pregnant gilts infected with PRRSV-2 only compared with dually infected gilts. Interestingly, even though PRRSV-2 was shown to replicate more efficiently compared with PRRSV-1 in dually infected pregnant gilts, neither PRRSV type was able to exacerbate reproductive failure in pregnant gilts already dually infected with PRRSV-1 and PRRSV-2. Our results suggest that the severity of reproductive failure is similar between dual (PRRSV-1 and PRRSV-2) and single infection (PRRSV-1 or PRRSV-2).
本研究旨在比较晚期妊娠母猪单一或双重感染猪繁殖与呼吸综合征病毒（PRRSV）-1 和 PRRSV-2 引起繁殖失败的严重程度。在预计分娩前 3 周（妊娠 93 天），通过鼻腔向怀孕母猪接种 PRRSV-1、PRRSV-2 或两者混合。与未感染的对照组母猪（妊娠 114-115 天）相比，无论单一或双重感染，感染 PRRSV 的怀孕母猪均出现早产（妊娠 103-109 天）。与双重感染的母猪相比，仅感染 PRRSV-1 的怀孕母猪血液中 PRRSV-1 的基因组拷贝数显著更高（p<0.05）。此外，仅感染 PRRSV-1 的怀孕母猪所产死胎和活产仔猪的组织切片中 PRRSV-1 阳性细胞数显著更高（p<0.05），而双重感染 PRRSV-1 和 PRRSV-2 的母猪所产死胎和活产仔猪的组织切片中 PRRSV-1 阳性细胞数没有差异。相比之下，仅感染 PRRSV-2 的怀孕母猪的 PRRSV-2 基因组拷贝数与双重感染的怀孕母猪相比没有差异，并且仅感染 PRRSV-2 的怀孕母猪所产死胎和活产仔猪的组织切片中 PRRSV-2 阳性细胞数与双重感染的母猪相比也没有差异。有趣的是，尽管双重感染的母猪中 PRRSV-2 的复制效率明显高于 PRRSV-1，但 PRRSV-1 和 PRRSV-2 双重感染的母猪中，两种病毒均不能加重繁殖失败。我们的结果表明，双重（PRRSV-1 和 PRRSV-2）和单一（PRRSV-1 或 PRRSV-2）感染引起的繁殖失败严重程度相似。
