College of Veterinary Medicine, University of Minnesota, Saint Paul, United States.
Zoetis, Parsippany, United States.
Elife. 2022 Sep 2;11:e78618. doi: 10.7554/eLife.78618.
Although vaccination is broadly used in North American swine breeding herds, managing swine influenza is challenging primarily due to the continuous evolution of influenza A virus (IAV) and the ability of the virus to transmit among vaccinated pigs. Studies that have simultaneously assessed the impact of vaccination on the emergence of IAV reassortment and genetic variation in pigs are limited. Here, we directly sequenced 28 bronchoalveolar lavage fluid (BALF) samples collected from vaccinated and unvaccinated pigs co-infected with H1N1 and H3N2 IAV strains, and characterized 202 individual viral plaques recovered from 13 BALF samples. We identified 54 reassortant viruses that were grouped in 17 single and 16 mixed genotypes. Notably, we found that prime-boost vaccinated pigs had less reassortant viruses than nonvaccinated pigs, likely due to a reduction in the number of days pigs were co-infected with both challenge viruses. However, direct sequencing from BALF samples revealed limited impact of vaccination on viral variant frequency, evolutionary rates, and nucleotide diversity in any IAV coding regions. Overall, our results highlight the value of IAV vaccination not only at limiting virus replication in pigs but also at protecting public health by restricting the generation of novel reassortants with zoonotic and/or pandemic potential.
尽管疫苗接种在北美养猪场被广泛应用，但由于流感病毒 A（IAV）的持续进化以及病毒在接种猪之间传播的能力，管理猪流感仍然具有挑战性。同时评估疫苗接种对 IAV 重配和猪遗传变异的影响的研究有限。在这里，我们直接对 28 份来自接种和未接种 H1N1 和 H3N2 IAV 株共感染猪的支气管肺泡灌洗液（BALF）样本进行了测序，并对 13 份 BALF 样本中回收的 202 个单独病毒斑进行了特征描述。我们鉴定了 54 种重组病毒，它们分为 17 种单重组病毒和 16 种混合重组病毒。值得注意的是，我们发现，与未接种疫苗的猪相比，初免-加强免疫接种的猪的重组病毒较少，这可能是由于猪同时感染两种挑战病毒的天数减少所致。然而，BALF 样本的直接测序结果表明，疫苗接种对任何 IAV 编码区域的病毒变异频率、进化率和核苷酸多样性的影响有限。总的来说，我们的研究结果强调了 IAV 疫苗接种的重要性，它不仅可以限制猪体内病毒的复制，还可以通过限制具有人畜共患和/或大流行潜力的新型重组病毒的产生来保护公共卫生。
