Ciacci Zanella Giovana, Markin Alexey, Neveau Thomas Megan, Snyder Celeste A, Souza Carine K, Arruda Bailey, Anderson Tavis K, Baker Amy L
Virus and Prion Research Unit, National Animal Disease Center, United States Department of Agriculture, Agricultural Research Service, Ames, Iowa, USA.
Department of Veterinary Microbiology and Preventive Medicine, College of Veterinary Medicine, Iowa State University, Ames, Iowa, USA.
Influenza Other Respir Viruses. 2025 Jul;19(7):e70128. doi: 10.1111/irv.70128.
The H1N1 pandemic (H1N1pdm09) lineage of influenza A viruses (IAV) emerged in North America in 2009. It spread rapidly due to efficient transmission and the limited immunity in humans, replacing the previous human seasonal H1. Human-to-swine transmission of H1N1pdm09 IAV has since contributed to genetic diversity in pigs. While most were not sustained, approximately 160 spillovers persisted in pigs in the United States for at least 1 year and reassorted with other endemic swine IAVs in most cases.
We sought to identify how transmission and reassortment with endemic IAV in swine impact virus traits and zoonotic risk in this study. We conducted a swine pathogenesis and transmission study using four swine H1N1pdm09 viruses derived from different human influenza seasons that had acquired different gene segment combinations after spillovers into swine. To assess antigenic evolution, we compared the selected swine H1N1pdm09 strains against each other and to five human seasonal H1 vaccine strains.
Ongoing circulation and reassortment resulted in viruses with variable virulence, shedding, and transmission kinetics. The H1N1pdm09 viruses retained antigenic similarities with the human vaccine strain of the same season of incursion but showed increasing antigenic distances with human seasonal H1N1 vaccine strains from other seasons.
Human seasonal H1N1 viruses are capable of replicating and transmitting in swine, and there is potential for these human-to-swine spillovers to reassort with endemic swine IAV. Controlling IAV at the human-swine interface has the benefit of reducing IAV burden in swine and subsequent zoonotic risk.
甲型流感病毒（IAV）的H1N1大流行毒株（H1N1pdm09）于2009年在北美出现。由于其高效传播以及人类免疫力有限，该毒株迅速传播，取代了之前的人类季节性H1毒株。自那时起，H1N1pdm09 IAV的人传猪现象增加了猪群中的遗传多样性。虽然大多数传播未持续下去，但在美国约有160次病毒溢出在猪群中持续了至少1年，并且在大多数情况下与其他地方性猪IAV发生了重配。
在本研究中，我们试图确定与猪群中地方性IAV的传播和重配如何影响病毒特性和人畜共患病风险。我们使用了四种源自不同人类流感季节的猪H1N1pdm09病毒进行猪发病机制和传播研究，这些病毒在溢出到猪群后获得了不同的基因片段组合。为了评估抗原进化，我们将选定的猪H1N1pdm09毒株相互比较，并与五种人类季节性H1疫苗毒株进行比较。
持续的循环和重配导致病毒具有不同的毒力、排毒和传播动力学。H1N1pdm09病毒与入侵同一季节的人类疫苗毒株保持抗原相似性，但与其他季节的人类季节性H1N1疫苗毒株的抗原距离越来越大。
人类季节性H1N1病毒能够在猪体内复制和传播，这些人传猪的溢出事件有可能与地方性猪IAV发生重配。在人猪界面控制IAV有助于减轻猪群中的IAV负担以及后续的人畜共患病风险。
