{
  "id": 8141879,
  "title": "Host type governs influenza evolutionary strategy across reservoir and spillover hosts",
  "url": "https://urgent.news/2026/09/17/host-type-governs-influenza-evolutionary-strategy-across-reservoir",
  "topic": "science",
  "section": "Science",
  "published": "2026-09-17T00:00:00.000Z",
  "source": {
    "name": "bioRxiv",
    "slug": "biorxiv",
    "url": "https://www.biorxiv.org/content/10.64898/2026.09.15.751820v1?rss=1"
  },
  "original_language": "en",
  "account": "Influenza viruses exhibit distinct evolutionary strategies depending on their host, according to a study analyzing 13,295 H3Nx sequences. H3Nx viruses are known for their ability to switch between hosts, including avian, human, swine, equine, and canine species. The research, published in the journal Nature Communications, found that while influenza viruses in mammals adapt through changes in the hemagglutinin (HA) and neuraminidase (NA) genes, those in birds show minimal selection pressure.\n\nBirds demonstrate a high rate of reassortment, where genetic material from different strains is exchanged, creating novel reassortant viruses. These reassortant lineages are often short-lived, with 29.8-47.4% of avian reassortants disappearing within the first year of circulation. Moreover, reassortment in birds does not confer any fitness advantage.\n\nConversely, reassortment in swine viruses appears to be beneficial, as reassortant lineages tend to persist longer. This suggests that reassortment may provide a survival benefit in swine. Additionally, the study revealed that reassortment patterns differ between avian and mammalian viruses. In birds, the neuraminidase (NA) gene reassorted more frequently than in swine viruses, while in swine, reassortment in the HA gene was more common than expected.\n\nThe findings suggest that host differences drive distinct evolutionary outcomes for influenza viruses. In their avian reservoirs, reassortment dominates the evolutionary process, while upon establishment in mammals, the viruses undergo varying degrees of adaptation, depending on the specific host. This research provides valuable insights into the evolutionary dynamics of influenza viruses and could inform strategies for controlling the spread and impact of these pathogens.",
  "summary": "Despite its high propensity for host switching, the evolutionary mechanisms underlying influenza host adaptation remain unclear. H3Nx influenza viruses are uniquely generalist, with long-term lineages that circulate in avian, human, swine, equine, and canine hosts. Using 13,295 H3Nx sequences, we quantified host-specific adaptive evolution and developed a pipeline to map reassortment events onto…",
  "key_points": [],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}