Report on Influenza Variant in Swine in China Lacks Context

Significant attention is being paid to a study published in the Proceedings of the National Academy of Sciences this week. The study says a Eurasian avian-like H1N1 swine influenza virus with 2009 pandemic genes can facilitate human infection. Animal health experts from the U.S. Department of Agriculture (USDA), pork industry veterinarians and U.S. universities have reviewed the study published in the Proceedings of the National Academy of Sciences, and agree the study has scientific rigor. However, it does not contain important context essential for complete understanding of the present situation overseas nor the potential threat to the U.S. swine herd and consumers.

The following information helps broaden understanding of the H1N1 influenza virus in the study.

  • Eurasian avian-lineage (EA) H1N1 is not a new strain of influenza in pigs.
  • The G4 genotype, based on the whole genome constellation, has been detected since at least 2016, frequently in Chinese pigs.
  • USDA and U.S. pork industry experts encourage caution when interpreting this study.
  • Tests conducted on G4 EA H1N1 suggest this group of swine influenza viruses may pose a potential risk, however, no greater risk than other swine strains evaluated in similar tests.
  • There was no evidence in the report for human infection, illness, or human-to-human transmission.
  • Prior to release of this study, a candidate vaccine virus from a closely related EA H1N1 virus had already been contributed by the World Health Organization Collaborating Center at China CDC.
  • Since 2008, the U.S. Centers for Disease Control and Prevention (CDC) and the USDA have had a joint influenza working group to share information from pigs and people. By collaborating and sharing scientific information on influenza strains, significant efforts have been made to protect both human and swine health. The surveillance in pigs is made possible through pork producer participation and payment for the initial diagnostics.
  • It is the opinion of the experts who reviewed this paper that if this virus were in the U.S. pig population, it would be detected by the diagnostic tests available at U.S. veterinary diagnostic labs and USDA surveillance. EA H1N1 strains, including G4, have not been found in human or swine surveillance mechanisms in the USA.
  • Surveillance in animals, research, and cooperation among animal and human health experts are critical in the early identification of diseases with the potential to become global issues.
  • Appropriate preventive measures to help prevent the spread of influenza disease are essential:
  • When applicable, get vaccinated against human seasonal influenza.
  • Wash hands with soap and water frequently. If you can't, use an alcohol-based hand sanitizer with at least 60% alcohol.
  • Avoid touching your face.
  • Wear a mask when in public.
  • If you feel sick, stay home.