Avian Influenza A(H5N1) Isolated from Dairy Farm Worker, Michigan

Emerg Infect Dis. 2025 Jun;31(6):1253-1256. doi: 10.3201/eid3106.250386. Epub 2025 May 2.

Abstract

Influenza A(H5N1) viruses have been detected in US dairy cow herds since 2024. We assessed the pathogenesis, transmission, and airborne release of A/Michigan/90/2024, an H5N1 isolate from a dairy farm worker in Michigan, in the ferret model. Results show this virus caused airborne transmission with moderate pathogenicity, including limited extrapulmonary spread, without lethality.

Keywords: H5N1; Influenza; Michigan; United States; clade 2.3.4.4b; ferret; highly pathogenic avian influenza; respiratory infections; zoonoses.

MeSH terms

  • Animals
  • Cattle
  • Dairying
  • Farmers*
  • Farms
  • Female
  • Ferrets
  • Humans
  • Influenza A Virus, H5N1 Subtype* / classification
  • Influenza A Virus, H5N1 Subtype* / genetics
  • Influenza A Virus, H5N1 Subtype* / isolation & purification
  • Influenza A Virus, H5N1 Subtype* / pathogenicity
  • Influenza, Human* / epidemiology
  • Influenza, Human* / transmission
  • Influenza, Human* / virology
  • Michigan / epidemiology
  • Orthomyxoviridae Infections* / transmission
  • Orthomyxoviridae Infections* / virology