H5N1 highly pathogenic avian influenza clade 2.3.4.4b in wild and domestic birds: Introductions into the United States and reassortments, December 2021–April 2022

Highly pathogenic avian influenza viruses (HPAIVs) of the A/goose/Guangdong/1/1996 lineage H5 clade 2.3.4.4b continue to have a devastating effect on domestic and wild birds. Full genome sequence analyses using 1369 H5N1 HPAIVs detected in the United States (U.S.) in wild birds, commercial poultry, and backyard flocks from December 2021 to April 2022, showed three phylogenetically distinct H5N1 virus introductions in the U.S. by wild birds. Unreassorted Eurasian genotypes A1 and A2 entered the Northeast Atlantic states, whereas a genetically distinct A3 genotype was detected in Alaska. The A1 genotype spread westward via wild bird migration and reassorted with North American wild bird avian influenza viruses.…

• UD
  U.S. Department of Energy
• UD
  U.S. Department of Agriculture
• OR
  Oak Ridge Associated Universities

  Award: DE-SC0014664
• CN
  Chungbuk National University
• OR
  Oak Ridge Institute for Science and Education
• AR
  Agricultural Research Service

  Award: 6612-32000-081-00D
• AA
  Animal and Plant Health Inspection Service

  Award: 60-6040-6-005