Highlights in the History of Avian Influenza (Bird Flu) Timeline – 2020-2022


The below timeline gives a summary of significant HPAI and LPAI outbreaks in birds, infections in people, and events from 2020-2022.

  • Timelineicon
    silhouette of duck and genetic lineage with text H5N1, N1 - Wild bird adapted, Reassortment of H5N8 occurs in wild birds, leading to H5N1 with an N1 that is wild bird adapted
    • In March 2020, outbreaks of LPAI H7N3 and an outbreak of HPAI H7N3 occurred on US turkey farms.48
    • During 2020, reassortment (gene-swapping) between poultry and wild bird viruses led to the emergence of HPAI H5N1 with the NA viruses with an N1 NA from wild birds.
    • These wild bird-adapted HPAI H5N1 viruses were first identified in Europe during the fall of 2020 and spread across Europe and into Africa, the Middle East and Asia24.
    • In October-November 2020, HPAI H5N8 virus was detected in several swans, seals, and a fox in the United Kingdom64.
  • Timelineicon
    seal on beach
    • In March 2021, there were reports of HPAI H5N8 virus in seals in the United Kingdom, Germany58, and Denmark. Several subtypes of avian influenza viruses (H7N761, 63, H4N562, H4N660, H3N360 and H10N759) have caused epidemics in seals.
    • In May 2021, HPAI H5N1 virus was detected in wild fox kits51 at a rehabilitation center in the Netherlands, during an outbreak of HPAI in wild birds.
    • First human infection with avian influenza virus H10N3 reported in China in June 202149, 50.
    • In December 2021, detections of HPAI H5N1 virus were also reported in wild foxes in Estonia54.
  • Timelineicon
    brown chickens inside a chicken coup
    January-April 2022
    • From late 2021 to 2022, the predominant HPAI H5 virus causing poultry outbreaks worldwide was the wild-bird adapted HPAI H5N1virus, according to WHOA (formally known as OIE [610 KB, 6 pages]).
    • In January 2022, the first HPAI H5N1 virus (clade infection in wild birds in the United States since 2016 was reported by USDA/APHIS. Additional detections in wild birds were subsequently reported, visit the Current Situation Summary page for more information.
    • In February 2022, USDA/APHIS announced an HPAI H5N1 outbreak in turkeys in a commercial poultry facility, marking the first HPAI detection in commercial poultry in the United States since 2020.
    • In April 2022, the first human case of HPAI H5N1 virus was reported in the United States, though this detection may have been the result of contamination of the nasal passages with the virus rather than actual systemic infection.
    • Also in April 2022, the first human infection with H3N8 virus was reported in China.
  • Timelineicon
    three fox kits cuddled together
    May-August 2022
    • During 2022, detections of HPAI H5N1 virus in various mammals in the United States and other countries began.
    • In May 2022, sporadic HPAI H5 virus infections in mammals were first reported in several U.S. states and Canadian provinces as well as in other countries.
    • H5 bird flu viruses have previously been known to occasionally infect mammals that eat (presumably infected) birds or poultry including, but not limited to, the following: wild or feral animals such as foxes and seals; stray or domestic animals such as cats and dogs; and zoo animals such as tigers52and leopards53.
    • At least eight U.S. states have detected HPAI H5 virus in fox kits. Two bobcats in Wisconsin, a coyote pup in Michigan, raccoons in Washington and Michigan, skunks in Idaho and Canada, and Mink in Canada also tested positive for H5 virus.
    • Other animals that have tested positive for HPAI H5 virus include foxes55, otters55, a lynx55, a polecat55 and a badger in Europe and raccoon dogs and foxes in Japan56.
    • In June-July 2022, HPAI H5N1 virus was also detected in ten seals in Maine.