#18,498
The ECDC publishes a highly detailed avian influenza surveillance report roughly every 3 months, and while they tend to be EU centric, in its 60+ pages you'll find ample coverage of outbreaks and infections from around the world.
The graphic above illustrates that by 2019 the the number of reported H5 human infections had dwindled to near zero, but have increased significantly each year since. In 2024, the focus of H5 spillovers into humans shifted largely over to the United States.Four years ago, following a complex series of genetic changes to the HPAI H5 virus, we began to see a global surge and spread of H5N1, characterized by increased spillovers into mammals (mink, foxes, marine mammals, and eventually even cattle).
These quarterly reports make excellent reference material, well worth perusing. I've posted the ECDC summary and link below.
Avian influenza overview September-December 2024
Surveillance and monitoring
18 Dec 2024
Publication series: Avian influenza overview
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Between 21 September and 11 December 2024, 45 cases of zoonotic avian influenza infection with A(H5N1) clade 2.3.4.4b virus were reported from North America. These infections were mainly linked to exposure to infected animals through occupational activities. Human infections with avian influenza viruses remain rare and sporadic, without evidence of sustained human-to-human transmission so far.
Many HPAI outbreaks in domestic birds were clustered in areas with high poultry density and characterised by secondary farm-to-farm spread. Waterfowl, particularly the mute swan, were primarily affected during this reporting period, with HPAI virus detections focused on south-eastern Europe. Notably, A(H5N5) viruses expanded their geographic and host range, resulting in a surge in detections and mortality events described in gulls and crows.
No new HPAI virus detections in mammals were reported in Europe during this reporting period, but the number of dairy cattle farms reportedly affected in the United States of America (USA) rose to > 800 in 16 States, and HPAI virus was identified in two pigs in a mixed-species farm. Between 21 September and 11 December 2024, 56 new human cases with avian influenza virus infection were reported from North America (45 A(H5N1) cases), Viet Nam (one A(H5)) and China (ten A(H9N2) cases). Most of the A(H5) human cases in North America (95.6%, n = 43/45) had reported exposure to poultry, live poultry markets, or dairy cattle prior to avian influenza virus detection or onset of illness.
Human infections with avian influenza viruses remain rare and no evidence of human-to-human transmission has been documented in the reporting period. The risk of infection with currently circulating avian A(H5) influenza viruses of clade 2.3.4.4b in Europe remains low for the general public in the European Union/European Economic Area (EU/EEA). The risk of infection remains low-to-moderate for those occupationally or otherwise exposed to infected animals or contaminated environments.
