Highly pathogenic avian influenza A(H5N1) remained at relatively low levels in European birds during summer 2026, but the global picture was more dynamic. The latest joint ECDC-EFSA assessment highlights continued spillover into mammals, persistent circulation in U.S. dairy cattle and further expansion of H5N1 in Australia.
The report covers animal detections from 5 June to 28 August 2026 and human cases reported up to 31 August.
In Europe, 110 HPAI A(H5N1) detections were recorded in birds across 12 countries. Most involved wildlife: 103 detections in wild birds and only seven in domestic birds. Activity remained at a seasonal low throughout the summer, with fewer detections in colony-breeding seabirds and a more restricted geographical distribution than in previous high-transmission periods.
Mammalian infections remain a key concern
Despite the decline in avian detections, sporadic HPAI A(H5) infections continued to be reported in wild terrestrial carnivores and pinnipeds in Europe.
These cases remain important because each mammalian infection provides another opportunity for influenza viruses to adapt outside their traditional avian hosts. The report found no evidence of sustained mammal-to-mammal transmission in Europe, but continued genomic surveillance is considered essential.
Outside Europe, the situation was more active.
In the United States, the number of dairy cattle farms affected by H5N1 continued to increase during the reporting period. The persistence of the virus in cattle remains one of the most significant changes in H5N1 epidemiology, because it represents sustained circulation in a major domestic mammalian species.
The report also records the first H5N1 detections in captive American mink in the United States.
Australia: H5N1 moves into mammals
Australia represents another important development. Following its recent introduction onto mainland Australia, H5N1 spread among local wild birds and subsequently spilled over into terrestrial carnivores and marine mammals.
This is particularly significant because Australia had remained outside the global clade 2.3.4.4b H5N1 panzootic for several years. Its involvement now extends the virus to another major geographical region and creates a new setting for monitoring cross-species adaptation.
Fifteen human infections reported
Between 5 June and 31 August, 15 human infections with avian influenza viruses were reported:
Bangladesh: 1 H5N1 case
Cambodia: 1 H5N1 case
China: 13 H9N2 cases
No deaths were reported. All patients had a history of exposure to poultry or poultry environments before illness. No sustained human-to-human transmission was identified. ECDC therefore continues to assess the risk from currently circulating H5N1 viruses as low for the general EU/EEA population and low to moderate for people occupationally exposed to infected animals or contaminated environments.
Source: ECDC/EFSA, Avian influenza overview June-August 2026
https://www.ecdc.europa.eu/en/publications-data/avian-influenza-overview-june-august-2026
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