Avian influenza: increased spread in poultry-dense areas at end 2024

Avian influenza: increased spread in poultry-dense areas at end 2024

While there continues to be no evidence of human-to-human spread of avian influenza, new outbreaks in wild and domestic birds were reported in Europe and around the world between September and December 2024. These are the main findings of our last avian influenza monitoring report, produced together with the European Centre for Disease Prevention and Control (ECDC) and the EU reference laboratory (EURL).

Situation in Europe

Although the overall number of avian influenza cases remains low compared to previous years, the last quarter of the year saw an increase in cases in wild and domestic birds compared to the previous quarter. Most of the detections in both wild and domestic birds were found in South-Central Europe, mainly in areas with a high concentration of poultry farms. Our experts concluded that the large number of farms in these areas and the type of poultry production contributed to disease spread between farms. A(H5N5) virus, a subtype of the avian influenza virus which causes mass mortality in wild birds, has significantly expanded its geographical and species A subdivision of the genus, a species is a group of closely related and similar-looking organisms; for example, in the case of Homo sapiens (humans), the second part of the name (sapiens) represents the speciesrange, spreading widely in different regions and wild bird species. However, no new cases have been reported in mammals.

According to ECDC, the risk of infection is currently low for the general public in Europe, and low to medium for people working with or exposed to infected animals or contaminated environments.

Situation in the US

Outside of Europe, the US is seeing a significant surge in cases among cattle, with more than 800 establishments affected in 16 states. Most of the cases are reported in California where the virus was also recently found in two batches of raw milk sold in retail shops. Additionally, A (H5N1) virus strain A subtype of a microbe defined by its genetic make-up; for example, in the case of Escherichia coli O157, the 'O157' part of the name refers to the strain, which is different from the one affecting cattle, was detected for the first time in pigs in Oregon in a mixed livestock-poultry farm. This is of concern given the potential for pigs to be co-infected by different types of influenza viruses that could adapt and spread to other species.

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