Avian flu: cases on the decline in Europe, surveillance recommended in view of upcoming season

The improvement of the situation in Europe may be linked to several factors and needs further investigation. These may include: immunity developed by wild birds following previous infection; reduction of certain wild bird populations; decreased environmental contamination; and changes in the composition of viral genotypes. 

Experts noted the continuous circulation of HPAI virus in wild birds in Europe throughout the year, albeit at low numbers. They recommended to enhance surveillance in view of the next influenza season.

HPAI outside Europe

For the first time in many years, Australia has reported HPAI cases. The different subtypes circulating in Australia are currently not reported in the rest of the world.

Experts noted the unexpected diversity of mammal species affected by HPAI as well as the different viral genotypes circulating among poultry, wild birds, and mammals in North America. Direct cattle-to-cattle transmission has not yet been confirmed, while raw milk from cows has been observed as a new, unexpected route of transmission. Current evidence indicates that industrial pasteurisation plays a significant role in inactivating HPAI virus in the raw milk of cows.