WHO is calling for heightened vigilance and strengthened surveillance efforts to prevent and detect potential human cases of avian influenza as it continues to spread in birds across Europe.

“No human cases of highly pathogenic avian influenza A(H5N8) have been reported so far in European countries, but this does not mean this cannot happen, as past experience tells us,” said Dr Caroline Brown, Programme Manager of Influenza and Other Respiratory Pathogens at WHO/Europe. “Countries reporting outbreaks in birds need to remain vigilant as avian influenza viruses can transmit from animals to humans.”

Europe’s outbreaks of influenza A(H5N8) virus in birds

Since June 2016, at least 24 countries in the WHO European Region have reported outbreaks of highly pathogenic avian influenza (HPAI) A(H5N8) virus in wild birds and domestic poultry. At least 3 of these countries have reported outbreaks in the last 2 weeks. Outbreaks have also been reported in countries in Africa, Asia and the Middle East.

This is the second time that this virus has caused outbreaks in Europe with the autumn migration of wild birds. The virus was first detected in birds in Asia in 2014, where it has continued to circulate. In June 2016 the virus was detected in waterbirds in the southern part of the Russian Federation, and by September 2016 the Food and Agriculture Organization of the United Nations had issued an alert for countries along the West Eurasian and Afro-Eurasian migration routes to watch for this virus.

Like other HPAI viruses, A(H5N8) can cause severe disease in birds, especially chickens. No human cases of avian influenza A(H5N8) have been reported to date. However, because similar influenza subtypes have caused human disease in the past, the possibility of transmission cannot be excluded.

Assessment of the risk of human transmission

The risk of transmission from birds to humans is relatively low. Although no human cases of HPAI A(H5N8) have ever been reported, it is important to remain vigilant.

Most human cases caused by other avian influenza viruses occurred after exposure through contact with infected poultry or contaminated environments, including live poultry markets. In areas with reported outbreaks of avian influenza in birds, people at potential risk are those in direct contact with/handling diseased birds and poultry, their carcasses and/or their environment.

Advice for the public in areas experiencing outbreaks in birds