Eight European countries have reported highly pathogenic avian influenza (HPAI) strain A/H5N8 in wild birds, zoo birds and poultry holdings.
This is the second time this virus has been introduced into Europe via the autumn migration of wild birds, although the H5N8 strain has been circulating continuously in Asia since 2010, according to the European Centre for Disease Prevention & Control (ECDC).
Full genome sequencing of recent A/H5N8 viruses suggest that these remain essentially avian viruses without any specific increased risk for humans, ECDC reported, and no human infections with this virus have ever been reported worldwide.
ECDC recently updated its rapid risk assessment, concluding that the risk of transmission to the general public in Europe is considered to be very low.
HPAI A/H5N8 viruses cluster in the same hemagglutinin clade as A/H5N1 viruses from Asia and A/H5N6 — which has caused severe disease in humans in China — so the possibility of transmission from birds to humans cannot be completely ruled out, ECDC explained. People in direct contact with or handling diseased birds or poultry and their carcasses may be at risk of infection.
Given this potential zoonotic risk, ECDC said control measures for avian influenza in poultry and birds are being implemented by the affected countries to ensure that persons at risk are sufficiently protected from infection.
An increased mortality in wild birds in Europe has been observed compared to the first reports of A/H5N8 in 2014-15. On Oct. 27, 2016, authorities in Hungary reported the detection of HPAI A/H5N8 in a wild swan.
Further notifications of HPAI A/H5N8 viruses detected in wild birds and poultry holdings have been made by seven additional European countries. Austria, Hungary and Germany reported outbreaks in poultry and detections in wild birds. Croatia, Denmark, Poland and Switzerland reported infection in wild birds only, while the Netherlands detected HPAI A/H5N8 in wild birds and birds in a zoo. India and Israel are currently reporting outbreaks in birds while South Korea, Taiwan and Russia reported outbreaks earlier this year. Culling of the affected poultry in European countries is ongoing or completed; protection zones and surveillance zones have been established.
Ongoing monitoring and testing of wild birds and domestic poultry in the European Union plays an important role in the detection and protection against exposure and subsequent spread of the virus in poultry across Europe. This may equally minimize the human risk via exposure to infected birds.