An unprecedented number of highly pathogenic avian influenza (HPAI) virus detections were reported in wild and domestic birds from June to September in Europe, according to the latest overview by EFSA, the European Centre for Disease Prevention and Control, and the EU reference laboratory. In previous years, no cases or only a few cases were detected during the summer period. The overall 2021–2022 HPAI season has produced the largest epidemic so far observed in Europe.
Between 11 June and 9 September 2022, 788 HPAI virus detections were reported in 16 EU/EEA countries and the United Kingdom with 56 in poultry, 22 and 710 in captive and wild birds, respectively. The unusual persistence in wild birds continued throughout the summer and occurred in 15 European countries. The virus reached sea bird breeding colonies on the north Atlantic coast, causing massive mortality, particularly in Germany, France, Netherlands, and the UK.
Heavily infected wild birds presented an ongoing risk of infection for domestic birds too. From June to September, the number of outbreaks in domestic birds declined compared to previous months, but was more than five times higher compared to the same period the year before.
“With cases detected in poultry and wild birds up to September, the current epidemic is clearly still ongoing. As autumn migration begins and the number of wild birds wintering in Europe increases, they are likely at higher risk of HPAI infection than previous years due to the observed persistence of the virus in Europe”, said Guilhem de Seze, Head of the Risk Assessment Production Department at EFSA.
EFSA recommends the rapid implementation of suitable and sustainable HPAI mitigation strategies, including appropriate biosecurity measures and surveillance strategies for early detection. Medium to long-term prevention strategies should be considered in densely populated areas and in poultry production systems highly susceptible to avian influenza exposure.
Unprecedented geographical reach
The ongoing HPAI season has produced the largest epidemic seen so far in Europe, with a total of 2,467 outbreaks in poultry and 47.7 million birds culled in affected establishments. In addition, 187 detections were notified in captive birds and 3,573 HPAI events were recorded in wild birds. The geographical reach of this year’s epidemic is unprecedented, with reported cases ranging from the Svalbard islands in Norway to southern Portugal, and as far east as Ukraine, affecting 37 European countries in total.
In autumn 2021, the HPAI A(H5N1) virus also crossed the Atlantic Ocean for the first time, spreading from Europe to North America along migration routes and causing a severe epidemic in poultry in several Canadian provinces and US States as well as causing mortality in wild birds.
Low risk for people
The European Centre for Disease Prevention and Control (ECDC), having also contributed to the report, concludes that the risk of infection for the general human population in the EU/EEA is low, and low to medium for occupationally exposed people, with high uncertainty due to the high diversity of circulating avian influenza viruses in bird populations. The risk of transmission to humans by exposure to contaminated poultry products is considered negligible.
In addition, ECDC has published a technical report on ‘Testing and detection of zoonotic influenza virus infections in humans in the EU/EEA’, to which EFSA, the EU reference laboratory and the European Agency for Safety and Health at work have also contributed.
This news story has been updated to correct the figure about the number of birds culled in affected establishments. The correct figure is 47.7 million birds not 47.5 million birds as stated previously.