Saturday, February 27, 2021

ECDC Update: Avian Influenza Epizootic In Europe - December 2020 - February 2021


 The last 5 Avian Flu Seasons Compared - Credit ECDC


#15,836

After three years of relatively little avian flu activity in Europe (blue in chart above), the fall/winter of 2020-2021 has produced Europe's second largest avian influenza epizootic on record. The record setting avian epizootic of 2016-2017 (Light grey in chart above) was larger, but then, the season isn't over yet. 

Both of these major outbreaks were caused by clade 2.3.4.4  HPAI H5N8 and its reassortants (H5N5, H5N3, H5N1, etc.), which until very recently (see Russian Media Reports 7 Human Infections With Avian H5N8) had never been associated with human infection.

While the risk of human infection with HPAI H5N8 remains LOW or VERY LOW, the more the virus spreads, the more opportunities it has to evolve and adapt into a bigger threat.  Beyond the public health concerns, HPAI H8N8 is highly lethal in poultry, and in some types of wild birds, and the losses (either directly, or through culling) in both categories has been substantial. 

While today's report deals only with Europe and the UK, HPAI H5N8 has been burning through East Asia (particularly South Korea and Japan) the past few months, and can also be found in Russia, China, the Middle East, and Africa (see OIE map below)



The EDC scientific report runs an impressive 74 pages, and so I've only reproduced the Executive Summary below. Follow the link to download and read the report in its entirety.  I'll have a brief postscript when you return. 
Surveillance report
26 Feb 2021
Publication series: Avian influenza overview
 
Between 8 December 2020 and 23 February 2021, 1,022 highly pathogenic avian influenza (HPAI) virus detections were reported in 25 EU/EEA countries and the UK in poultry (n=592), wild (n=421) and captive birds (n=9).
Executive summary

The majority of the detections were reported by France that accounted for 442 outbreaks in poultry, mostly located in the Landes region and affecting the foie gras production industry, and six wild bird detections; Germany, who reported 207 detections in wild birds and 50 poultry outbreaks; Denmark, with 63 detections in wild birds and one poultry outbreak; and Poland, with 37 poultry outbreaks and 24 wild bird detections.

Due to the continued presence of HPAI A(H5) viruses in wild birds and the environment, there is still a risk of avian influenza incursions with the potential further spread between establishments, primarily in areas with high poultry densities.

As the currently circulating HPAI A(H5N8) virus can cause high mortality also in affected duck farms, mortality events can be seen as a good indicator of virus presence. However, also subclinical virus spread in this type of poultry production system have been reported. To improve early detection of infection in poultry within the surveillance zone, the clinical inspection of duck establishments should be complemented by encouraging farmers to collect dead birds to be pooled and tested weekly (bucket sampling).

Six different genotypes were identified to date in Europe and Russia, suggesting a high propensity of these viruses to undergo multiple reassortment events. To date, no evidence of fixation of known mutations previously described as associated to zoonotic potential has been observed in HPAI viruses currently circulating in Europe based on the available sequences.

Seven cases due to A(H5N8) HPAI virus have been reported from Russia, all were poultry workers with mild or no symptoms. Five human cases due to A(H5N6) HPAI and 10 cases due to A(H9N2) LPAI viruses have been reported from China.

The risk for the general population as well as travel-related imported human cases is assessed as very low and the risk for people occupationally exposed people as low. Any human infections with avian influenza viruses are notifiable within 24 hours through the Early Warning and Response System (EWRS) and the International Health Regulations (IHR) notification system.

While the Americas have been spared so far this year, we've seen large epizootics in the United States and Canada in the past, with the largest and most damaging coming in the spring of 2015 (see map below).



All of which means that while it is currently Europe and Asia who are battling another avian epizootic, we in North America are far from immune. The USDA has some advice on how to Defend The Flock at the website below.



And for more on how avian flu strains from Asia and Europe might make their way back into North America - either now or in the future - you may wish to revisit:


PLoS One: North Atlantic Flyways Provide Opportunities For Spread Of Avian Influenza Viruses


Posted by at