#16,670
Although the United States is embroiled in its worst avian epizootic since 2015, it pales in comparison to what Europe has experienced since last fall. While we've seen just over 100 outbreaks this winter, Europe has reported nearly 3,800 across 33 countries.
Even though this year's numbers only go through March 15th, already the 2021-2022 avian flu season in Europe has nearly matched last year's record-setting numbers (see chart above), with several more months to go before the expected summer lull.
Prior to the 2016-2017 season, avian flu was only rarely reported in Europe. In a `bad year', a few dozen outbreaks might be recorded across a handful of countries.
All that changed when a reassorted, and far more capable HPAI H5N8 virus emerged out of Russia/China over the summer of 2016 (see EID Journal: Reassorted HPAI H5N8 Clade 2.3.4.4. - Germany 2016), sparking a historic avian epizootic affecting 29 European nations.
After a 3-year lull (2017-2020), HPAI has returned with a vengeance (see chart below), raising concerns that the virus has adapted enough to become endemic in wild and migratory birds.
While we get good reporting from Japan, Taiwan, South Korea, and Hong Kong, much of what happens in China and North Korea goes unreported. And unlike the H5Nx virus in Europe, some of Asia's HPAI H5 viruses can be quite deadly to humans.
With the increased avian flu activity in Europe - and a low, but non-zero risk of human infection - the ECDC and EFSA now release a detailed scientific report on HPAI every 90 days (see Dec. 2021 report). Last December they also released a new assessment where they Raised The Zoonotic Risk Potential Of Avian H5Nx.
The summary, and some excerpts from their latest (64-page) report follows. This report if chock full of data on both the European and Asian avian flu threats. I'll have a brief postscript after the break.
Avian influenza overview December 2021– March 2022
Surveillance report
31 Mar 2022Publication series: Avian influenza overview
This scientific report provides an overview of highly pathogenic avian influenza (HPAI) virus detections in poultry, captive and wild birds as well as noteworthy outbreaks of low pathogenic avian influenza (LPAI) virus in poultry and captive birds, and human cases due to avian influenza virus that occurred in and outside Europe between 9 December 2021 and 15 March 2022.
Executive summary
Between 9 December 2021 and 15 March 2022, 2,653 highly pathogenic avian influenza (HPAI) virus detections were reported in 33 EU/EEA countries and the UK in poultry (1,030), in wild (1,489) and in captive birds (133). The outbreaks in poultry were mainly reported by France (609), where two spatiotemporal clusters have been identified since October 2021, followed by Italy (131), Hungary (73) and Poland (53); those reporting countries accounted together for 12.8 of the 17.5 million birds that were culled in the HPAI affected poultry establishments in this reporting period.
The majority of the detections in wild birds were reported by Germany (767), the Netherlands (293), the UK (118) and Denmark (74). HPAI A(H5) was detected in a wide range of host species in wild birds, indicating an increasing and changing risk for virus incursion into poultry farms. The observed persistence and continuous circulation of HPAI viruses in migratory and resident wild birds will continue to pose a risk for the poultry industry in Europe for the coming months. This requires the definition and the rapid implementation of suitable and sustainable HPAI mitigation strategies such as appropriate biosecurity measures, surveillance plans and early detection measures in the different poultry production systems.
The results of the genetic analysis indicate that the viruses currently circulating in Europe belong to clade 2.3.4.4b. Some of these viruses were also detected in wild mammal species in the Netherlands, Slovenia, Finland and Ireland showing genetic markers of adaptation to replication in mammals.
Since the last report, the UK reported one human infection with A(H5N1), China 17 human infections with A(H5N6), and China and Cambodia 15 infections with A(H9N2) virus. The risk of infection for the general population in the EU/EEA is assessed as low, and for occupationally exposed people, low to medium.
Avian influenza overview December 2021– March 2022 - EN - [PDF-4.75 MB]
(Excerpt)
CONCLUSIONS
- The viruses characterised to date retain a preference for avian-type receptors; mutations associated with mammalian adaptation have only been sporadically identified in the analysed viruses from avian species, but they are frequently acquired upon transmission to mammals.
- The transmission of A(H5) clade 2.3.4.4b viruses to humans in UK, Russia and Nigeria, the increasing number of transmission events of A(H5) viruses to wild mammals reported from different European countries together with the recent upsurge of human cases due to A(H5N6) in China underline the continuous risk of avian influenza viruses to transmit to humans also in Europe and that these viruses may adapt further to mammals.
- The risk of infection for the general population in the EU/EEA is assessed as low, and for occupationally exposed people low to medium 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 as also outlined in a previous EFSA assessment (EFSA AHAW Panel, 2017).
- HPAI A(H5) continues to be maintained in wild bird populations in Eurasia, including detection in resident wild birds in Europe. Also, research on various species of dabbling ducks in Italy (Gobbo et al. 2021) showed a high prevalence of HPAI A(H5) infection in winter in geographical areas where no dead birds were detected, indicating that high infection pressure in the environment is possible in absence of wild bird mortality.
- Compared with the same period last year, in addition to migratory waterfowl, HPAI A(H5) was detected in a wider range of other wild bird species, including several terrestrial species. This enlarged host range of HPAI A(H5) in wild birds indicates an increasing and changing risk for virus incursion into poultry farms.
- The dynamics of the current HPAI epidemic compared with those observed in 2016–2017 and 2020–2021 indicate that an elevated environmental pressure of infection will likely persist in the coming months posing a risk for further virus introduction and spread in the poultry sector.
- The frequent occurrence of HPAI A(H5) virus incursions in commercial farms where birds are kept indoors, including poultry production types considered at low avian influenza risk (e.g. broilers), raises concern about the capacity and effectiveness of applied biosecurity measures to prevent virus introduction.
But until 2003, we'd seen zero evidence that coronaviruses presented any realistic pandemic threat. Since then the emergence of SARS-CoV, MERS-CoV, and SARS-CoV-2 has elevated them to a top-tier threat.
Even if HPAI never sparks a pandemic, it can be devastating for the poultry industry, strain local economies, and spark food insecurity. All reasons why we need better global surveillance and reporting on this rising threat.
