#15,479
Since early August we've been following reports of outbreaks of Highly Pathogenic Avian Influenza (HPAI) in southwestern Russia and northern Kazakhstan.
Some of these outbreaks have been identified as HPAI H5N8, while others are only labeled H5Nx. In the past, we've also seen HPAI H5N1, HPAI H5N2, and HPAI H5N6 reported in these regions.
A smattering of recent blogs include:
While avian flu has been on the decline in Europe since their record-breaking HPAI H5 outbreak ended in the spring of 2017, these recent reports are reminiscent of the run-up to that 2016-2017 epizootic (see OIE: Russia - HPAI H5 In Wild & Migratory Birds), which saw a highly virulent reassorted HPAI H5N8 virus arrive in Europe that fall.
Once considered controversial, today there is little debate that HPAI viruses are spread over long distances by migratory birds (see WHO: Migratory Birds & The Potential Spread Of Avian Influenza).
The major migratory bird flyways (shown below) - along with scores of minor pathways not depicted - serve as a global interstate highway for avian influenza viruses. While primarily north-south conduits, there is enough overlap to allow for east-west movement as well.
A study, published in 2016 (see Sci Repts.: Southward Autumn Migration Of Waterfowl Facilitates Transmission Of HPAI H5N1), suggests that waterfowl pick up new HPAI viruses in the spring (likely from poultry or terrestrial birds) on their northbound trip to their summer breeding spots - where they spread and potentially evolve - and then redistribute them on their southbound journey the following fall.
Russian language media reports continue to come out of Kazakhstan and southern Russia (see Avian influenza covered 16 districts of the Omsk region) suggesting the outbreak continues to worsen, leading the ECDC and the EFSA (European Food Safety Agency) to issue warnings yesterday.
First stop, the ECDC, which released two reports. First a surveillance report (which only covers European avian flu activity up to August 15th).
Surveillance report30 Sep 2020Publication series: Avian influenza overviewTime period covered: 16 May - 15 August 2020
Between 16 May and 15 August 2020, seven highly pathogenic avian influenza (HPAI) A(H5N8) virus outbreaks were reported in Europe in poultry, with one outbreak reported in Bulgaria (n=1) and six in Hungary (n=6) and one low pathogenic avian influenza (LPAI) A(H5N3) virus outbreak was reported in poultry in Italy.
Avian influenza overview May – August 2020 - EN - [PDF-1.95 MB]
This 40-page PDF is well worth downloading and reading in its entirety. It acknowledges a general lack of information about the recent avian flu activity in Kazakhstan and Russia, citing:
- The repeated detection of HPAI A(H5N8) or A(H5) in domestic and wild birds in western Russia and north Kazakhstan between July and September 2020 indicates either ongoing local circulation of HPAI viruses or new virus introductions by infected wild birds. The mortality observed in corvids in North Kazakhstan (which probably were exposed by feeding on infected carcasses) is indicative of a significant virus circulation in the area.
- The presence of HPAI virus in western Russia and north Kazakhstan, spatially associated with autumn migration routes of wild waterbirds and the previous detection of HPAI virus in mute swans in northern China (EFSA et al., 2020a), also linked to key migration areas, is of concern due to the possible spread of the virus via wild birds migrating to the EU.
- The scarce information on the wild birds species found dead makes difficult to identify the most probable migratory flyways that might lead to the introduction of the virus in the EU and therefore to identify the area in the EU that are at higher risk of virus introduction. Nonetheless, during the 2005-2006 and 2016-2017 epidemic waves, HPAI virus detection in the same area of Russia between July and September (OIE, 2005; Lipatov et al., 2007; FAO, 2016) lead to northern and eastern Europe being detected as first places of virus introduction (Cattoli et al., 2009; EFSA et al., 2017b), and they will likely be the first areas where HPAI viruses might be detected in the coming autumn-winter season.
- Sudden and persistent drop in the temperatures in Russia and Kazakhstan may favour a westward/southward spread of the virus. Several studies demonstrated that cold weather conditions might have triggered the rapid westward expansion of the HPAI A(H5) virus by infected migratory birds during the 2005-2006 and 2016-17 epidemic waves (Ottaviani et al., 2010; Fusaro et al., 2017; Napp et al., 2018).
All of which brings us to the following ECDC news release:
Avian influenza: EU on alert for new outbreaks
News story
30 Sep 2020
EU states are being urged to step up surveillance and biosecurity measures to guard against possible new outbreaks of avian influenza this year.
The warning follows outbreaks of highly pathogenic avian influenza (HPAI) among wild and domestic birds in western Russia and Kazakhstan over the past few months. This region is a known autumn migration route for wild water birds heading to Europe.
Northern and eastern Europe are likely to be the most vulnerable to new outbreaks given past experience. When HPAI was detected in the same area of Russia in the summers of 2005 and 2016, epidemics followed in northern and eastern Europe. If the pattern is repeated this year, HPAI is expected to arrive in the same areas of Europe in autumn or winter. Subsequent spread to countries in southern and western Europe is also possible.
The alert is included in the latest update on avian influenza in Europe and beyond. The new report – which is compiled by EFSA, the European Centre for Disease Prevention and Control (ECDC) and the European Union Reference Laboratory for Avian Influenza – covers the period May to August 2020.
The report recommends that EU countries should:
- Take measures to detect suspected cases of HPAI promptly and increase biosecurity measures at poultry farms.
- Warn veterinary and wildlife health authorities of the likely risk of HPAI introduction, and urge them to carry out prompt testing of dead or sick wild birds.
Spread of the virus is likely to be triggered by a sudden and persistent fall in temperatures in central Russia and Kazakhstan. Several studies demonstrate that cold weather conditions led to the rapid westward expansion of the HPAI virus by infected migratory birds during the 2005-2006 and 2016-2017 waves.
The risk of transmission of avian influenza viruses to the general public in Europe remains very low. However, to minimise the risk of transmission to humans, people are advised not to not touch dead birds without wearing appropriate personal protective equipment.
The same warning appears on the EFSA website.
Avian flu activity tends to be highly variable, with large regional outbreaks often followed by one or more years of reduced activity. Europe's last big outbreak was the winter of 2016-2017, while North America's last avian epizootic was over the winter of 2014-2015.
China's massive H5+H7 poultry vaccination campaign - which began in the summer of 2017 - has likely further contributed to the recent global decline in avian flu activity.
But influenza viruses continue to evolve, and migratory birds continue to fly. This respite - as welcome as it has been - won't last forever. And while it is Europe that is receiving the warning today, the next epizootic could appear anywhere in the world.
