#17,545
Until recently ECDC had been publishing these highly detailed surveillance reports every 3 months (see here and here), but since last May they've begun to published a new update every 2 months.
This latest ECDC update runs 54 pages - 9 more than the last one published - and provides detailed coverage of avian flu both in Europe, and around the world.
Due to its length I've only published the link, the summary, and a couple of excerpts. Follow the link to read the report in its entirety.
Avian influenza overview April – June 2023
Surveillance report
13 Jul 2023
Publication series: Avian influenza overview
Time period covered: April - June 2023
Between 29 April and 23 June 2023, highly pathogenic avian influenza (HPAI) A(H5N1) virus (clade 2.3.4.4b) outbreaks were reported in domestic (98) and wild (634) birds across 25 countries in Europe. A cluster of outbreaks in mulard ducks for foie gras production was concentrated in Southwest France, whereas the overall A(H5N1) situation in poultry in Europe and worldwide has eased. In wild birds, black-headed gulls and several new seabird species, mostly gulls and terns (e.g. sandwich terns), were heavily affected, with increased mortality being observed in both adults and juveniles after hatching.Compared to the same period last year, dead seabirds have been increasingly found inland and not only along European coastlines. As regards mammals, A(H5N1) virus was identified in 24 domestic cats and one caracal in Poland between 10 and 30 June 2023. Affected animals showed neurological and respiratory signs, sometimes mortality, and were widely scattered across nine voivodeships in the country. All cases are genetically closely related and identified viruses cluster with viruses detected in poultry (since October 2022, but now only sporadic) and wild birds (December 2022–January 2023) in the past.Uncertainties still exist around their possible source of infection, with no feline-to-feline or feline-to-human transmission reported so far. Since 10 May 2023 and as of 4 July 2023, two A(H5N1) clade 2.3.4.4b virus detections in humans were reported from the United Kingdom, and two A(H9N2) and one A(H5N6) human infections in China.In addition, one person infected with A(H3N8) in China has died. The risk of infection with currently circulating avian H5 influenza viruses of clade 2.3.4.4b in Europe remains low for the general population in the EU/EEA, low to moderate for occupationally or otherwise exposed people to infected birds or mammals (wild or domesticated).
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Avian influenza overview April – June 2023 - EN - [PDF-2.66 MB]
Although we've heard little from Poland's Chief Veterinary Officer over the past 10 days about the surge in feline infections and deaths with H5N1, we get a summary below.
EXCERPTS (pages 25, 26)Since October 2020, the complete genome sequences of HPAI A(H5) viruses of clade 2.3.4.4b collected from 14 distinct mammalian species (European badger (Meles meles), Asian black bear (Ursus thibetanus), bush dog (Speothos venaticus), domestic cat (Felis catus), South American coati (Nasua nasua), ferret (Mustela furo), red fox (Vulpes vulpes), Eurasian lynx (lynx lynx), American mink (Neovison vison), Eurasian otter (Lutra lutra), European polecat (Mustela putorius), harbour porpoise (Phocoena phocoena), harbour seal (Phoca vitulina) and beech marten (Martes foina)) in 15 European countries have been generated.The characterised viruses belong to 8 different A(H5N1) and A(H5N8) genotypes previously identified in birds. During the 2022–2023 epidemiological year, most of the mammalian infections are caused by the three most widespread genotypes in birds, namely BB (H5N1-A/gull/France/22P015977/2022-like), AB (H5N1-A/duck/Saratov/29- 02/2021-like) and CH (H5N1-A/Eurasian_Wigeon/Netherlands/3/2022-like). Based on the available data, the vast majority of the cases detected in wild mammals, mainly red foxes, in Europe in the last months (February–May 2023) belong to genotype BB, the most frequently detected in wild birds since February 2023.About half of the characterised viruses contain at least one of the adaptive markers associated with an increased virulence and replication in mammals in the PB2 protein (E627K, D701N or T271A) (Suttie et al., 2019). These mutations have rarely been identified in the A(H5) viruses of clade 2.3.4.4b collected in birds in Europe since October 2020. This observation suggests that these mutations with potential public health implications have likely emerged upon transmission to mammals.(SNIP)HPAI A(H5N1) viruses in cats in PolandComplete genome sequences of 20 A(H5N1) virus-positive cats collected during the second half of June 2023 from six voivodeships in Poland indicate that the viruses belong to clade 2.3.4.4b, genotype CH (H5N1-A/Eurasian_Wigeon/Netherlands/3/2022-like). These viruses are highly related to each other and cluster with a virus of the same genotype detected at the beginning of June in a white stork (Ciconia ciconia) in Poland. This genotype has circulated widely in wild birds in Europe since October 2022 and, it has been responsible for several outbreaks in poultry in Poland, mainly in the Wielkopolskie area, as well as for cases in wild birds between December 2022 and January 2023.However, since February 2023, this genotype has only been sporadically identified in the country. All the viruses detected in cats possess two mutations in the PB2 protein, E627K and K526R, which are molecular markers of virus adaptation in mammals (Suttie et al., 2019). PB2-E627K has been previously demonstrated to enhance polymerase activity, virus replication, and in certain cases, pathogenicity and mortality in mammals (Subbarao et al., 1993; Hatta et al., 2001; Shinya et al., 2004; Labadie et al., 2006; Salomon et al., 2006; Hatta et al., 2007; Mehle and Doudna, 2008; Fornek et al., 2009; Li et al., 2009; RameixWelti et al., 2009; Steel et al., 2009). The same mutation is in the A(H5N1) virus detected in the white stork at the beginning of June. PB2-K526R hastbeen identified in some avian influenza viruses responsible for human cases (H5N1 and H7N9) and in the majority of theseasonal A(H3N2) human cases (Song et al., 2014).A previous study showed that A(H7N9) viruses possessing both 526R and 627K replicate more efficiently in mammalian (but not avian) cells and in mouse lung tissues and cause greater mortality in infected mice (Kobasa et al., PREPRINT (Version 1)). To date, the A(H5N1) viruses from Polish cats are the only 2.3.4.4b viruses having both mutations.
Today's report also summarizes recent human infections by H3N8, H5N6, and H9N2 as well.
A reminder that while H5N1 has the bulk of out attention, we live in a threat-rich environment, and we need to prepare for a variety of scenarios going forward.
