ETIDIOH - NEW

Abstract Highly pathogenic avian influenza (HPAI) virus subtype H5N1 has never been detected in New Zealand . The potential impact of this virus on New Zealand's wild birds would be catastrophic. To expand our knowledge of avian influenza viruses across New Zealand, we sampled wild aquatic birds from New Zealand, its outer islands and its subantarctic territories. Metatranscriptomic analysis of 700 individuals spanning 33 species revealed no detection of H5N1 during the annual 2023-2024 migration. A single detection of H1N9 in red knots (Calidris canutus) was noted. This study provides a baseline for expanding avian influenza virus monitoring in New Zealand. Source: US National Library of Medicine,  https://pubmed.ncbi.nlm.nih.gov/40148670/ ____

On 12th September 2024, a dead Tristan (Brown) Skua (Stercorarius antarcticus hamiltoni) was found at the Gough Island helipad. The following day, a live skua was observed showing suspicious signs of HPAI , including head drooping, lethargy and weakness , and was later reported dead. Between the 12th and 15th September, a total of four skuas were found dead from suspicious causes. Three carcasses were swabbed on the 20th of September and all were confirmed POSITIVE for H5N1 HPAIV by the Animal and Plant Health Agency (Weybridge laboratory) in the UK on the 24th of October 2024. On the day of sampling, the fourth carcass could not be found and was probably taken away by a scavenging skua. Since then, no further signs of HPAI among skuas or in other seabirds breeding on Gough Island, have been observed. Source: WOAH,  https://wahis.woah.org/#/in-review/6354 ____

Highlights •  H13 HAs exhibit binding specificity for fucosylate α2-3 sialosides. •  The 130-loop and K227 are critical for H13 HA binding specificity. •  Fucosylated α2-3 sialosides are widely distributed in slaty-backed gulls. Abstract Avian influenza viruses (AIVs) recognize α2-3 sialosides as receptors . Previous studies showed that the structural diversity within α2-3 sialosides is related to the host specificity of AIVs. H13 AIVs are primarily isolated from gulls , although almost all AIV subtypes have been isolated from ducks , the natural hosts of AIVs. To elucidate the molecular basis of the host specificity of H13 viruses to gulls, the receptor-binding specificity of H13 hemagglutinins (HAs) and the distribution of viral receptors in gulls were investigated. The results revealed that recombinant HA (rHA) of H13 viruses had a binding preference for fucosylated α2-3 sialosides, which were distributed widely in the respiratory tract and intestines of gulls but not ...

ABSTRACT Background In 2021, the H5N1 clade 2.3.4.4b Avian Influenza Viruses (AIVs) emerged on the American continent. At the same time, a further global spread took place. Infections have been reported in avian species as well as in over 50 mammalian species in 26 countries , and often result in severe disease with notable neurological pathology . Outbreaks in dairy cattle in the United States in 2024 illustrate viral transmission at a non-traditional interface and cross-species transmission. This development raises significant global concern regarding the virus's potential for wider spread. Given that H5N1 infections in birds reached record-high levels in Germany by late 2022, it is important to investigate whether Influenza A Virus (IAV) infections were also occurring in mammals sharing habitats with wild birds. Methods and Results Selected wild and domestic mammal populations were monitored over a two-year period (from January 2022 to December 2023), which coincided with a majo...

 A wild Carrion Crow in Khabarovsk Region. Source:  https://wahis.woah.org/#/in-review/6304 ____

 This event will collect the detections made by sampling carried out in 2025. Peregrine falcon , adult male, transmitted to a Centre for the protection of endangered species on 05/02/2025 with nervous symptoms, that died on 06/02/2025. The necropsy was performed at the Wildlife Center for Analysis and Diagnosis. Source: WOAH,  https://wahis.woah.org/#/in-review/6316 ____

Abstract Highly pathogenic H5N1 avian influenza viruses (HPAIV) belonging to lineage 2.3.4.4b emerged in Chile in December 2022, leading to mass mortality events in wild birds, poultry, and marine mammals and one human case . We detected HPAIV in 7,33% (714/9745) of cases between December 2022–April 2023 and sequenced 177 H5N1 virus genomes from poultry, marine mammals, a human, and wild birds spanning >3800 km of Chilean coastline . Chilean viruses were closely related to Peru’s H5N1 outbreak, consistent with north-to-south spread down the Pacific coastline . One human virus and nine marine mammal viruses in Chile had the rare PB2 D701N mammalian-adaptation mutation and clustered phylogenetically despite being sampled 5 weeks and hundreds of kilometers apart . These viruses shared additional genetic signatures , including another mammalian PB2 adaptation (Q591K, n = 6), synonymous mutations, and minor variants. Several mutations were detected months later in sealions in the Atlanti...

ABSTRACT The highly pathogenic avian influenza virus (HPAIV) A(H5N1) has caused the most extensive and severe epizootic event affecting both poultry and wild birds globally. This study investigated the impact of HPAIV on the breeding population of the Black-headed Gull Chroicocephalus ridibundus , the most abundant gull species in Poland . During the 2023 outbreak, this species was reported as the most frequently infected in the country. A higher-than-natural adult mortality rate (greater than 1.5% of the breeding individuals) was observed in 114 surveyed colonies across all regions of Poland. Laboratory tests confirmed the presence of HPAIV in all 17 colonies sampled, with average adult mortality estimated at 26.1%, and ranging from 1.7% to 77.8%. The estimated mortality rate across all surveyed colonies was 22.2%. Extrapolations across the entire Polish breeding population (at least 115,000 pairs according to the national census) indicated that approximately 51,000 adult Black-headed...

A whopper swan was found dead . It was sent to the Swedish Veterinary Agency (formerly National Veterinary Institute) for laboratory analysis as part of the national surveillance program for avian influenza. Source: WOAH,  https://wahis.woah.org/#/in-review/6299 ____

Summary -- What is already known about this topic? -  Highly pathogenic avian influenza A(H5N1) outbreaks have emerged in U.S. cattle and poultry . Wastewater surveillance detects influenza A(H5) subtype but does not currently distinguish between human and animal sources. -- What is added by this report? -  During September 15, 2021–July 11, 2024 , retrospective analysis of wastewater surveillance data revealed 21 avian influenza A(H5) subtype detections across 12 Oregon communities . No association was found between detections in a community’s wastewater and history of a poultry outbreak or presence of dairy processing facilities or dairy farms within the sewershed. Avian influenza A(H5) was detected most frequently in two communities with important wild bird habitats . -- What are the implications for public health practice? -  Wastewater surveillance was an early indicator of avian influenza emergence in Oregon. Nonhuman and noncattle animal inputs , including wild bir...

{Excerpt, Feb. 26 2025 Update} 1) HPAI H5N1 was detected in a Yellow-legged Gull (Larus michahellis) found dead in the Municipality of Rimini, province of Rimini, Emilia Romagna region. 2) HPAI H5N1 was detected in an Eurasian buzzard (common buzzard) (Buteo buteo) found dead in the Municipality of Pramaggiore, province of Venezia, Veneto region 3) HPAI H5N1 was detected in a Eurasian buzzard (common buzzard) (Buteo buteo) found dead in the Municipality of Galzignano Terme, province of Padova, Veneto region 4) HPAI H5N1 was detected in a yellow-legged gull (Larus michahellis) found dead in the Municipality of Padova, province of Padova, Veneto region. 5) HPAI H5N1 was detected in a yellow-legged gull (Larus michahellis) found dead in the Municipality of Stanghella, province of Padova, Veneto region. 6) HPAI H5N1 was detected in a Yellow-legged Gull (Larus michahellis) found dead in the Municipality of Porto Recanati, province of Macerata, Marche region. "The Database of Global Adm...

Abstract Since 2020, the outbreak of highly pathogenic avian influenza (HPAI) virus clade 2.3.4.4b has turned into the largest documented panzootic to date , reaching the sub-Antarctic region and Antarctica via the tip of South America in 2023. Here, we describe its recent arrival into the Indian Ocean sub-Antarctic archipelagos of Crozet and Kerguelen , where we first detected the virus in October 2024 in dead southern elephant seals, king penguins, gentoo penguins, brown skuas and kelp gulls . While the panzootic is ongoing, it has already caused unprecedented and alarming mortalities of southern elephant seals. We collected brain swabs from various seal and bird carcasses, subsequently isolated the virus and obtained 25 novel HPAI H5N1 clade 2.3.4.4b sequences. Our phylogenetic and phylogeographic analyses show that there have been independent introductions of the virus to Crozet and Kerguelen, from the distant South Georgia Islands in the Southern Atlantic , and not from the more n...

Abstract In late 2021, Eurasian-lineage highly pathogenic avian influenza (HPAI) A(H5N1) viruses from HA clade 2.3.4.4b were first detected in the United States . These viruses have caused severe morbidity and mortality in poultry and have been detected in numerous wild and domestic animals , including cows and humans . Notably, infected cows transmitted the virus to cats , causing extreme pathogenicity and death. While human-to-human spread of the virus has not been recorded, efficient transmission of the bovine-origin virus has also led to extreme pathogenicity and death in ferret models . Recently, markers in PB2 (E627K) and HA (E186D, Q222H), indicating mammalian adaptation mutations , were detected in an H5N1-infected patient manifesting critical illness in Canada . These, combined with instances of interspecies spread of the virus , have raised global public health concerns. This could highlight the potential for the virus to successfully adapt to mammals, posing a serious risk o...

Abstract The global outbreak of clade 2.3.4.4b H5N1 highly pathogenic influenza A virus (HP H5N1) has had an unprecedented impact on wild birds including raptors , but long-term population impacts have not been addressed. To determine if raptors survive infections with HP H5N1, raptors from the upper Midwest United States were serologically tested for antibodies to influenza A virus (IAV), H5 and N1. Raptors were sampled at The Raptor Center’s (University of Minnesota) wildlife rehabilitation hospital and at Hawk Ridge Bird Observatory. Samples were tested for IAV antibodies using a commercially available blocking ELISA, with positive samples tested for antibodies to H5 and N1. Antibodies to IAV were detected in 86 out of 316 individuals representing 7 species. Antibodies to H5 and N1 were detected in 60 individuals representing 6 species . Bald eagles had the highest seroprevalence with 67/97 (69.1%) seropositive for IAV and 52 of these 67 (77.6%) testing positive for antibodies to bo...

Abstract Highly Pathogenic Avian Influenza H5N1 (HPAI H5N1) was first detected in chickens in Scottland in 1959 and has since circulated globally, causing regular outbreaks among different animal species, as well as incidental infections in humans . In this scoping review, the epidemiology and impact of HPAI H5N1 among migratory birds, poultry, and cattle in the United States were analyzed, with a particular focus on outbreaks since January 2022. Following PRISMA guidelines, a total of 27 articles were identified for this review. Publicly available data and reports from the USDA and CDC were also evaluated and summarized. The identified articles primarily included epidemiological studies of detections in wild birds, mammals, and case reports on H5N1 and transmission dynamics among cattle , with a notable absence of poultry-focused reports . Wild birds, especially migratory species, have played an important role in virus dissemination. Studies among mammals , including seals, bears, and...

A wild Barnacle Goose . The animal was found weakened on Middelkerke beach . It showed severe neurological symptoms . It was culled on suspicion of avian influenza. Source: WOAH,  https://wahis.woah.org/#/in-review/6284 ____

{Automatic Translation} Since 2020, the world has seen an increase in the number of outbreaks of avian influenza caused by the highly pathogenic avian influenza A (H5N1) virus and an expansion of the geography of circulation of this virus. In 2024, more than 1.2 thousand outbreaks of influenza A (H5N1) among wild birds and about 2 thousand outbreaks among poultry were registered in the world. The infection affected 68 countries in Asia, Europe, Africa, North and South America, and also reached Antarctica. In addition, in 2024, a large number of cases of detection of the influenza A (H5N1) virus among wild and domestic mammals were recorded, including with subsequent infection of people. These include outbreaks among cattle on US dairy farms, which by the end of the year affected more than 900 dairy farms in 16 states. The avian influenza A (H5N1) virus, isolated from cows, also caused illness in 40 people - farm workers. At the same time, the influenza A(H5N1) viruses detected in cows ...

A Great Cormorant in Leiria Region.  Backyard birds in Aveiro Region. Source: WOAH,  https://wahis.woah.org/#/in-review/6230 ____

Wild Dalmatian Pelicans in Florina Region. Source: WOAH,  https://wahis.woah.org/#/in-review/6281?reportId=172377&fromPage=event-dashboard-url ____

Abstract During our surveillance of avian influenza viruses (AIVs) in wild birds across China , H10Nx viruses were isolated from diverse migratory flyways between 2022 and 2024. We identified one wild-bird H10N5 strain that shared a common ancestor with the human H10N5 virus in multiple gene segments. Phylogenetic and molecular dating revealed the origin and evolution of H10N5, highlighting the need for continued monitoring. Source: Emerging Microbes and Infections,  https://www.tandfonline.com/doi/full/10.1080/22221751.2025.2465308 ____