Strategic challenges in the global control of high pathogenicity avian influenza.

The 2021–2022 highly pathogenic avian influenza (HPAI) epidemic season is the largest epidemic so far observed in Europe, with a total of 2,398 outbreaks in poultry, 46 million birds culled in the affected establishments, 168 detections in captive birds, and 2,733 HPAI events in wild birds in 36 European countries. Between 16 March and 10 June 2022, 1,182 HPAI virus detections were reported in 28 EU/EEA countries and United Kingdom in poultry (750), and in wild (410) and captive birds (22). During this reporting period, 86% of the poultry outbreaks were secondary due to between‐farm spread of HPAI virus. France accounted for 68% of the overall poultry outbreaks, Hungary for 24% and all other affected countries for less than 2% each. Most detections in wild birds were reported by Germany (158), followed by the Netherlands (98) and the United Kingdom (48). The observed persistence of HPAI (H5) virus in wild birds since the 2020–2021 epidemic wave indicates that it may have become endemic in wild bird populations in Europe, implying that the health risk from HPAI A(H5) for poultry, humans, and wildlife in Europe remains present year‐round, with the highest risk in the autumn and winter months. Response options to this new epidemiological situation include the definition and the rapid implementation of suitable and sustainable HPAI mitigation strategies such as appropriate biosecurity measures and surveillance strategies for early detection measures in the different poultry production systems. Medium to long‐term strategies for reducing poultry density in high‐risk areas should also be considered. The results of the genetic analysis indicate that the viruses currently circulating in Europe belong to clade 2.3.4.4b. HPAI A(H5) viruses were also detected in wild mammal species in Canada, USA and Japan, and showed genetic markers of adaptation to replication in mammals. Since the last report, four A(H5N6), two A(H9N2) and two A(H3N8) human infections were reported in China and one A(H5N1) in USA. The risk of infection is assessed as low for the general population in the EU/EEA, and low to medium for occupationally exposed people.

Prior to the emergence of the A/goose/Guangdong/1/1996 (Gs/GD) H5N1 influenza A virus, the long‐held and well‐supported paradigm was that highly pathogenic avian influenza (HPAI) outbreaks were restricted to poultry, the result of cross‐species transmission of precursor viruses from wild aquatic birds that subsequently gained pathogenicity in domestic birds. Therefore, management agencies typically adopted a prevention, control, and eradication strategy that included strict biosecurity for domestic bird production, isolation of infected and exposed flocks, and prompt depopulation. In most cases, this strategy has proved sufficient for eradicating HPAI. Since 2002, this paradigm has been challenged with many detections of viral descendants of the Gs/GD lineage among wild birds, most of which have been associated with sporadic mortality events. Since the emergence and evolution of the genetically distinct clade 2.3.4.4 Gs/GD lineage HPAI viruses in approximately 2010, there have been further increases in the occurrence of HPAI in wild birds and geographic spread through migratory bird movement. A prominent example is the introduction of clade 2.3.4.4 Gs/GD HPAI viruses from East Asia to North America via migratory birds in autumn 2014 that ultimately led to the largest outbreak of HPAI in the history of the United States. Given the apparent maintenance of Gs/GD lineage HPAI viruses in a global avian reservoir; bidirectional virus exchange between wild and domestic birds facilitating the continued adaptation of Gs/GD HPAI viruses in wild bird hosts; the current frequency of HPAI outbreaks in wild birds globally, and particularly in Eurasia where Gs/GD HPAI viruses may now be enzootic; and ongoing dispersal of AI viruses from East Asia to North America via migratory birds, HPAI now represents an emerging disease threat to North American wildlife. This recent paradigm shift implies that management of HPAI in domestic birds alone may no longer be sufficient to eradicate HPAI viruses from a given country or region. Rather, agencies managing wild birds and their habitats may consider the development or adoption of mitigation strategies to minimize introductions to poultry, to reduce negative impacts on wild bird populations, and to diminish adverse effects to stakeholders using wildlife resources. The main objective of this review is, therefore, to provide information that will assist wildlife managers in developing mitigation strategies or approaches for dealing with outbreaks of Gs/GD HPAI in wild birds in the form of preparedness, surveillance, research, communications, and targeted management actions. Resultant outbreak response plans and actions may represent meaningful steps of wildlife managers toward the use of collaborative and multi‐jurisdictional One Health approaches when it comes to the detection, investigation, and mitigation of emerging viruses at the human‐domestic animal‐wildlife interface.

To the Editor: In 2005, a large population of wild migratory birds was infected with highly pathogenic avian influenza (HPAI) virus (H5N1) in the Qinghai Lake region of western People’s Republic of China, resulting in the death of ≈10,000 birds (1,2). On the basis of phylogenetic analysis of the hemagglutinin (HA) gene, the virus was classified as clade 2.2 according to the World Health Organization guidelines. Subsequently, viruses from this clade were found in Mongolia, Russia, Europe, and Africa along the migratory flyways of birds (3,4). This unique distribution of the same clade of HPAI virus (H5N1) through different migratory routes indicates that migratory birds might play a global role in virus dissemination (3,4). In 2006, viruses from the same clade were isolated in the Qinghai Lake region (3). Analysis of viral outbreaks along migratory flyways demonstrated a similar outbreak pattern for the past 4 years (2006–2009) (5). During that period, clade 2.2 avian influenza virus (H5N1) was isolated in China, Mongolia, Russia, Germany, Egypt, and Nigeria; all viruses were closely related to the Qinghai Lake virus. Despite the broad distribution of clade 2.2 viruses in migratory flyways, few isolates of clade 2.2 viruses in local domestic poultry were reported, especially in China (6). Outbreaks of these viruses were reported in poultry in Africa (7). The reason these viruses rarely cause outbreaks in poultry is unknown. During May–June 2009 and 2010, several dead migratory birds were found in the Qinghai Lake region. Nine HPAI viruses (H5N1) were isolated in 2009 and 2 were isolated in 2010 from great cormorants (Phalacrocorax carbo), brown-headed gulls (Chroicocephalus brunnicephalus), great black-headed gulls (Ichthyaetus ichthyaetus), great-crested grebes (Podiceps cristatus), and bar-headed geese (Anser indicus) and serotyped as described (3). HA genes from all 11 isolates were subsequently amplified by using reverse transcription–PCR and sequenced. Phylogenetic analysis of HA sequences and an additional HA gene sequence from the 2009 Qinghai Lake subtype H5N1 virus isolate from a great crested grebe (from the National Avian Influenza Virus Reference Laboratory, Harbin, China) (GenBank accession no. {type:entrez-nucleotide,attrs:{text:CY063318,term_id:301015462,term_text:CY063318}}CY063318) showed that HA genes from all 12 viruses clustered as clade 2.3.2 (Figure); none clustered with clade 2.2 viruses. Additionally, the HA cleavage site in the new isolates is PQRERRRKRG, which is identical to that of clade 2.3.2 viruses. In clade 2.2, the cleavage site is PQRERRRKKRG. Figure Bootstrapped (1,000×) maximum likelihood phylogenetic tree of hemagglutinin genes of avian influenza viruses (H5N1), People’s Republic of China, 2009–2010. Viruses isolated from the plateau pika near Qinghai Lake are indicated ... A bootstrap (1,000×) maximum likelihood tree (8) also demonstrated that Qinghai 2009 and 2010 virus isolates are closely related to those isolated in Mongolia and Uvs Nuur Lake in 2009, as reported by Sharshov et al. (5). Qinghai Lake and Uvs Nuur Lake, which are found along the migratory flyway in central Asia, are major lakes for bird migration and breeding. Many birds fly from Qinghai Lake to Uvs Nuur Lake in the spring. If one considers isolation date and bird species infected, viruses isolated in Mongolia and Russia and our isolates were likely transmitted between the 2 lake regions by bird migration. Moreover, HA sequences are closely related to viruses isolated from wild birds in Hong Kong and Japan during 2007–2008, which are the most recent isolates of clade 2.3.2 viruses before isolation of 2009 Qinghai Lake viruses. These results indicate that viruses in the Qinghai Lake region may be transmitted by wild birds along the migratory flyway in eastern Asia. However, there is no evidence that avian influenza virus (H5N1) is transmitted from eastern Asian (inner China or across the Himalayas) to the Qinghai Lake region. The 2009 and 2010 Qinghai Lake viruses are related to various viruses isolated from plateau pikas near Qinghai Lake (9). In 2007, clade 2.2 and clade 2.3.2 viruses were isolated from plateau pikas, but no clade 2.3.2 viruses were found in aquatic birds. Wild birds, pikas, and other animals near Qinghai Lake share the same environment, and viruses may be transmitted across species. However, surveillance data are limited for wild animals near Qinghai Lake. Therefore, further investigations need to be conducted to clarify relationships among birds, animals, and influenza viruses near Qinghai Lake. Our results and those of Sharshov et al. (5) show that in 2009 HPAI virus (H5N1) began infecting birds along the migratory route near Qinghai Lake and changed from clade 2.2 viruses to clade 2.3 viruses. New outbreaks of HPAI viruses (H5N1) along this migratory flyway should be investigated.

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Worldwide, wild birds are frequently suspected to be involved in the occurrence of outbreaks of different diseases in captive-bred birds although proofs are lacking and most of the dedicated studies are insufficiently conclusive to confirm or characterize the roles of wild birds in such outbreaks. The aim of this study was to assess and compare, for the most abundant peridomestic wild birds, the different exposure routes for avian influenza and Newcastle disease viruses in conservation breeding sites of Houbara bustards in the United Arab Emirates. To do so, we considered all of the potential pathways by which captive bustards could be exposed to avian influenza and Newcastle disease viruses by wild birds, and ran a comparative study of the likelihood of exposure via each of the pathways considered. We merged data from an ecological study dedicated to local wild bird communities with an analysis of the contacts between wild birds and captive bustards and with a prevalence survey of avian influenza and Newcastle disease viruses in wild bird populations. We also extracted data from an extensive review of the scientific literature and by the elicitation of expert opinion. Overall, this analysis highlighted those captive bustards had a high risk of being exposed to pathogens by wild birds. This risk was higher for Newcastle disease virus than avian influenza virus, and House sparrows represented the riskiest species for the transmission of both viruses through direct exposure from direct contact with an infectious bird that got inside the aviary and indirect exposure from consumption of water contaminated from the faeces of an infected bird that got inside the aviary for Newcastle disease virus and avian influenza virus, respectively. These results also reaffirm the need to implement biosecurity measures to limit contacts between wild and captive birds and highlight priority targets for a thoughtful and efficient sanitary management strategy.

The 2020–2021 avian influenza epidemic with a total of 3,777 reported highly pathogenic avian influenza (HPAI) detections and approximately 22,900,000 affected poultry birds in 31 European Countries appears to be one of the largest HPAI epidemics that has ever occurred in Europe. Between 15 May and 15 September 2021, 162 HPAI virus detections were reported in 17 EU/EEA countries and the UK in poultry (51), in wild (91) and captive birds (20). The detections in poultry were mainly reported by Kosovo (20), Poland (17) and Albania (6). HPAI virus was detected during the summer months in resident wild bird populations mainly in northern Europe. The data presented in this report indicates that HPAI virus is still circulating in domestic and wild bird populations in some European countries and that the epidemic is not over yet. Based on these observations, it appears that the persistence of HPAI A(H5) in Europe continues to pose a risk of further virus incursions in domestic bird populations. Furthermore, during summer, HPAI viruses were detected in poultry and several wild bird species in areas in Russia that are linked to key migration areas of wild waterbirds; this is of concern due to the possible introduction and spread of novel virus strains via wild birds migrating to the EU countries during the autumn from the eastern breeding to the overwintering sites. Nineteen different virus genotypes have been identified so far in Europe and Central Asia since July 2020, confirming a high propensity for this virus to undergo reassortment events. Since the last report, 15 human infections due to A(H5N6) HPAI and five human cases due to A(H9N2) low pathogenic avian influenza (LPAI) virus have been reported from China. Some of these cases were caused by a virus with an HA gene closely related to the A(H5) viruses circulating in Europe. The viruses characterised to date retain a preference for avian‐type receptors; however, the reports of transmission events of A(H5) viruses to mammals and humans in Russia, as well as the recent A(H5N6) human cases in China may indicate a continuous risk of these viruses adapting to mammals. The risk of infection for the general population in the EU/EEA is assessed as very low, and for occupationally exposed people low, with large uncertainty due to the high diversity of circulating viruses in the bird populations.

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There have been three waves of highly pathogenic avian influenza (HPAI) outbreaks in commercial, backyard poultry, and wild birds in Ukraine. The first (2005-2006) and second (2008) waves were caused by H5N1 HPAI virus, with 45 outbreaks among commercial poultry (chickens) and backyard fowl (chickens, ducks, and geese) in four regions of Ukraine (AR Crimea, Kherson, Odesa, and Sumy Oblast). H5N1 HPAI viruses were isolated from dead wild birds: cormorants (Phalacrocorax carbo) and great crested grebes (Podiceps cristatus) in 2006 and 2008. The third HPAI wave consisted of nine outbreaks of H5N8 HPAI in wild and domestic birds, beginning in November 2016 in the central and south regions (Kherson, Odesa, Chernivtsi, Ternopil, and Mykolaiv Oblast). H5N8 HPAI virus was detected in dead mute swans (Cygnus olor), peacocks (Pavo cristatus) (in zoo), ruddy shelducks (Tadorna ferruginea), white-fronted geese (Anser albifrons), and from environmental samples in 2016 and 2017. Wide wild bird surveillance for avian influenza (AI) virus was conducted from 2006 to 2016 in Ukraine regions suspected of being intercontinental (north-south and east-west) flyways. A total of 21 511 samples were collected from 105 species of wild birds representing 27 families and 11 orders. Ninety-five avian influenza (AI) viruses were isolated (including one H5N2 LPAI virus in 2010) from wild birds with a total of 26 antigenic hemagglutinin (HA) and neuraminidase (NA) combinations. Fifteen of 16 known avian HA subtypes were isolated. Two H5N8 HPAI viruses (2016-2017) and two H5N2 LPAI viruses (2016) were isolated from wild birds and environmental samples (fresh bird feces) during surveillance before the outbreak in poultry in 2016-2017. The Ukrainian H5N1, H5N8 HPAI, and H5N2 LPAI viruses belong to different H5 phylogenetic groups. Our results demonstrate the great diversity of AI viruses in wild birds in Ukraine, as well as the importance of this region for studying the ecology of avian influenza.

There have been three waves of highly pathogenic avian influenza (HPAI) outbreaks in commercial, backyard poultry, and wild birds in Ukraine. The first (2005-2006) and second (2008) waves were caused by H5N1 HPAI virus, with 45 outbreaks among commercial poultry (chickens) and backyard fowl (chickens, ducks, and geese) in four regions of Ukraine (AR Crimea, Kherson, Odesa, and Sumy Oblast). H5N1 HPAI viruses were isolated from dead wild birds: cormorants (Phalacrocorax carbo) and great crested grebes (Podiceps cristatus) in 2006 and 2008. The third HPAI wave consisted of nine outbreaks of H5N8 HPAI in wild and domestic birds, beginning in November 2016 in the central and south regions (Kherson, Odesa, Chernivtsi, Ternopil, and Mykolaiv Oblast). H5N8 HPAI virus was detected in dead mute swans (Cygnus olor), peacocks (Pavo cristatus) (in zoo), ruddy shelducks (Tadorna ferruginea), white-fronted geese (Anser albifrons), and from environmental samples in 2016 and 2017. Wide wild bird surveillance for avian influenza (AI) virus was conducted from 2006 to 2016 in Ukraine regions suspected of being intercontinental (north-south and east-west) flyways. A total of 21 511 samples were collected from 105 species of wild birds representing 27 families and 11 orders. Ninety-five avian influenza (AI) viruses were isolated (including one H5N2 LPAI virus in 2010) from wild birds with a total of 26 antigenic hemagglutinin (HA) and neuraminidase (NA) combinations. Fifteen of 16 known avian HA subtypes were isolated. Two H5N8 HPAI viruses (2016-2017) and two H5N2 LPAI viruses (2016) were isolated from wild birds and environmental samples (fresh bird feces) during surveillance before the outbreak in poultry in 2016-2017. The Ukrainian H5N1, H5N8 HPAI, and H5N2 LPAI viruses belong to different H5 phylogenetic groups. Our results demonstrate the great diversity of AI viruses in wild birds in Ukraine, as well as the importance of this region for studying the ecology of avian influenza.

To the Editor: Novel highly pathogenic avian influenza (HPAI) viruses of subtypes H5N2, H5N8, and H5N1 have recently caused numerous outbreaks in commercial poultry farms in the United States and Canada (1). Risk for zoonotic transmission is low; humans are affected primarily from the extensive economic repercussions of suspending poultry-farming activities (1).

Consequences and global risks of highly pathogenic avian influenza outbreaks in poultry in the United Kingdom

Influenza A viruses infect a wide range of animals including poultry, wild birds, pigs, horses, dogs, and marine mammals. Influenza in animals threatens animal health and welfare, agricultural productivity, public health, food security, and the livelihoods of farmers across the globe. The recent H1N1 pandemic of 2009, continuous reporting of zoonotic infections with highly pathogenic avian influenza (HPAI) H5N1 and other avian and swine influenza viruses, such as H3N2v, raise ongoing concerns regarding the emergence of zoonotic viruses with pandemic potential.1 Different strains of influenza A virus show host specificity and are often defined by the species in which they are initially found to be circulating. However, over time the situation becomes more complicated as the viruses continuously evolve, through mutation and reassortment, and in some cases are transmitted from species to species. The next major pandemic is likely to be caused by a strain of influenza virus that is new to that generation; a virus to which the human population has little or no immunity. Almost certainly such a strain would contain genes from influenza viruses that have been circulating in animals. A better understanding of the mechanisms responsible for interspecies transmission, and information on host adaptation and pathogenicity are needed to allow more informed assessment as to when and where the next pandemic may arise. Timely identification of viruses with pandemic potential could ultimately reduce the impact of a new pandemic. With current levels of knowledge and surveillance, it is not possible to accurately assess geographic location of all animal influenza viruses, the production systems in which they circulate, and which of these viruses may be transmitted to and adapt in the human population. This makes predictions about which strains of influenza virus to select for vaccines for pandemic preparedness a challenging task. With mortality rates reaching up to 100% in affected populations, HPAI viruses continue to have a devastating impact in poultry populations. Low-pathogenic avian influenza (LPAI) viruses also have a significant and variable impact on poultry production, depending on the strain and health status of the birds, and may evolve into HPAI viruses, for example, the recent HPAI H7N3 outbreak in Jalisco, Mexico.2, 8 These impacts together with consequential cost of control and trade measures, aimed at preventing further spread, lead to huge economic costs. There is often a greater impact on countries with a lower Gross Domestic Product (GDP), who rely on agriculture for economic development and for sustenance. Early detection of HPAI and H5 and H7 LPAI virus infections in poultry is essential for an effective response which relies on a combination of classic control measures (culling infected flocks and high risk contacts, disinfection, biosecurity, and trade measures) and, where appropriate, vaccination.3 Delays in detection lead to spiraling costs to keep epidemics under control and make the disease more difficult to eradicate. In the case of H5N1 HPAI, effective control in the animal source is needed to reduce the public health risk. Developing countries do not always have the resources to maintain the infrastructure and technical capacities needed for rapid and accurate diagnostic testing and characterization of viral strains. These countries rely on international reference laboratories to test their specimens and characterize the viruses. Research is needed to develop accurate, cheap, and robust diagnostic tests to ensure that the disease is detected early, with sufficient confidence, to allow timely initiation of effective response measures. For initial disease confirmation, both sensitivity and specificity of tests are essential because the implications of false-negative and false-positive results can be considerable. Animal influenza is not only a constraint for agriculture and food production. Equine influenza is an ongoing problem for companion and competition horses and has a huge impact on the horse racing industry. The 2007 equine influenza outbreak in Australia is estimated to have cost the horse racing and gambling industries 3·6 billion Australian dollars in lost revenue.4 Research, accompanied by increased global surveillance, is needed to ensure that the equine sector is able to access effective up-to-date vaccines so that many can continue to benefit from the enjoyment and financial gains that horse sports offer. Some suggest that historic accounts showing a temporal relationship between respiratory disease in horses and humans may implicate influenza viruses.5 However, these accounts date back to a time before influenza viruses had been isolated, and a clear link to influenza as we know it would be difficult to prove. Influenza viruses of subtype H3N8 currently circulating in the horse population have also crossed the species barrier and become established in dogs. However, this subtype and other strains of equine influenza viruses do not appear to be a significant zoonosis despite intense exposure of owners to their horses and dogs, and vice versa. An understanding of the underlying reasons for this may help to explain why other influenza viruses are zoonotic. Effective and cost-effective control require targeting resources for optimal impact. Research is needed to gain an understanding of how control measures can be better targeted. More rapid control in the animal population will limit impacts on animal health and public health when the influenza virus is zoonotic and will minimize costs in terms of production losses and access to international markets. Currently, vaccination does not always prevent infection of birds nor does it prevent infected vaccinated birds from shedding virus. If vaccines are not adequately matched antigenically to circulating field viruses and at least 60–80% of the susceptible populations are immunized, vaccination as a program will not be effective. Further research is needed to improve the effectiveness of the control measures themselves, such as vaccination, and to provide improved access to resources needed for control. Despite unprecedented levels of international investment to support avian influenza surveillance between 2004 and 2009, global surveillance for influenza viruses in animals is woefully inadequate, with too little being undertaken without adequate coordination. Improvements in surveillance are required to provide early warning for effective control and to inform much needed research.6 As well as surveillance in domestic animals (poultry, horses and pigs), surveillance in wildlife is important; it is now evident that wild birds also play a role in the primary introduction of avian influenza in previously disease-free areas.7 Today, we are not able to fully manage the threats and impacts from animal influenza. In one form or another, influenza A viruses are circulating in every country on the planet. Our understanding of the mechanisms responsible for interspecies transmission, adaptation, and pathogenicity is incomplete, and the methods for risk assessment and disease control are rudimentary. Challenges to reduce threats from animal influenzas are considerable and will only be improved through extensive research and innovation. Continued reports of notifiable avian influenza8 and animal influenza associated human infections highlight the need to monitor influenza viruses in all animal species to better understand their role in causing pandemics and severe zoonotic infections, and in reducing agricultural productivity. OFFLU is the World Organisation for Animal Health (OIE) – Food and Agricultural Organization of the United Nations (FAO) global network of expertise on animal influenza, established in 2005 to address the animal and public health threats from H5N1 HPAI. Since then, its mandate has been extended to cover all animal influenza viruses. OFFLU is unique in that its participation comprises a global representation of leading experts in animal influenza including researchers, diagnosticians, policy makers, economists, and epidemiologists. One of OFFLU's core objectives is to advocate for more research, to highlight specific influenza research objectives, promote their development, and to ensure coordination. OFFLU works closely with WHO on all influenza issues at the human–animal interface, including identifying commonly agreed research priorities. Following the OFFLU annual technical meeting in 2010 attended by avian, swine, equine, and public health experts, it was decided that there was an urgent need to develop a Research Agenda to highlight and coordinate research priorities for the animal influenza sector. The Research Agenda highlighted needs in different animal species and at the human–animal interface. It is designed to help policy makers, researchers, and donors ensure that their efforts and resources are targeted to areas where there is an identified need. The agenda should also be used to leverage funds for animal influenza research. In today's world where there is a huge volume of information of variable quality, the OFFLU Research Agenda has been designed to be concise and digestible; it comprises only 11 pages. The animal and human influenza networks share the common goal of reducing public health threats from animal influenza viruses. OFFLU has been working closely with its parent organizations, the OIE and the FAO, and its partner the World Health Organization (WHO) to ensure that its efforts are complementary and well coordinated. In 2008 and 2010, the OIE-WHO-FAO tripartite held joint technical consultations on avian influenza at the human–animal interface in Verona, Italy and discussed other technical interface topics of common interest. The experts identified that more research is needed on modes of transmission, behaviors associated with increased risks of transmission, virologic and ecologic aspects, and viral persistence in the environment to address the human exposure risks to H5N1 infection.9 Importantly in practical terms, OFFLU contributes animal influenza data to the biannual WHO influenza vaccine composition meetings. This information is critical in allowing selection of the most appropriate strains of virus for vaccines to protect against potential zoonotic pandemic influenza, including H5N1 and H9N2 avian influenza.10 Where zoonotic strains of influenza are undergoing antigenic drift in animal populations, the situation is being monitored in real time to allow selection of relevant influenza virus seed strains and antigens for vaccines for public health preparedness. OFFLU and WHO experts are working together to better understand which animal influenza viruses may pose a risk to human health. This ongoing risk assessment is supported by OFFLU's drive to improve and better collate data from avian, swine, and equine influenza surveillance programs world-wide. Animal influenza research is suffering from donor fatigue, and it is a continuing challenge to ensure that sufficient resources can be secured to address the priorities that have been identified, ultimately to improve health and economies. It is considered possible to prevent a human influenza pandemic by identifying influenza viruses with pandemic potential in animal species; this will only be achieved through further influenza research studies in animals. A large body of animal influenza data has been generated in recent years, presenting a real opportunity to increase our understanding of how to identify risk and better control the adverse effects of influenza in animals and at the human–animal interface. Many questions still remain to be answered. Structured and coordinated research toward prioritized goals and objectives will greatly facilitate this. The 'OFFLU Research Agenda' is a first for the animal health sector and will help to steer animal influenza research toward the identified objectives, providing maximum benefits for public and animal health. The influenza research priorities focus on several topics including control and education, diagnostics, epidemiology, immunology and immune responses, pathogenesis, transmission, vaccines and vaccination and virus characteristics and evolution in poultry, wild birds, swine and equine. The full OFFLU research agenda can be viewed at http://www.offlu.net/fileadmin/home/en/publications/pdf/OFFLU_Research_Priorities_photo.pdf. The authors would like to thank David Swayne, Ian Brown, Kristien Van Reeth and Ann Cullinane. The authors have no potential conflicts of interest to declare.

Surveillance APHA diseAse surveillAnce rePort HeAdlines• Cattle with multifocal skin lesions • Mesenteric torsion and tapeworms in a lamb • First outbreak this year of Klebsiella pneumoniae septicaemia in pigs • Coronavirus nephritis in adult pheasants • Seabird deaths along the British coastline • Focus on antibiotic prescribing challenges In smallholder poultry Disease surveillance in England and Wales, June 2022 About tHis rePortThis report is produced each month by the APHA Surveillance Intelligence Unit and the six Species Expert Groups (livestock and wildlife).The international horizon-scanning summaries are produced by the Defra/APHA International Disease Monitoring (IDM) team, notifiable disease reports by the APHA Veterinary Exotic and Notifiable Disease Unit (VENDU), and threat analysis by the cross-agency Veterinary Risk Group (VRG).The report is drawn from scanning surveillance information, data and reports produced by the APHA Veterinary Investigation Centres and non-APHA partner postmortem examination providers contributing to the Veterinary Investigation Diagnosis Analysis (VIDA) database and complying with standardised diagnostic and laboratory testing criteria.Other livestock and wildlife scanning surveillance reports may also be found at https://bit.ly/3vNoHV3

Between 8 December 2020 and 23 February 2021, 1,022 highly pathogenic avian influenza (HPAI) virus detectionswere reported in 25 EU/EEA countries and the UK in poultry (n=592), wild (n=421) and captive birds (n=9).The majority of the detections were reported by Francethat accounted for 442 outbreaks in poultry,mostly located inthe Landes regionandaffecting 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 cancause high mortality also in affected duck farms, mortality eventscan be seen as a good indicator of virus presence. However,also subclinical virusspread 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 circulanting in Europe based on the available sequences.Seven cases due to A(H5N8) HPAI virus have been reported from Russia, all were poultry workerswith mild or no symptoms. Five human cases due to A(H5N6) HPAI and 10 cases due to A(H9N2) LPAI viruseshave been reported from China. The risk for the general population as well as travel‐related imported human cases is assessed as very lowand the risk forpeople occupationally exposedpeople as low.Any human infections with avian influenza viruses are notifiablewithin 24 hoursthrough the Early Warning and Response System (EWRS) and the International Health Regulations (IHR) notification system.

An infectious agent affecting both domestic and wild birds may cause avian influenza. All of them can be transmitted by coming into contact with tainted food, drink, or bird emissions, particularly feces. Numerous clades of H5N1 infections have been circulating since 2003, including one introduced to the United States in 2014 by wild birds, which persisted until 2016. There were 2,240 wild birds found in 45 states and 519 counties in the United States alone by September 14, 2022. According to the World Organization for Animal Health (WOAH), the predominant Highly Pathogenic Avian Influenza (HPAI) A (H5) virus subtype causing poultry outbreaks worldwide from late 2021 to early 2022 is A (H5N1). Most notifications from wild birds across multiple countries and regions suggest that the virus may have been introduced and spread via uncontrolled bird migration. The primary instance of a goose/Guangdong/1/96-lineage H5 HPAI infection inside the Americas since June 2015 was checked by the later disclosure of an H5N1 HPAI outbreak in Newfoundland, Canada. The avian flu Type A viruses, or bird flu viruses, rarely cause human infection; some bird flu viruses have done so in the past. The HPAI (H5) virus has been persistent in wild bird populations in Europe since the 2020-21 epidemic wave, according to the paper titled “Avian Influenza Overview: March-June 2022.” Even regions like Antarctica had avian influenza cases in 2023-24. Prevention and control can be done by monitoring and reporting outbreaks, preventing avian influenza at its source in animals, banning chicken farms, controlling methodologies, remuneration for ranchers, and vaccination.