Pathogenic Avian Influenza Strains Research Articles

“Lights out” poultry production and pandemic influenza

AbstractPoultry production makes a substantial contribution to global food security, providing energy, protein, and essential micro-nutrients to humans. Modern intensive poultry farming systems are challenged by the evolution of Highly Pathogenic Avian Influenza strains. The presence of avian influenza in poultry flocks poses a significant risk of an avian origin influenza that is easily transmittable between human beings evolving. By reducing contact between humans and fowl, the use of automation in poultry production has the potential to improve biosecurity and thus reduce the risk of pandemic influenza. Many poultry facilities are already highly automated. The rapid rate of progress in robotics and AI suggests that “lights out”—fully automated—poultry production systems may soon be possible. In this paper we consider the ethical and policy issues that would be raised by lights-out poultry production. There is a strong animal and human welfare case for reducing the risk of pandemic influenza via increased use of automation. However, lights-out farming looks to be the ultimate endpoint of dynamics already present in industrial agriculture, which led to the dangers of zoonotic infection from animal agriculture in the first place. Whether nations should respond to that risk by doubling down on industrial models of animal production and embracing fully automated farms or by reconsidering the current model of animal agriculture altogether is, we suggest, both the most important, and the most difficult, question posed by the prospect of lights out farms.

Mitigating neglected zoonotic infections: A One Health approach on avian influenza in humans and animals

Avian influenza viruses pose a great challenge to both animal and human health. This viral disease, mainly affecting chickens and birds, poses a substantial zoonotic threat, particularly with the highly pathogenic avian influenza strain. The avian population is a key vector for viral transmission and fosters genetic changes and reassortment events that amplify the infectivity besides broadening the spectrum of host species. Infected animals shed viral particles into the environment, contributing to the widespread dissemination of the viral disease and perpetuating the persistence of viral strains. Given these factors, it is imperative to strengthen monitoring and prevention measures to curb the spread of the virus. Implementing vaccination and testing programs within the animal population, along with stringent biosecurity measures in agricultural environments, including adequate hygiene practices, controlled access to farms, and the separation of different animal species, could effectively mitigate the prevalence of circulating viruses. The measures not only reduce the risk of environmental spread but also mitigate the risk of viral transmission to humans through the One Health approach.

First Case of Highly Pathogenic Avian Influenza H5N1 in Montenegro

Abstract Avian influenza, commonly known as bird flu, is a highly infectious viral disease that affects birds, including wild water birds and poultry. The emergence and spread of highly pathogenic avian influenza (HPAI) strains, such as H5N1, have raised concerns due to their potential to cause severe outbreaks and cross the species barrier, leading to human infections and global public health emergencies. In this study, we report the first case of HPAI H5N1 detection in Montenegro. Twenty-six carcasses of dalmatian pelicans were found in Skadar Lake, Montenegro, and the H5N1 subtype was confirmed through molecular testing in the samples from pelicans. The whole influenza genome was sequenced and belonging to clade 2.3.4.4b was determined.

Global distribution, receptor binding, and cross-species transmission of H6 influenza viruses: risks and implications for humans.

The H6 subtype of avian influenza virus (AIV) is a pervasive subtype that is ubiquitously found in both wild bird and poultry populations across the globe. Recent investigations have unveiled its capacity to infect mammals, thereby expanding its host range beyond that of other subtypes and potentially facilitating its global transmission. This heightened breadth also endows H6 AIVs with the potential to serve as a genetic reservoir for the emergence of highly pathogenic avian influenza strains through genetic reassortment and adaptive mutations. Furthermore, alterations in key amino acid loci within the H6 AIV genome foster the evolution of viral infection mechanisms, which may enable the virus to surmount interspecies barriers and infect mammals, including humans, thus posing a potential threat to human well-being. In this review, we summarize the origins, dissemination patterns, geographical distribution, cross-species transmission dynamics, and genetic attributes of H6 influenza viruses. This study holds implications for the timely detection and surveillance of H6 AIVs.

Vaccination against highly pathogenic avian influenza (HPAI): From opposition to acceptance. Proceeding of The First International Avian Influenza Summit, University of Arkansas- October 16-17, 2023”

The emergence of Highly Pathogenic Avian Influenza (HPAI) strains poses a significant threat to both avian populations and human health. Vaccination has been identified as a critical tool in mitigating the spread of HPAI. However, the acceptance and implementation of avian influenza vaccination programs have been met with opposition from various stakeholders, including poultry producers, public health authorities, and consumers. This abstract provides a comprehensive overview of the evolving landscape of HPAI vaccination strategies, tracing the trajectory from initial resistance to widespread acceptance. Initially, concerns surrounding vaccine efficacy, potential adverse effects, and the economic burden associated with large-scale vaccination campaigns led to hesitancy among poultry producers and industry stakeholders. Additionally, public health authorities grappled with challenges related to regulatory approval, vaccine strain selection, and the development of robust surveillance systems. Over time, advancements in vaccine technology and extensive research demonstrating the safety and effectiveness of HPAI vaccines have gradually shifted perceptions. Adopting innovative vaccination strategies, such as vector-based vaccines and recombinant technologies, has addressed previous limitations and bolstered confidence in immunization as a viable control measure. Moreover, collaborative efforts between international organizations, governments, and research institutions have played a pivotal role in establishing standardized vaccine development, distribution, and administration protocols. These endeavors have facilitated harmonizing global strategies and enhanced the preparedness and response mechanisms for potential HPAI outbreaks. Consumer attitudes have also evolved, driven by increased awareness of the public health implications of avian influenza and a growing demand for sustainable and ethically produced poultry products. This shift in consumer sentiment has incentivized industry stakeholders to embrace vaccination as a proactive measure to safeguard both avian welfare and human health. In conclusion, this abstract highlights the transformative journey of HPAI vaccination programs, underscoring the pivotal role of scientific innovation, collaborative partnerships, and evolving consumer perspectives in overcoming initial resistance. As the global community continues to confront emerging infectious diseases, the successful trajectory of HPAI vaccination provides valuable insights into the dynamic interplay between science, policy, and public perception in the face of evolving health challenges.

An Advax-CpG adjuvanted recombinant H5 hemagglutinin vaccine protects mice against lethal influenza infection

There is a major unmet need for strategies to improve the immunogenicity of vaccines to protect against highly pathogenic avian influenza strains with pandemic potential. This study tested the ability of adjuvants based on delta inulin (Advax™) alone or combined with a TLR9 agonist (Advax-CpG™) to enhance the immunogenicity of recombinant H5 hemagglutinin antigen expressed in insect cells (rH5HA) to protect mice against lethal influenza infection. The Advax-adjuvanted rH5HA induced high serum hemagglutination inhibition activity, as well as Th1 and Th2 cytokine secreting CD4 and CD8 T cells. Immunization protected mice against a lethal heterosubtypic H5N1 virus challenge. Mice immunized with an Advax-adjuvanted rHA2 stem antigen prepared by enzymatic cleavage of rH5HA produced serum antibodies devoid of hemagglutination inhibition activity, but these anti-HA2 antibodies were nevertheless able to transfer protection against lethal H1N1 or H3N2 infections to naïve mice. We hypothesize that the enhanced protection afforded by Advax-adjuvanted rH5HA may be mediated by the combination of neutralizing antibodies directed at the HA head, anti-HA2 stem antibodies plus memory CD4 + and CD8 + T cells. This outcome supports further development of the Advax-adjuvanted rH5 pandemic influenza vaccine platform.

Immunoinformatic based designing of potential immunogenic novel mRNA and peptide-based prophylactic vaccines against H5N1 and H7N9 avian influenza viruses

Influenza viruses are the most common cause of serious respiratory illnesses worldwide and are responsible for a significant number of annual fatalities. Therefore, it is crucial to look for new immunogenic sites that might trigger an effective immune response. In the present study, bioinformatics tools were used to design mRNA and multiepitope-based vaccines against H5N1 and H7N9 subtypes of avian influenza viruses. Several Immunoinformatic tools were employed to extrapolate T and B lymphocyte epitopes of HA and NA proteins of both subtypes. The molecular docking approach was used to dock the selected HTL and CTL epitopes with the corresponding MHC molecules. Eight (8) CTL, four (4) HTL, and Six (6) linear B cell epitopes were chosen for the structural arrangement of mRNA and of peptide-based prophylactic vaccine designs. Different physicochemical characteristics of the selected epitopes fitted with suitable linkers were analyzed. High antigenic, non-toxic, and non-allergenic features of the designed vaccines were noted at a neutral physiological pH. Codon optimization tool was used to check the GC content and CAI value of constructed MEVC-Flu vaccine, which were recorded to be 50.42% and 0.97 respectively. the GC content and CAI value verify the stable expression of vaccine in pET28a + vector. In-silico immunological simulation the MEVC-Flu vaccine construct revealed a high level of immune responses. The molecular dynamics simulation and docking results confirmed the stable interaction of TLR-8 and MEVC-Flu vaccine. Based on these parameters, vaccine constructs can be regarded as an optimistic choice against H5N1 and H7N9 strains of the influenza virus. Further experimental testing of these prophylactic vaccine designs against pathogenic avian influenza strains may clarify their safety and efficacy. Communicated by Ramaswamy H. Sarma

Preclinical Study of ZSP1273, a Potent Antiviral Inhibitor of Cap Binding to the PB2 Subunit of Influenza A Polymerase.

The influenza A virus is highly contagious and often causes global pandemics. The prevalence of strains of the influenza A virus that are resistant to approved drugs is a huge challenge for the current clinical treatment of influenza A. RNA polymerase is a pivotal enzyme in the replication of the influenza A virus, and it is a promising target for anti-influenza A therapies. In this paper, we report a novel and potent anti-influenza-A-virus inhibitor, ZSP1273, targeting the influenza A virus RNA polymerase, especially for multidrug-resistant strains. The inhibitory activity of ZSP1273 on RNA polymerase activity was 0.562 ± 0.116 nM (IC50 value), which was better than that of the clinical candidate compound VX-787 with the same target. In vitro, the EC50 values of ZSP1273 on normal influenza A virus strains (i.e., H1N1 and H3N2) varied from 0.01 nM to 0.063 nM, which were better than those of the licensed drug oseltamivir. Moreover, oseltamivir-resistant strains, baloxavir-resistant strains, and highly pathogenic avian influenza strains were also sensitive to ZSP1273. In vivo, ZSP1273 effectively reduced influenza A virus titers in a dose-dependent manner in a murine model and maintained a high survival rate in mice. In addition, the inhibitory activity of ZSP1273 on influenza A virus infection was also observed in a ferret model. Pharmacokinetic studies showed the favorable pharmacokinetic characteristics of ZSP1273 in mice, rats, and beagle dogs after single-dose and continuous multiple-dose administration. In conclusion, ZSP1273 is a highly effective anti-influenza A virus replication inhibitor, especially against multidrug-resistant strains. ZSP1273 is currently being studied in phase III clinical trials.

Genome editing to create avian influenza resistance in chickens. Proceeding of The First International Avian Influenza Summit, University of Arkansas- October 16-17, 2023”

Avian influenza (AI) significantly threatens global poultry production and public health. Efforts to combat this viral disease have been predominantly focused on vaccination strategies, with limited success in controlling its spread. This study explores a novel approach utilizing genome editing techniques to enhance avian influenza resistance in chickens. Specifically, we employ CRISPR-Cas9 technology to target the ANP32 genes, endogenous proteins co-opted by influenza for replication in chicken cells. Through the precise modification of these genes, we aimed to elucidate their role in conferring resistance to low and high pathogenic avian influenza strains. We employed genome editing methodologies to introduce specific modifications in the chicken genome of reproductive cells. By introducing targeted genetic alterations in the germ cells, we created chickens that transmit their resistance trait to subsequent generations of chickens. The outcomes of this research have the potential to change avian influenza management strategies, offering a new paradigm for disease resistance in poultry populations. This approach holds promise for sustainable and cost-effective AI management strategies, reducing reliance on continuous vaccination campaigns. Moreover, the knowledge gained from our study may have broader implications for understanding host-influenza interactions in multiple species and inform future strategies for combating emerging infectious diseases at the human-animal interface.

Avian Influenza in Wild Birds and Poultry: Dissemination Pathways, Monitoring Methods, and Virus Ecology.

Avian influenza is one of the largest known threats to domestic poultry. Influenza outbreaks on poultry farms typically lead to the complete slaughter of the entire domestic bird population, causing severe economic losses worldwide. Moreover, there are highly pathogenic avian influenza (HPAI) strains that are able to infect the swine or human population in addition to their primary avian host and, as such, have the potential of being a global zoonotic and pandemic threat. Migratory birds, especially waterfowl, are a natural reservoir of the avian influenza virus; they carry and exchange different virus strains along their migration routes, leading to antigenic drift and antigenic shift, which results in the emergence of novel HPAI viruses. This requires monitoring over time and in different locations to allow for the upkeep of relevant knowledge on avian influenza virus evolution and the prevention of novel epizootic and epidemic outbreaks. In this review, we assess the role of migratory birds in the spread and introduction of influenza strains on a global level, based on recent data. Our analysis sheds light on the details of viral dissemination linked to avian migration, the viral exchange between migratory waterfowl and domestic poultry, virus ecology in general, and viral evolution as a process tightly linked to bird migration. We also provide insight into methods used to detect and quantify avian influenza in the wild. This review may be beneficial for the influenza research community and may pave the way to novel strategies of avian influenza and HPAI zoonosis outbreak monitoring and prevention.

Human influenza viruses in South-East and East Asia: a systematic review of seasonal patterns, viral types/subtypes, and antiviral susceptibility pattern in the past two decades

The study aims to evaluate influenza seasonality pattern and identify influenza viral types/subtype as well as their antiviral susceptibility pattern in South-East (SE) and East Asia (E-Asia) with the view of providing useful information for public health action. The study is a systematic review of existing literature involving the use of search engines such as Google Scholar, PubMed and EBSCOHOST. The search was conducted using a multi-stage approach which yielded 66 articles after screening for relevance to the subject using specific inclusion and exclusion criteria. A total of 60 articles were eventually analyzed and the findings were presented in tables and bar charts. The study showed that the influenza virus was more prevalent in the 6-20 years age group (SE: 53.3% and E-Asia: 44.8%) and also occurred commonly in the age of 61-90 years age group (SE: 15.6% and E-Asia: 24.1%). Seasonal peaks were reported more in the winter period with influenza A (H1N1) pdm09 (22.37%; 24.14%), seasonal influenza A (H1N1) (6.58%; 17.24%), A (H3N2) (11.84%; 17.24%), and influenza B Victoria/Yamagata (5.26%; 20.69%) being the predominant viral type/subtypes. The pathogenic avian influenza strains; AH5N1 (7.89%) and A (H7N9) (6.90%) was also reported in SE and E-Asia respectively. Oseltamivir (37.5%) and peramivir (37.04%) were the most frequently used anti-influenza agents in SE and E-Asia respectively. However, an H55Y+I436N combined mutation 4 (12.5%) and an H274Y amino acid substitution 5 (18.5%) in the neuraminidase gene of influenza A (H1N1) pdm09 was associated with decreased sensitivity to neuraminidase inhibitors. The study has shown that influenza A (H1N1) pandemic and seasonal strain, A (H3N2), and B Victoria/Yamagata remains the predominant circulating virus in SE and E-Asia. However, the dynamic antigenic and genetic evolution of the virus calls for more frequent surveillance in the region.

Major difference in clinical outcome and replication of a H3N1 avian influenza strain in young pullets and adult layers

ABSTRACTIn this study, we investigated the pathogenicity, replication and tropism of the low pathogenic avian influenza (LPAI) strain A/chicken/Belgium/460/2019(H3N1) in adult SPF layers and young SPF males. The inoculated hens showed 58% mortality and a 100% drop in egg production in the second week post inoculation. The high viral loads in the cloacal samples coincided with the period of the positive immunohistochemistry of the oviduct, acute peritonitis and time of mortality, suggesting that the replication of H3N1 in the oviduct was a major component of the onset of clinical disease and increased level of excretion of the virus. In the inoculated young birds, the clinical signs were very mild with the exception of one bird. The results suggest that the time of replication of the virus was much shorter than in the adult layers; some of the young males did not show any proof of being infected at all. To conclude, the results of the study in young birds confirmed the intravenous pathogenicity test results but also showed that the clinical signs in adult layers were very severe. Based on the mortality without a bacterial component, complete drop of egg production and post mortem findings, this H3N1 strain is a moderately virulent strain, the highest category for LPAI strains. It is important to realize that if HPAI did not exist, this moderately virulent H3N1 virus would most likely to be considered as a very virulent virus.

Comparison of the pathobiology of two different highly pathogenic avian influenza strains of different origin in geese

Comparison of the pathobiology of two different highly pathogenic avian influenza strains of different origin in geese

Unravelling the Role of O-glycans in Influenza A Virus Infection

The initial stage of host cell infection by influenza A viruses (IAV) is mediated through interaction of the viral haemagglutinin (HA) with cell surface glycans. The binding requirement of IAVs for Galβ(1,4)Glc/ GlcNAc (lactose/lactosamine) glycans with a terminal α(2,6)-linked (human receptors) or α(2,3)-linked (avian receptors) N-acetylneuraminic residue commonly found on N-glycans, is well-established. However the role and significance of sialylated Galβ(1,3)GalNAc (core 1) epitopes that are typical O-glycoforms in influenza virus pathogenesis remains poorly detailed. Here we report a multidisciplinary study using NMR spectroscopy, virus neutralization assays and molecular modelling, into the potential for IAV to engage sialyl-Galβ(1,3)GalNAc O-glycoforms for cell attachment. H5 containing virus like particles (VLPs) derived from an H5N1 avian IAV strain show a significant involvement of the O-glycan-specific GalNAc residue, coordinated by a EQTKLY motif conserved in highly pathogenic avian influenza (HPAI) strains. Notably, human pandemic H1N1 influenza viruses shift the preference from ‘human-like’ α(2,6)-linkages in sialylated Galβ(1,4)Glc/GlcNAc fragments to ‘avian-like’ α(2,3)-linkages in sialylated Galβ(1,3)GalNAc without involvement of the GalNAc residue. Overall, our study suggests that sialylated Galβ(1,3)GalNAc as O-glycan core 1 glycoforms are involved in the influenza A virus life cycle and play a particularly crucial role during infection of HPAI strains.

Comparison and analysis of sequences and structures of hemagglutinins from Influenza A Virus: a minireview

Influenza is one of the most widespread diseases in the world. The interest in Avian Influenza Virus has been increasing through the last decade because of greater than ever possibility of a pandemic outbreak. Influenza virus belongs to the Orthomyxoviridae family, which is characterized by a high variety of hemagglutinin and neuraminidase in different subtypes. Hemagglutinin has two very important sites on its surface: receptor binding site and cleavage site. In this study, we compare sequences and structures of various hemagglutinins. Emphasis was put on potential sites of mutations in functionally important domains. The possibility of adaptation of different types of influenza virus to become a pandemic strain was also evaluated. More than 50 different hemagglutinins subtypes were analyzed and compared, pointing out changes in two essential aforementioned sites. In conclusion, H9 hemagglutinin has a high potential to become a Highly Pathogenic Avian Influenza (HPAI) strain. However, H13 should also be observed because it possesses features which could result in an increase of pathogenicity

Intravenous pathogenicity of influenza virus A/H5N1/2014 isolated from pig in Ogbomoso, Nigeria.

Understanding the pathogenicity of avian influenza viruses in poultry is an important scientific and public health challenge because of antigenic shift/drift and a source of novel, potentially human-pathogenic strains. We have previously isolated an influenza A strain (H5N1/2014/Ogbomoso) from an outbreak among pig and have now aimed to assess its pathogenicity in an avian host and to categorize it as a low or high pathogenic strain. Intravenous pathogenicity index of the isolated virus was assayed using experimental infection of 6 weeks old pathogen-specific free chicken. The peak of clinical signs was on day three post-infection, and one death was observed on day eight. The intravenous pathogenicity index of this isolate was 0.08. This results classify this isolate as a low pathogenic avian influenza strain.

Pathological Alterations in Respiratory System During Co-infection with Low Pathogenic Avian Influenza Virus (H9N2) and Escherichia Coli in Broiler Chickens.

IntroductionDespite the advancements in the field, there is a lack of data when it comes to co-infections in poultry. Therefore, this study was designed to address this issue.Material and MethodsBroiler birds were experimentally infected with E. coli (O78) and low pathogenic avian influenza (LPAI) strain, alone or in combination. The experimental groups were negative control.ResultsThe infected birds showed most severe clinical signs in E. coli+LPAI group along with a significant decrease in weight and enhanced macroscopic and microscopic pathological lesions. The survival rate was 60%, 84%, and 100% in birds inoculated with E. coli+LPAI, E. coli, and LPAI virus alone, respectively. The results showed that experimental co-infection with E. coli and H9N2 strain of LPAI virus increased the severity of clinical signs, mortality rate, and gross lesions. The HI titre against LPAI virus infection in the co-infected group was significantly higher than the HI titre of LPAI group, which may indicate that E. coli may promote propagation of H9N2 LPAI virus by alteration of immune response.ConclusionThe present study revealed that co-infection with E. coli and H9N2 LPAI virus caused more serious synergistic pathogenic effects and indicates the role of both pathogens as complicating factors in poultry infections.

Risk of Human Infections With Highly Pathogenic H5N2 and Low Pathogenic H7N1 Avian Influenza Strains During Outbreaks in Ostriches in South Africa.

Risk factors for human infection with highly pathogenic (HP) and low-pathogenic (LP) avian influenza (AI) H5N2 and H7N1 were investigated during outbreaks in ostriches in the Western Cape province, South Africa. Serum surveys were conducted for veterinarians, farmworkers, and laboratory and abattoir workers involved in 2 AI outbreaks in the Western Cape province: (1) controlling and culling of 42000 ostriches during (HPAI)H5N2 outbreaks in ostriches (2011) (n = 207); (2) movement control during (LPAI)H7N1 outbreaks in 2012 (n = 66). A third serosurvey was conducted on state veterinarians from across the country in 2012 tasked with disease control in general (n = 37). Antibodies to H5 and H7 were measured by means of hemagglutination inhibition and microneutralization assays, with microneutralization assay titers >40 considered positive. Two of 207 (1%) participants were seropositive for H5 and 4 of 207 (2%) for H7 in 2011, compared with 1 of 66 (1.5%) and 8 of 66 (13%) in 2012. Although individuals in all professions tested seropositive, abattoir workers (10 of 97; 10.3%) were significantly more at risk of influenza A(H7N1) infection (P = .001) than those in other professions (2 of 171;1.2%). Among state veterinarians, 4 of 37(11%) were seropositive for H7 and 1 of 37 (2.7%) for H5. Investigations of (LP)H7N1-associated fatalities in wild birds and quarantined exotic birds in Gauteng, AI outbreaks in poultry in KwaZulu-Natal, and ostriches in Western Cape province provide possible exposure events. (LPAI)H7N1 strains pose a greater infection-risk than (HPAI)H5N2 strains to persons involved in control of outbreaks in infected birds, with ostrich abattoir workers at highest risk.

Competition between low and high pathogenicity avian influenza in a two-patch system

Over the last decade, the epidemiology of avian influenza has undergone a significant transformation. Not only have we seen an increase in the number of outbreaks of the deadly strain known as highly pathogenic avian influenza (HPAI), but the number of birds infected, and the cost of control has risen drastically. Live poultry markets play a huge role in the bird to bird transmission of avian influenza. We develop a two patch model to determine the competition between low pathogenic avian influenza (LPAI) and HPAI strains when migration is present. We define the two patches as live poultry markets in which the patches are connected through migration. We use a system of differential equations to analyze the existence-stability of the LPAI and HPAI equilibria and established results for the critical threshold R0. We observed that in general migration in both directions increases the abundance of poultry infected with the HPAI strain. Migration promotes the coexistence in Patch 2 while in Patch 1 the region of coexistence fluctuates when migration is active between both patches.

Time-space analysis of highly pathogenic avian influenza H5N2 outbreak in the US.

BackgroundIn early 2015, highly pathogenic avian influenza H5N2 caused outbreaks in commercial poultry farms in Minnesota and neighboring states where more than 48 million birds were affected. To date, the origin and transmission pathways of HPAI H5N2 have not been conclusively established.MethodsIn this study, we analyzed forty-six samples from turkeys and their environment that were collected at different time-points of the outbreak to identify origins and within outbreak evolutionary changes. We performed de-novo whole genome sequencing from primary samples and the most recent common ancestors of the PB2, PA, HA5, M and NS segments were traced back to Japanese HPAI H5N8 isolates. These segments appeared to have diverged from the ancestor around June and November 2014.ResultsThe time to most recent common ancestor analysis for PB1, NP and NA2 segments suggest two likely possibilities of reassortant HPAI H5N2 origin - either a reassortment in Alaska area or multiple reassortments with North American low pathogenic avian influenza strains, before the HPAI H5N2 outbreak strain emerged. Within the outbreak, viruses clustered into two and three subgroups suggesting high substitution rates of 0.702x10-2 - 1.665x10-2 (subs/site/year), over the 5-month outbreak period.ConclusionsData are suggestive of a fast evolving HPAI strain within an outbreak that should be taken into consideration in developing appropriate control strategies in the future.Electronic supplementary materialThe online version of this article (doi:10.1186/s12985-016-0605-4) contains supplementary material, which is available to authorized users.