Highly pathogenic avian influenza virus of the A/H5N8 subtype, clade 2.3.4.4b, caused outbreaks in Kazakhstan in 2020

Spatiotemporal genotype replacement of H5N8 avian influenza viruses contributed to H5N1 emergence in 2021/2022 panzootic

Since 2020, clade 2.3.4.4b highly pathogenic avian influenza H5N8 and H5N1 viruses have swept through continents, posing serious threats to the world. Through comprehensive analyses of epidemiological, genetic, and bird migration data, we found that the dominant genotype replacement of the H5N8 viruses in 2020 contributed to the H5N1 outbreak in the 2021/2022 wave. The 2020 outbreak of the H5N8 G1 genotype instead of the G0 genotype produced reassortment opportunities and led to the emergence of a new H5N1 virus with G1's HA and MP genes. Despite extensive reassortments in the 2021/2022 wave, the H5N1 virus retained the HA and MP genes, causing a significant outbreak in Europe and North America. Furtherly, through the wild bird migration flyways investigation, we found that the temporal-spatial coincidence between the outbreak of the H5N8 G1 virus and the bird autumn migration may have expanded the H5 viral spread, which may be one of the main drivers of the emergence of the 2020-2022 H5 panzootic.IMPORTANCESince 2020, highly pathogenic avian influenza (HPAI) H5 subtype variants of clade 2.3.4.4b have spread across continents, posing unprecedented threats globally. However, the factors promoting the genesis and spread of H5 HPAI viruses remain unclear. Here, we found that the spatiotemporal genotype replacement of H5N8 HPAI viruses contributed to the emergence of the H5N1 variant that caused the 2021/2022 panzootic, and the viral evolution in poultry of Egypt and surrounding area and autumn bird migration from the Russia-Kazakhstan region to Europe are important drivers of the emergence of the 2020-2022 H5 panzootic. These findings provide important targets for early warning and could help control the current and future HPAI epidemics.

Spatio-temporal evaluation of social media as a tool for livestock disease surveillance

Recent outbreaks of Avian Influenza across Europe have highlighted the potential for syndromic surveillance systems that consider other modes of data, namely social media. This study investigates the feasibility of using social media, primarily Twitter, to monitor illness outbreaks such as avian flu. Using temporal, geographical, and correlation analyses, we investigated the association between avian influenza tweets and officially verified cases in the United Kingdom in 2021 and 2022. Pearson correlation coefficient, bivariate Moran's I analysis and time series analysis, were among the methodologies used. The findings show a weak, statistically insignificant relationship between the number of tweets and confirmed cases in a temporal context, implying that relying simply on social media data for surveillance may be insufficient. The spatial analysis provided insights into the overlaps between confirmed cases and tweet locations, shedding light on regionally targeted interventions during outbreaks. Although social media can be useful for understanding public sentiment and concerns during outbreaks, it must be combined with traditional surveillance methods and official data sources for a more accurate and comprehensive approach. Improved data mining techniques and real-time analysis can improve outbreak detection and response even further. This study underscores the need of having a strong surveillance system in place to properly monitor and manage disease outbreaks and protect public health.

Molecular characterization and phylogenetic analysis of highly pathogenic H5N1 clade 2.3.4.4b virus in Bosnia and Herzegovina

Influenza A virus continues to represent a growing problem affecting mainly birds but with an increasing number of mammal transmission events reported each year. Nevertheless, molecular characterization and phylogenetic analysis of influenza A viruses originating from all confirmed cases have not been systematically performed in all parts of the world. In this study, we investigated a sample originating from a mute swan that died in November 2021 in the northern part of Bosnia and Herzegovina with RT-qPCR and whole genome sequencing using ONT MinION. It was diagnosed as a highly pathogenic Influenza A virus, subtype H5N1 of 2.3.4.4b clade, and phylogenetic analysis revealed high sequence homology with other European HPAI H5N1 sequences at the time. The notable detected mutations in HA (N110S and T139P) and NA genes (H155Y), that facilitate the host specificity shift and enable the resistance to some antiviral drugs respectively, underscore the necessity of virus evolution surveillance. Therefore, the rapid dissemination of information, including virological and molecular data, is essential for the introduction of tailored prevention measures for infected animals, providing clearer insight and better awareness of a potential public health threat.

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.

Genome Sequence of Highly Pathogenic Avian Influenza Virus A/Chicken/North Kazakhstan/184/2020 (H5N8)

The influenza virus strain A/chicken/North Kazakhstan/184/2020 (H5N8) was isolated in North Kazakhstan during a highly pathogenic avian influenza outbreak in 2020. This study aimed to obtain the complete genome sequence of the isolate.

The global prevalence of highly pathogenic avian influenza A (H5N8) infection in birds: A systematic review and meta-analysis

The zoonotic pathogen avian influenza A H5N8 causes enormous economic losses in the poultry industry and poses a serious threat to the public health. Here, we report the first systematic review and meta-analysis of the worldwide prevalence of birds. We filtered 45 eligible articles from seven databases. A random-effects model was used to analyze the prevalence of H5N8 in birds. The pooled prevalence of H5N8 in birds was 1.6%. In the regions, Africa has the highest prevalence (8.0%). Based on the source, village (8.3%) was the highest. In the sample type, the highest prevalence was organs (79.7%). In seasons, the highest prevalence was autumn (28.1%). The largest prevalence in the sampling time was during 2019 or later (7.0%). Furthermore, geographical factors also were associated with the prevalence. Therefore, we recommend site-specific prevention and control tools for this strain in birds and enhance the surveillance to reduce the spread of H5N8.

Epidemiological characteristics and financial losses due to avian aspergillosis in households in the Almaty region, Republic of Kazakhstan

Aspergillosis is a severe fungal disease that affects all species and ages of poultry and leads to significant economic losses within the poultry industry. The economic significance of aspergillosis is associated with direct losses due to poultry mortality, a decline in the production of meat and eggs, feed conversion, and poor growth of recovering poultry. Although a decrease in the production of poultry meat and eggs in Kazakhstan due to this fungal disease has been widely reported, studies on the consequent financial losses on affected farms (households) have not been carried out. This study aimed to estimate the financial losses and epidemiological parameters of avian aspergillosis among households affected by the disease in the Almaty region. To achieve the objectives of the research, a survey was conducted involving affected households from February 2018 to July 2019. The affected poultry were diagnosed based on clinical, macroscopical, and microscopical procedures, and once the infection was confirmed, household owners were interviewed. Data were collected from 183 household owners. The median incidence risk and fatality rates were 39 and 26% in chickens, 42 and 22% in turkeys, and 37 and 33% in geese, respectively, with young poultry having a higher incidence risk and fatality rate than adults. Approximately 92.4% of the household owners treated the affected poultry using natural folk methods and 7.6% of household owners used antifungal drugs and antibiotics, spending a median of US $35.20 (min US $0; max US $400) per household throughout the course of the infection. Egg production was reduced by a median of 58.3% when households were affected. The price of poultry fell by a median of 48.6% immediately after recovery due to weight loss. The median of the overall financial losses of households was US $198.50 (min US $11; max US $1,269). The majority of household owners (65%) did not replace their poultry, 9.8% of household owners replaced all their poultry, and the remaining 25.1% replaced only a proportion of the poultry lost at the time of the study. Newly acquired poultry were purchased from neighbors (10.9%), fellow villagers (50%), and state poultry farms (39.1%). This study demonstrates that aspergillosis has an immediate impact on subsistence household owners' livelihoods in the Almaty region of Kazakhstan.

An early warning system for highly pathogenic viruses borne by waterbird species and related dynamics of climate change in the Caspian Sea region: Outlines of a concept

Aim. Formulation of the outlines of the concept of ViEW (Viral Early Warning) which is intended as a long term system of multidisciplinary transboundary cooperation between specialist institutions of all five Caspian region states to research, regularly monitor and share data about the generation, transmission and epidemiology of avian‐borne pathogens and their vectors in the region, and the ways climate change may affect these processes.

Material and Methods. The concept is based on the multidisciplinary experience of the authors in researching the processes incorporated in the ViEW concept and on an in‐depth survey of the literature involved.

Results. The outlines of the ViEW concept are presented in this study for review and comment by interested parties and stakeholders.

Conclusion. Review of activities and opinions of specialists and organizations with remits relating to the development, establishment and maintenance of ViEW, indicates that such a system is a necessity for global animal and human health because of the role that the Caspian region plays in the mass migration of species of waterbird known as vectors for avian influenza and the already evident impacts of climate change on their phenologies. Waterbirds frequenting the Caspian Sea littorals and their habitats together constitute a major potential global hotspot or High Risk region for the generation and transmission of highly pathogenic avian influenza viruses and other dangerous zoonotic diseases.

Evidence for flock transmission of individual subtypes and strains of avian influenza viruses: A monitoring study of wild birds in Kazakhstan

An active surveillance study of avian influenza viruses (AIVs) in wild birds was carried out in Kazakhstan in 2018-2019. In total, 866 samples were collected from wild birds and analyzed for influenza viruses using molecular and virological tests. Genome segments of Asian, European, and Australian lineages were detected in 25 (4.6%) out of 541 waterfowl samples positive for subtype H3N8, and in two (0.6%) out of 325 H3N8 positive samples from terrestrial birds. No highly pathogenic avian influenza virus (AIV) was detected. The results indicated transmission of closely related strains or identical subtypes of AIVs by a flock-unit of migratory birds or annual cyclical pattern of subtype dominance. The simultaneous circulation of genome segments of the Asian, European and Australian genetic lineages of H3N8 AIVs in wild birds in Kazakhstan indicated the important role of Central Asia as a transmission hub of AI viruses linking the East Asian migratory flyways with European flyways and vice versa.