Search Results (55)

Background: Highly pathogenic avian influenza (HPAI) poses a critical global threat to both the poultry industry and public health. Although Morocco currently maintains HPAI-free status, the country faces substantial risk due to its location along major migratory flyways and its extensive commercial trade networks within the poultry sector. Available data indicate that the links between live bird markets, production farms, and related facilities in the poultry sector constitute a pivotal determinant of disease epidemiology. This study aimed to analyze these movements and determine how they can influence the spread of the disease and to guide policymakers in developing effective risk-based surveillance and control strategies tailored to the local context.: A questionnaire-based cross-sectional survey was conducted across the Casablanca-Settat region, including nine provinces and 138 municipalities, to investigate the movement patterns within the poultry sector in this region. Social network analysis (SNA) was employed to construct a movement network, and findings were spatially visualized using Geographic Information Systems (GIS) and analyzed through network analysis in R.: A total of 945 transport routes were recorded in 126 municipalities. Centrality measures identified three predominant network nodes exhibiting high degree and betweenness centrality values. Our findings indicate that although the network has a low density, the transmission of IAHP remains critical due to frequent bidirectional links and a heterogeneous network structure. The high concentration of movements by a few “hub” municipalities leads to an early emergence and rapid dissemination.: The identification of highly influential nodes allows veterinary authorities to prioritize and target surveillance activities toward municipalities with the greatest likelihood of disease introduction or persistence. The network’s structural connectivity suggests a theoretical potential for rapid HPAI spread, underscoring the importance of the frequent bidirectional links identified between municipalities. This protects both Morocco’s poultry industry and public health. Full article

H9N2 low-pathogenic avian influenza viruses (LPAIV) represent an ongoing zoonotic threat due to their enzootic circulation in poultry, reassortment capacity, and increasing human transmission events. This study characterized three H9N2 isolates recovered from apparently healthy poultry in a Changchun live poultry market (September–November 2022) that exhibited unprecedented genetic and phenotypic characteristics indicating enhanced zoonotic risk. Phylogenetic analysis showed a complex mosaic genome combining segments from four distinct lineages: HA from the BJ/94-like lineage (human-associated), PB1/NP/NS from the F98-like lineage, NA from the FJ/30-C-like branch, and PB2/M genes from the G1-like lineage. Bayesian molecular clock analysis estimated the most recent common ancestor at February 2022, with HL55 and HL56 diverging by May 2022, indicating rapid local viral evolution. All isolates retained hallmark LPAIV characteristics (monobasic HA cleavage site, zero intravenous pathogenicity index in chickens). However, receptor-binding assays demonstrated a critical divergence among the isolates: while HL45 exhibited exclusive avian α2-3 receptor preference, both HL55 and HL56 retained strong avian receptor binding while additionally showing measurable affinity for human α2-6 receptors-a dual-binding phenotype associated with enhanced zoonotic potential. Most significantly, the HL55 isolate successfully infected BALB/c mice without prior adaptation, causing transient upper respiratory tract replication, moderate weight loss (~9.2%), and mild disease without mortality or systemic dissemination. These findings demonstrate that the direct mammalian infectivity of this specific mosaic H9N2 lineage adds to the growing body of evidence regarding the zoonotic potential of contemporary H9N2 variants. The presence of known mammalian-adaptation markers (PB2 A588V, NA stalk deletion, HA position 226 leucine), combined with demonstrated dual receptor-binding capacity and inherent mammalian infectivity, underscores the accelerated evolutionary trajectory of H9N2 viruses toward increased zoonotic competence. These findings warrant intensified surveillance in live poultry markets, comprehensive antigenic characterization of emerging variants, and enhanced biosecurity measures to mitigate the risk of spillover events and potential pandemic emergence. Full article

Avian influenza viruses continue to pose significant zoonotic and pandemic threat globally, with low-pathogenic avian influenza A(H9N2) being of particular concern due to sustained circulation in poultry, adaptability, and repeated human spillover. This study investigated the detection and genetic characterization of influenza viruses at the animal–human interface in Ghana in 2022, using a nationwide cross-sectional One Health approach. Samples were collected from poultry, pigs, the environment, and animal handlers across backyard farms, commercial farms, and live bird markets. Laboratory testing was conducted using real-time RT-PCR, while statistical associations were assessed using chi-square and logistic regression. Whole-genome sequencing and phylogenetic analysis were performed on selected positive samples. Out of 4056 samples, 1516 were poultry samples. A(H9N2) was detected exclusively in poultry, with a prevalence of 5.67%. The Northern belt recorded the highest prevalence. Live bird markets had significantly higher odds of A(H9N2) detection compared with commercial farms (odds ratio: 15.37, p < 0.0001), while backyard farms had lower odds. Environmental samples were negative. Among animal handlers, one case each of A(H3N2) and SARS-CoV-2 was identified. Phylogenetic analysis demonstrated that Ghanaian strains belonged to clade G1 and possessed mammalian-adaptive markers. These findings highlight ongoing circulation in poultry and the need for sustained One Health surveillance. Full article

Avian influenza remains a major threat to poultry production, wildlife conservation, and public health in Asia, where migratory birds, wetlands, rice paddies, domestic ducks, and live poultry trade often intersect. This Asia-focused review synthesizes ecological, epidemiological, surveillance, tracking, phylogenetic, and environmental evidence from 1996 to 2025, with particular emphasis on China, to clarify how risk develops at the wild bird–domestic poultry interface. The reviewed evidence suggests three broad epidemic phases: early Goose/Guangdong-lineage H5N1 outbreaks before 2014, recurrent clade 2.3.4.4 H5Nx expansions during 2014–2019, and the widespread clade 2.3.4.4b H5N1 period since 2020. Spatial risk is concentrated around major stopover wetlands and rice-paddy–duck landscapes, including Qinghai Lake, Poyang Lake, Sanmenxia, the Sanjiang Plain, and peri-urban market belts. Wetlands and paddies can maintain viruses environmentally, free-grazing ducks and bridge hosts can facilitate introduction, and live poultry markets and trade networks can amplify and export risk. By organizing these processes through an Interface–Amplifier–Conduit evidence-mapping approach, this review highlights setting-specific priorities, including seasonal wetland surveillance, closed farm-water systems, improved market hygiene, and better integration of ecological and genomic data for early warning and control. Full article

H9N2 avian influenza viruses inherently carry cross-species transmission potential, making continuous surveillance critical for pandemic prevention. This study focused on monitoring the 2024 H9N2 epidemic in Jiangsu Province’s external environment, analyzing its molecular evolution and receptor binding properties, assessing cross-species transmission and pandemic risks, and investigating serological antibody levels across different human populations. Environmental samples were collected from live poultry markets, farms, slaughterhouses, and bird habitats across Jiangsu, screened via quantitative PCR (qPCR), with positive samples used for virus isolation and whole-genome sequencing. Receptor binding properties were tested by hemagglutination assay, and H9N2 antibody levels were measured in 370 occupationally exposed individuals and 240 non-exposed individuals using hemagglutination inhibition (HI) assays. Among the 5779 collected samples, 6.89% tested H9N2-positive, and 12 strains belonging to the Eurasian lineage Y280-like clade G57 genotype were successfully isolated. All strains carried the HA-Q226L mutation, with 11 showing preferential binding to human α-2,6 receptors and one strain possessing dual receptor binding capability. Internal genes harbored mammalian adaptation mutations, and M2 proteins contained mutations conferring complete resistance to amantadine-class antiviral drugs. Serological tests revealed antibody positive rates of 4.05% in exposed populations and 2.5% in non-exposed populations, with no statistically significant difference between groups. These findings confirm that Jiangsu’s circulating H9N2 viruses have acquired human receptor preference and mammalian adaptation, posing silent infection and pandemic risks. Enhanced surveillance and the development of candidate vaccine stockpiles are strongly recommended. Full article

In tropical countries, broiler chickens are exposed to elevated ambient temperatures and humidity, which are sometimes exacerbated by high stocking densities and poor litter quality, thereby predisposing birds to severe stress, weakening immune function, and promoting BCO lameness progression. BCO lameness causes tremendous economic losses to the poultry industry and increases the risk of foodborne disease. BCO is frequently underdiagnosed in live populations, resulting in an iceberg phenomenon in which subclinical lesions are more prevalent than clinically apparent lameness. Therefore, a total of 500 Cobb500 broiler chickens from five commercial broiler flocks in Central Java, Indonesia, were randomly selected, weighed, slaughtered, and necropsied to evaluate the prevalence of BCO lameness lesions in the proximal femoral and tibial heads across distinct market ages ranging from 33 to 43 days. The ambient housing temperature in the region can reach 28–29 °C during the day. The results showed that more than 80% of the samples had normal femora at 33 days of age with an average body weight of 1.9 kg. A significant increase in the frequency and severity of femoral and tibial lesions was recorded at 35 to 36 days of age, when the average body weight reached approximately 2.5 kg. The high frequency of worsening BCO lesions observed during the 5th week suggests an age-related pattern in BCO occurrence during the late stages of grow-out. These findings suggest that improvements in nutrition, environment, and production management strategies before 36 days of age are necessary to mitigate the impact of BCO lameness in the poultry industry. Full article

H3N2 subtype avian influenza virus (AIV) is prevalent in poultry and wild birds and typically causes asymptomatic or mild respiratory infections. However, genetic reassortment between H3N2 and other AIV subtypes generates novel strains capable of crossing the species barrier, posing a threat to both poultry and public health. In this study, nine H3N2 AIVs were isolated from ducks in live poultry markets (LPMs) in Guangxi, southern China, during 2022–2024. Phylogenetic analysis revealed that all eight gene segments of the nine isolates were clustered within the Eurasian lineage, with internal genes derived from multiple subtypes, including H1, H2, H3, H4, H5, H6, H7, and H9. These findings indicate complex gene reassortment of H3N2 AIVs in Guangxi. Importantly, the PB2 genes of certain isolates were closely related to those of highly pathogenic H5 subtype viruses, suggesting that H3N2 AIVs may contribute internal genes to H5 viruses. Three representative isolates (LZD44, NND98, and NND100) were assessed for pathogenicity in SPF chickens and mice. All three strains successfully replicated in the respiratory tissues of both species. Notably, the LZD44 virus, which harbored the mammalian-adaptive mutations PB2-MVV and NP-I353V, presented significantly higher virulence in chickens and mice than the other two strains. These results demonstrate that H3N2 subtype AIVs are capable of replicating in certain tissues of chickens and mice without prior adaptation, underscoring a potential risk for cross-species transmission. Consequently, sustained surveillance of H3N2 subtype AIVs is essential to prevent the spillover of novel recombinants into the human population. Full article

The 2022 highly pathogenic avian influenza (HPAI) outbreak of H5N1 clade 2.3.4.4b was one of the major avian influenza outbreaks, leading to multiple spillover events infecting domestic and wild bird flocks, as well as mammals. The sustained spread was a result of viral circulation in wild birds across migratory flyways in North America. Pennsylvania has a significant poultry population that supports both retail and live bird markets. The state also features migratory bird stopovers on the Atlantic flyway, increasing exposure to HPAI infections. This study investigates clinical presentation and sequence data from H5N1 clade 2.3.4.4b viruses during the 2022 outbreak in Pennsylvania. Eight different H5N1 clade 2.3.4.4b genotypes were detected (A1, B1.1, B1.2, B1.3, B2.2, B3.3, B3.5, and one minor genotype) during the first year. The earliest detection was genotype A1, a fully Eurasian virus, in commercial poultry in April 2022. All other genotypes identified were reassortants of A1 with North American avian influenza gene segments (denoted with “B”). Genotype B3.3 was a rare genotype prior to the initial spillover into the live bird market system, but remained predominant among backyard flocks in Pennsylvania and surrounding states until September 2023. Genotype B3.3 has not been detected in migratory waterfowl since, suggesting the genotype has waned and is no longer in circulation. This study sheds light on the genotype diversity of H5N1 during the 2022 outbreak in Pennsylvania poultry, contributing to the understanding of virus evolution and its potential impacts. Full article

Highly pathogenic avian influenza (HPAI) is a transboundary and zoonotic viral disease affecting poultry and wild birds in many countries worldwide. Globally, HPAI outbreaks have led to the death or culling of hundreds of millions of birds over the past two decades and have caused nearly 1000 confirmed human H5N1 infections, with a case fatality rate of approximately 50%. Asia and Europe remain among the most affected regions, with recurrent outbreaks linked to intensive poultry production, live bird markets, and migratory bird pathways. In Nepal, HPAI has been reported since 2009, with more than 320 outbreaks recorded and over 2.7 million birds lost, alongside one confirmed human fatality. Control measures rely largely on stamping out, movement restrictions, and surveillance; however, gaps in farm-level biosecurity, informal cross-border poultry trade, and limited vaccination use continue to sustain vulnerability. Strengthened multisectoral coordination under a One Health framework, integrating veterinary and public health surveillance, molecular monitoring, community awareness, and risk-based biosecurity enforcement, is essential to reduce the impact of HPAI and mitigate future zoonotic and pandemic risks. Full article

Gyrovirus galga 1 (GyG1) can infect a variety of animals and humans, but prevention and control strategies are limited, which endangers the healthy development of the poultry breeding industry and has a potential impact on public health safety. The live poultry market (LPM) connects the production and consumption ends, and the pathogen may spread across regions through transportation and personnel flow. To understand the prevalence of GyG1 in Guangxi, 3482 samples from LPMs, namely, 2693 chicken throat and cloacal swabs and 789 environmental samples collected in Guangxi from December 2019 to December 2024, were assayed by PCR. The results revealed that GyG1 was present in chicken and environmental samples from LPMs in Guangxi, China, with positivity rates of 17.08% and 13.31%, respectively. Eight GyG1-positive samples were randomly selected, including 5 chicken swab samples and 3 environmental samples for whole-genome amplification. The amino acids encoded by the three ORFs were analysed, and some mutation sites unique to these 8 variants were found. The homology between the 8 GyG1 genomes and 36 reference sequences was 96.8–99.8%. The homology of the VP1 gene sequence was 96.5–99.9%, and the homology of the amino acid sequence was 99.4–100%. A phylogenetic tree was constructed on the basis of the 8 GyG1 genomes and 36 GyG1 reference genome sequences from 14 different species (8 from zoos) in this study. The 44 sequences were divided into three branches constituting groups A, B and C, with the 8 novel strains classified into group A2. Recombination analysis predicted that two recombination events in the GyG1 sequence were associated with the emergence of Guangxi strain GX-AGV2-202109-5. This study clarified the prevalence and molecular characteristics of GyG1 in LPMs in Guangxi, China, were clarified for the first time, providing important data supporting the prevention and control of GyG1 infection and providing a reference for further understanding the epidemiology and genetic diversity of GyG1. Full article

Avian influenza viruses (AIVs) pose a significant zoonotic threat, with the emerging H3N8 subtype raising increasing concern due to sporadic human infections. Current strategies for risk assessment of novel AIVs primarily rely on genetic surveillance and isolated case reports, which provide limited insight into their cross-species transmission potential. However, these approaches may overlook critical phenotypic determinants, such as pathogenicity, transmissibility, and environmental persistence, that directly influence zoonotic risk. This study investigates the evolutionary relationships, receptor-binding properties, replication dynamics, pathogenicity in mice, transmission efficiency in guinea pigs, and environmental persistence of three H3N8 strains isolated from a live poultry market. All three H3N8 strains bound exclusively to α-2,3 sialic acid receptor and achieved 100% transmissibility among guinea pigs through direct contact. Notably, the environment-origin strain A09 exhibited an indirect contact transmission efficiency of 33.3%. The findings reveal strain-specific differences, with A09 displaying enhanced pathogenicity, broader transmission routes, and greater environmental persistence compared with A05 and A01. This perspective underscores the value of integrated profiling from genotype to phenotype combined with multi-route transmission and environmental persistence analyses to delineate the adaptive roadmap of H3N8 from avian to mammalian hosts and to assess its emerging infection risk. Future directions for surveillance and intervention were also discussed, highlighting their potential to strengthen preparedness against zoonotic influenza threats. Full article

H9N2 avian influenza virus (AIV) is widely prevalent in poultry in China. To understand the genetic characteristics and evolution of H9N2 AIVs in Guangxi, southern China, the complete genomes of H9N2 AIVs from 1999–2023 were systematically analysed. Maximum likelihood (ML) trees indicated that H9N2 AIV gene sublineage diversity contributed to genotype diversity, yielding 17 genotypes (G1–G17). Since 2010, genotype G14 (also known as genotype S or G57) has become predominant in poultry in Guangxi. Phylogenetic analysis in the HA has resulted in the distancing of recent Guangxi isolates from the vaccine strains. This study also revealed that the genotypes of H9N2 AIVs infecting swine, equines and canines in Guangxi were consistent with those found in avian species at the same time, highlighting the capacity of H9N2 AIVs to be transmitted across species. The antigenic residues in the HA head region and NA protein of the Guangxi isolates from 2020–2023 changed significantly compared to the vaccine strains, suggesting possible antigenic drift in these viruses. Amino acid analysis of the HA protein revealed that 84.9% (73/86) of H9N2 AIV isolates from Guangxi, including those from live poultry markets, preferentially bound to α-2,6 sialic acid receptors. Considerable attention should be given to cross-species transmission of H9N2 AIV in the region. On the basis of these findings, strengthening the monitoring of H9N2 AIV in poultry in Guangxi is essential. Full article

Highly pathogenic avian influenza (HPAI) viruses have recently had a substantial impact on global poultry production and public health. In Egypt, clade 2.3.4.4b HPAI H5N1 viruses were first isolated from wild birds in 2021 and then became dominant in domestic poultry. In this study, we aimed to genetically characterize the H5N1 viruses isolated in Egypt during 2021–2023 and examine the pathogenicity and transmissibility of two H5N1 strains isolated from wild and domestic poultry in chickens. We collected 7588 specimens from live bird markets including poultry, wild birds, and environmental samples. Influenza A viruses were detected in 20.94% (484/2311) of tested samples, and 17 isolates were identified as H5N1 through complete genome sequencing. Phylogenetic analysis revealed that all H5N1 viruses were closely related to Eurasian viruses and classified into three distinct genetic groups, suggesting multiple introductions likely linked to migratory birds. Experimental infections of chickens with two H5N1 isolates, A/Pintail/Egypt/RA19853OP/2021 and A/duck/Egypt/BA20361C/2022, showed efficient replication, systemic infection, and transmission by direct contact. These findings underscore the need for continued surveillance of H5N1 at the poultry-wild bird interface to identify circulating strains, evaluate their biological characteristics, and assess their zoonotic potential. Full article

Background and Objectives: Avian influenza poses a continuous public health threat, particularly to individuals with occupational exposure to poultry such as farm workers, live animal market employees, and processing plant staff. This study aimed to investigate the systemic metabolic effects of such exposure and to identify potential biomarkers for early detection and health risk assessment. Materials and Methods: An untargeted liquid chromatography–mass spectrometry (LC-MS)-based metabolomics approach was applied to analyze serum samples from occupationally exposed individuals and healthy controls. Multivariate statistical analysis, pathway enrichment, and topology analysis were performed to identify significantly altered metabolites and metabolic pathways. The least absolute shrinkage and selection operator (LASSO) algorithm was employed to select key metabolites. Results: Multivariate statistical analysis revealed a clear separation between the exposure group and control, suggesting distinct metabolic profiles between the two populations. Pathway analysis indicated significant alterations in alanine, aspartate, and glutamate metabolism, as well as tryptophan metabolism, which are closely linked to immune regulation, energy metabolism, and host–pathogen interactions. LASSO feature selection and subsequent manual verification identified 17 key metabolites with strong discriminative power. Furthermore, lipidomic profiling revealed a pronounced increase in lysophosphatidylcholine (LPC) levels and a concurrent decrease in phosphatidylcholine (PC) species in exposed individuals. Conclusions: This study reveals metabolic disruptions associated with occupational avian influenza exposure and identifies potential serum biomarkers related to immune and lipid metabolism. These findings provide novel insights into host responses to avian influenza exposure and may support early detection and health risk assessment in high-risk occupational populations. Full article

Avian influenza viruses (AIVs) pose significant risks to occupational populations engaged in poultry farming, livestock handling, and live poultry market operations due to frequent exposure to infected animals and contaminated environments. This review synthesizes evidence on AIV exposure patterns and risk factors through a comprehensive analysis of viral characteristics, host dynamics, environmental influences, and human behaviors. The main routes of transmission include direct animal contact, respiratory contact during slaughter/milking, and environmental contamination (aerosols, raw milk, shared equipment). Risks increase as the virus adapts between species, survives longer in cold/wet conditions, and spreads through wild bird migration (long-distance transmission) and live bird trade (local transmission). Recommended control measures include integrated animal–human–environment surveillance, stringent biosecurity measures, vaccination, and education. These findings underscore the urgent need for global ‘One Health’ collaboration to assess risk and implement preventive measures against potentially pandemic strains of influenza A viruses, especially in light of undetected mild/asymptomatic cases and incomplete knowledge of viral evolution. Full article