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H9N2 is the most widespread avian influenza virus subtype in poultry worldwide. It infects a broad spectrum of host species including birds and mammals. Infections in poultry and humans vary from silent to fatal. Importantly, all AIV, which are fatal in humans (e.g. H5N1, H7N9) acquired their ‘internal’ gene segments from H9N2 viruses. Although H9N...
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... in ME and NA covered in this review include Iran, Iraq, Kuwait, Qatar, United Arab Emirates (UAE), Oman, Bahrain, Yemen, Saudi Arabia (SA), Jordan, Palestine, Israel, Syria, Lebanon, Turkey, Egypt, Sudan, Libya, Tunisia, Algeria and Morocco (Fig. 1). The total human population of ME and NA was estimated in 2016 by the UN to be 0·55 billion representing 7·4% of the world population [27]. Egypt is the most populated country with 93 million inhabi- tants followed by Iran and Turkey with about 80 mil- lion each [27]. The ME and NA countries extend on about 14·4 million km 2 , ...
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... in ME and NA are located along several wild birds' migratory flyways. Four major flyways are the Central Asia, East-Africa West-Asia, Black-Sea Mediterranean and East Atlantic routes which intersect with other pathways (e.g. East Asia-Australian flyway) (Fig. 1). Thus, millions of dif- ferent species of birds fly over these countries. Stopovers of migratory birds are located in wetlands in Egypt, Jordan/Israel, Saudi Arabia, Oman, UAE, Iraq and Iran [32,33]. Moreover, feral birds like pigeons, doves, ibis, sparrows and crows are frequent and widespread in these countries, which may come in ...
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... assess the relatedness of H9N2 viruses in the ME and NA, a phylogenetic tree based on HA gene sequences (n = 760) retrieved from GenBank and GISAID in March 2017 (Fig. 2, Supplementary Fig. S1 and 2000-2003, which share an ancestor with viruses from KSA in 1998. Interestingly, this virus probably transmitted back to quail in KSA in 2006, or the ancestor virus circulated unnoticed in parallel in KSA. ...
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Since November 2008, we have conducted active avian influenza surveillance in Bangladesh. Clades 2.2.2, 2.3.4.2, and 2.3.2.1a of highly pathogenic avian influenza H5N1 viruses have all been identified in Bangladeshi live poultry markets (LPMs), although, since the end of 2014, H5N1 viruses have been exclusively from clade 2.3.2.1a. In June 2015, a...
We conducted a 3-year longitudinal serologic survey on an open cohort of poultry workers, swine workers, and general population controls to assess avian influenza A virus (AIV) seroprevalence and seroincidence and virologic diversity at live poultry markets (LPMs) in Wuxi City, Jiangsu Province, China. Of 964 poultry workers, 9 (0.93%) were seropos...
Microbial proteases are responsible for proteolytic cleavage activation of Influenza A Virus (H5N1 and H9N2) hemagglutinin (HA). We examined the proteolytic activities of some pathogenic bacterial isolates such as Staphylococcus aureus, Pseudomonas aeruginosa and Mycoplasma gallisepticum. The contribution of endogenous and microbial proteases (exog...
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... 78 The low-pathogenic avian influenza virus H9N2 is more common than highly pathogenic strains and often causes mild or no symptoms in birds and poultry. 38 where mortality rates surged to as high as 65% in particular poultry and broiler farms. 85,86 Iran occupies a position on two major migration flyways: Central ...
The World Organization for Animal Health defines Avian Influenza Virus as a highly infectious disease caused by diverse subtypes that continue to evolve rapidly, impacting poultry species, pet birds, wild birds, non-human mammals, and occasionally humans. The effects of Avian influenza viruses have been recognised as a precursor for serious health concerns among affected birds, poultry, and human populations in the Middle East. Furthermore, low and high pathogenic avian influenza viruses lead to respiratory illness with varying severity, depending on the virus subtype (e.g., H5, H7, H9, etc.). Possible future outbreaks and endemics of newly emerging subtypes are expected to occur, as many studies have reported the emergence of novel mutations and viral subtypes. However, proper surveillance programs and biosecurity applications should be developed, and countries with incapacitated defences against such outbreaks should be encouraged to undergo complete reinstation and reinforcement in their health and research sectors. Public education regarding biosafety and virus prevention is necessary to ensure minimal spread of avian influenza endemic.
... The NS protein was found to have S at amino acid position 42 and A at position 149, both of which are virulence markers ( Table 3). The NP protein was found to have Q at (H5N2) between the Egyptian H5N8 and H9N2 viruses has been reported [31,32]. Furthermore, the zoonotic potential of H9N2 viruses has already been established, with at least 72 verified cases in humans [16]. ...
H9N2 avian influenza viruses (AIVs) affect both poultry and humans on a global level, and they are especially prevalent in Egypt. In this study, we sequenced the entire genome of AIV H9N2 isolated from chickens in Egypt in 2021, using next-generation sequencing (NGS) technology. Phylogenetic analysis of the resulting sequences showed that the studied strain was generally monophyletic and grouped within the G1 sublineage of the Eurasian lineage. Four segments (polymerase basic 2 [PB2], polymerase basic 1 [PB1], polymerase acidic [PA], and non-structural [NS]) were related to Egyptian genotype II, while the nucleoprotein (NP), neuraminidase (NA), matrix (M), and haemagglutinin (HA) segments were related to Egyptian genotype I. Molecular analysis revealed that HA protein contained amino acid residues (191H and 234L) that suggested a predilection for attaching to human-like receptors. The antigenic sites of HA had two nonsynonymous mutations: V194I at antigenic site A and M40K at antigenic site B. Furthermore, the R403W and S372A mutations, which have been observed in H3N2 and H2N2 strains that caused human pandemics, were found in the NA protein of the detected strain. The internal proteins contained virulence markers: 504V in the PB2 protein, 622G, 436Y, 207K, and 677T in the PB1 protein, 127V, 550L, and 672L in PA protein, and 64F and 69P in the M protein. These results show that the detected strain had undergone intrasubtype reassortment. Furthermore, it contains changes in the viral proteins that make it more likely to be virulent, raising a question about the tendency of AIV H9N2 to become highly pathogenic in the future for both poultry and humans.
... In Africa, H9N2 virus was first reported in Egypt and Tunisia in 2011, marking the beginning of its detection in Northern Africa (Tombari et al. 2011;El-Zoghby et al. 2012;Monne et al. 2013). Subsequently, since its emergence in Morocco in 2016, the virus has rapidly disseminated across the country and to other regions in Africa (El Houadfi et al. 2016;Nagy, Mettenleiter, and Abdelwhab 2017). In Western Africa, the virus was initially detected in 2017 in Burkina Faso (Zecchin et al. 2017), followed by subsequent identification in Senegal (Jallow et al. 2020), Ghana (Awuni et al. 2019;Kotey et al. 2022), Nigeria (Sulaiman et al. 2021), Benin, andTogo (Fusade-Boyer et al. 2021). ...
Avian influenza viruses (AIV) of the H9N2 subtype have become widespread in Western Africa since their first detection in 2017 in Burkina Faso. However, the genetic characteristics and diffusion patterns of the H9N2 virus remain poorly understood in Western Africa, mainly due to limited surveillance activities. In addition, Mali, a country considered to play an important role in the epidemiology of avian influenza viruses in the region, lacks more comprehensive data on the genetic characteristics of these viruses, especially H9N2 subtype. To better understand the genetic characteristics and spatiotemporal dynamics of H9N2 virus within this region, we carried out a comprehensive genetic characterization of H9N2 viruses collected through active surveillance in live bird markets in Mali between 2021 and 2022. We also performed a continuous phylogeographic analysis to unravel the dispersal history of H9N2 lineages between Northern and Western Africa. The identified Malian H9N2 virus belonged to the G1 lineage, similar to viruses circulating in both Western and Northern Africa, and possessed multiple molecular markers associated with an increased potential for zoonotic transmission and virulence. Notably, some Malian strains carried the RSNR motif at their cleavage site, mainly observed in H9N2 strains in Asia. Our continuous phylogeographic analysis revealed a single and significant long-distance lineage dispersal event of the H9N2 virus to Western Africa, likely to have originated from Morocco in 2015, shaping the westward diffusion of the H9N2 virus. Our study highlights the need for long-term surveillance of H9N2 viruses in poultry populations in Western Africa, which is crucial for a better understanding of virus evolution and effective management against potential zoonotic AIV strain emergence.
... Some studies suggest that this virus may have the potential to cause a more severe illness in humans [2,3]. In addition, infection with H9N2 has caused significant economic losses for the poultry industry [4]. Therefore, the prevention of the H9N2 influenza virus is an important strategy to control potential future epidemics or pandemics. ...
H9N2 avian influenza poses a significant public health risk, necessitating effective vaccines for mass immunization. Oral inactivated vaccines offer advantages like the ease of administration, but their efficacy often requires enhancement through mucosal adjuvants. In a previous study, we established a novel complex of polysaccharide from Atractylodes macrocephala Koidz binding with zinc oxide nanoparticles (AMP-ZnONPs) and preliminarily demonstrated its immune-enhancing function. This work aimed to evaluate the efficacy of AMP-ZnONPs as adjuvants in an oral H9N2-inactivated vaccine and the vaccine’s impact on intestinal mucosal immunity. In this study, mice were orally vaccinated on days 0 and 14 after adapting to the environment. AMP-ZnONPs significantly improved HI titers, the levels of specific IgG, IgG1 and IgG2a in serum and sIgA in intestinal lavage fluid; increased the number of B-1 and B-2 cells and dendritic cell populations; and enhanced the mRNA expression of intestinal homing factors and immune-related cytokines. Interestingly, AMP-ZnONPs were more likely to affect B-1 cells than B-2 cells. AMP-ZnONPs showed mucosal immune enhancement that was comparable to positive control (cholera toxin, CT), but not to the side effect of weight loss caused by CT. Compared to the whole-inactivated H9N2 virus (WIV) group, the WIV + AMP-ZnONP and WIV + CT groups exhibited opposite shifts in gut microbial abundance. AMP-ZnONPs serve as an effective and safe mucosal adjuvant for oral WIV, improving cellular, humoral and mucosal immunity and microbiota in the gastrointestinal tract, avoiding the related undesired effects of CT.
... On the contrary, the H9 bat IAVs turned out to be phylogenetically close to avian viruses (5,6). Mortality cases in humans caused by H5, H7, and H10 IAV subtypes containing H9N2 segments in their genome were registered in Asia (15). The H9 subtype is known for its broad host range, including birds, mammals, and humans, and it is well-established that reassortment between isolates from different host species can generate viruses with pandemic potential (16). ...
Influenza A viruses are important pathogens that can cause diseases with high mortality in humans, animals, and birds; and wild birds are considered the primary reservoir of all subtypes in nature. After discovering the H9 influenza A viruses in bats, questions arose about their potential to serve as an additional natural reservoir and about the priority of the viral origin: Did the virus initially circulate in bats and then transmit to birds or vice versa? Influenza A viruses of the H9 subtype are of particular interest because fatal infections of humans caused by H5, H7, and H10 influenza viruses contained RNA segments from H9 viruses. Recently, a novel subtype of influenza A virus (H19) was reported and it was closely related to the H9 bat influenza A virus by its hemagglutinin structure. The genome of novel H19 has revealed a mixed characteristic genomic signature of both avian and bat influenza viruses. The time to most recent common ancestor (TMRCA) estimates have shown that the divergence time between the bat and avian H9-similar influenza virus occurred approximately at the end of the XVIII century. This article discusses the evolution and possible origin of influenza viruses of the H9 subtype isolated from bats and birds. The obtained data, along with the known data, suggest that the primary reservoir of the H9 influenza virus is wild birds, from which the virus was transmitted to bats. We hypothesize that the novel H19 could be a descendant of an intermediate influenza virus that was in the transition stage of spillover from avian to bat hosts.
... On the other hand, several studies on LPAIV H9N2 in gamebirds have confirmed the susceptibility of these species to the virus [26,27], contrary to its pathogenicity, which is not fully substantiated, notably in quails and pheasants [13]. In fact, some reports indicate an asymptomatic carriage [13,27,28] both in field and experimental settings, while others describe symptomatic infection with respiratory clinical signs and a drop in egg production of up to 30% specifically in quails [13,[29][30][31]. Owing to their important epidemiological role as intermediate hosts in avian influenza virus transmission and adaptation to mammals, these species have been the focus of extensive studies on AIV replication [32]. ...
We report in this paper the first detection of low pathogenic avian influenza (LPAI) subtype H9N2 in houbara bustards and in gamebirds in Morocco. Starting in 2019, an increase in mortality rates related to respiratory distress was recorded in these species. Necropsy of the specimens revealed fibrinous sinusitis and tracheitis with intra-bronchial fibrin casts, which are consistent with H9N2 infection in chickens; therefore, implication of the virus in these outbreaks was strongly suspected. Consequently, between January 2020 and June 2023, birds with respiratory signs were necropsied for pathological lesions, tissue samples were examined by histopathology, and samples of trachea, lungs, and cecal tonsils were analyzed using quantitative real-time PCR for the detection of H9N2 virus. In addition, the sequencing of isolates was performed and lastly differential diagnosis with other respiratory pathogens was carried out. During the study period, 93 samples were collected from suspected H9N2 outbreaks, of which 30 tested positive for H9N2 virus: 23 Houbara bustards, 4 partridges, 2 quails, and 1 pheasant. Moreover, sequencing of the HA gene of the virus showed 97.33% nucleotide identity with strains reported previously in broilers in Morocco in 2017 and in 2022. Phylogenetic analysis grouped the Moroccan partridge isolates in the same cluster as viruses isolated in Morocco between 2016 and 2022, Algeria (2017), Burkina Faso (2017), Nigeria (2019), and Togo (2020). Additionally, 10 house sparrows from the premises of these birds were examined for the presence of H9N2 virus, revealing a 30% positivity rate. In conclusion, LPAIV H9N2 is circulating in houbara bustards and gamebirds in Morocco, and house sparrows might be a possible source of the infection. To our knowledge, this is the first report of LPAI H9N2 in the African species of houbara bustards worldwide and in gamebirds in Morocco.
... By the early 1990s, the first cases of H9N2 influenza viruses were detected in poultry in China co-circulating with H5N1 [4,7]. Since then, it has become widespread in domestic chickens in numerous countries across Asia, the Middle East, and West and North Africa, where the virus has become endemic in poultry populations [8][9][10][11]. Meanwhile, virus circulation is the least limited in European countries in domestic as well as wild bird populations, as compared to highly pathogenic influenza (HPAI H5Nx), for which cases continue to be reported particularly in gull species [12] The emergence of H9N2 viruses in Africa dates back to the early 2000s, with the first reported cases in Libya [13], followed by Egypt in 2006 [14] and Tunisia in 2009 [15]. In early 2016, the low pathogenic avian influenza (LPAI) H9N2 virus was identified in Morocco, resulting in significant economic losses for the poultry industry [16]. ...
... Therefore, in the context of endemic LPAIV H9N2 in several African countries, especially in the neighboring North Africa region, it is essential to extend vaccination programs to cover the entirety of poultry production. This approach of vaccination in breeders, layers, and turkey breeders has been launched in Algeria, Tunisia, and Egypt but is less extended in broilers [10,17,46]. Thus, updating vaccine strains based on ongoing surveillance surveys and circulating genotypes is a crucial factor for the epidemiological control of virus spreading and for limiting H9N2 circulation. ...
Avian influenza viruses pose significant threats to both the poultry industry and public health worldwide. Among them, the H9N2 subtype has gained substantial attention due to its high prevalence, especially in Asia, the Middle East, and Africa; its ability to reassort with other influenza viruses; and its potential to infect humans. This study presents a comprehensive phylogenetic and molecular analysis of H9N2 avian influenza viruses circulating in Morocco from 2021 to 2023. Through an active epidemiological survey, a total of 1140 samples (trachea and lungs) and oropharyngeal swabs pooled into 283 pools, collected from 205 farms located in 7 regions of Morocco known for having a high density of poultry farms, were analyzed. Various poultry farms were investigated (159 broiler farms, 24 layer farms, 10 breeder farms, and 12 turkey breeder farms). A total of 21 AI H9N2 strains were isolated, and in order to understand the molecular evolution of the H9N2 avian influenza virus, their genetic sequences were determined using the Sanger sequencing technique. Phylogenetic analysis was performed using a dataset comprising global H9N2 sequences to determine the genetic relatedness and evolutionary dynamics of the Moroccan strains. The results revealed the continued circulation and diversification of H9N2 avian influenza viruses in Morocco during the study period. Real-time RT-PCR showed a positivity rate of 35.6% (73/205), with cycle threshold values ranging from 19.2 to 34.9. The phylogenetic analysis indicated that all Moroccan strains belonged to a G1-like lineage and regrouped into two distinct clusters. Our newly detected isolates aggregated distinctly from the genotypes previously isolated in Morocco, North and West Africa, and the Middle East. This indicats the potential of virus evolution resulting from both national circulation and cross-border transmission. A high genetic diversity at both nucleotide and amino-acid levels was observed among all the strains isolated in this study, as compared to H9N2 strains isolated in Morocco since 2016, which suggests the co-circulation of genetically diverse H9N2 variants. Newly discovered mutations were detected in hemagglutinin positions 226, 227, and 193 (H3 numbering), which highlights the genetic evolution of the H9N2 AIVs. These findings contribute to our understanding of the evolution and epidemiology of H9N2 in the region and provide valuable insights for the development of effective prevention and control strategies against this emerging avian influenza subtype.
... 6 Documented cases of H9N2 infection in humans and evidence of such infection from serological research have primarily come from countries in the Middle East and North Africa. [6][7][8][9] According to the World Health Organization, more than 100 cases of human infection with H9N2 were reported as of July 2022, including more than 50 cases after 2020, 10 indicating that H9N2 viruses pose an increasing threat to public health in recent years. ...
H9N2 influenza viruses are globally endemic in birds, and a sharp increase in human infections with H9N2 occurred during 2021 to 2022. In this study, we assess the antigenic and pathogenic impact of 23 hemagglutinin (HA) amino acid mutations. Our study reveals that three specific mutations, labeled R164Q, N166D, and I220T, are responsible for the binding of antibodies with escape mutations. Variants containing R164Q and I220T mutations increase viral replication in avian and mammalian cells. Furthermore, T150A and I220T mutations are found to enhance viral replication in mice, indicating that these mutations may have the potential to adapt mammals. Structure analysis reveals that residues 164 and 220 bearing R164Q and I220T mutations increase interactions with the surrounding residues. Our findings enrich current knowledge about the risk assessment regarding which predominant HA immune-escape mutations of H9N2 viruses may pose the greatest threat to the emergence of pandemics in birds and humans.
... Both H5N1 and H9N2 were reported in Saudi Arabia [19,20] and raised significant concerns due to their zoonotic potential and potential for human-to-human transmission. Veterinarians working with poultry and in high-risk areas, where AI is prevalent in birds, face an elevated risk of exposure to AIV viruses due to their close contact with infected birds. ...
Veterinarians and other professionals who interact with animals on a daily basis encounter an elevated risk of exposure to both known and as-yet-undiscovered microbial agents. Additionally, they are also exposed to physical, chemical, and environmental hazards. Enhancing occupational health and safety in this context carries significant global significance.
This study aimed to comprehensively identify and outline the various biological, physical, chemical, and environmental health threats that were encountered by veterinarians in Saudi Arabia. To achieve this, we designed a self-completed questionnaire for 529 participants. The survey encompassed potential occupational hazards such as microbial diseases, injuries resulting from animal bites and scratches, allergies, and environmental risks like sunstroke and dust storms.
Among the 529 participating veterinarians, 45.9% (243 individuals) reported instances of zoonotic diseases
within the past five years. Notably, potential viral agents included Middle East respiratory syndrome coronavirus, avian influenza, and foot-and-mouth disease virus. Bacterial diseases were also frequently documented, with brucellosis (18.7%) and salmonellosis (7.9%) being notable pathogens. Protozoal infections were led by Leishmaniosis, constituting the most commonly detected protozoa (29 /529, 5.5%). Interestingly, 345 (65.2%) of the individuals reported that they have experienced animal bites and scratches. Needle stick injuries were also a common occupational hazard, with an incidence rate of 19.1%. Additionally, chemical exposure was prevalent, particularly to disinfectants (57.5%) and veterinary drugs (23.4%). The study participants also reported their exposure to various environmental hazards, including sunstroke, dust, sandstorms, and heavy rains.
The findings of this study draw attention to a concerning trend among veterinarians in Saudi Arabia. Their personal health and safety appear to receive inadequate attention, potentially heightening the risk of occupationally related health hazards. These outcomes highlight the need for a reevaluation of safety
protocols and infection control practices within the veterinary profession. The implications of this study can potentially inform the development of policies and initiatives aimed at mitigating occupationally related health hazards among veterinarians in Saudi Arabia.
... Single-Stranded RNA virus belonging to the family Orthomyxoviridae and genus (type) Influenzavirus A, and its genome consists of 8 segments. (1). According to the antigenic composition of surface glycoproteins among 18 types of hemagglutinin (HA) and 11 types of neuraminidase (NA), AIVs are classified into various subtypes (2). ...
... HA glycoprotein, as the main antigenic component, is the instrument of the virus for attachment to the sialic acid receptor of the host cell and fusion with its plasma membrane (1,2). Most AIVs bind more closely to sialic acid α2,3 in birds' respiratory and digestive systems. ...
... Most AIVs bind more closely to sialic acid α2,3 in birds' respiratory and digestive systems. A few mutations can increase the compatibility of the virus with mammalian α2-6 sialic acid, including human receptors, and this changes the host preference of the virus and causes efficient replication of the virus in the new host (1,6). Influenza viruses are prone to viral polymerase errors and the exchange of gene parts between different viruses infecting the same host. ...
Influenza is a significant poultry disease that can also affect humans, making it a zoonosis. The World Health Organization (WHO) and Contagious Diseases Organization (CDO) have increasingly focused on this disease in recent years. The isolation of influenza, particularly H5N1 and H9N2 subtypes, has dramatically increased, posing a global epidemic threat and causing deaths in various communities, as well as substantial losses in poultry. In response, using inactivated avian influenza vaccines has become common in controlling the disease. A comprehensive study was conducted in broiler farms in Iran to address the importance of influenza control through vaccination. The study involved 50,000 broiler chicks divided into seven groups with different vaccination programs. The groups were vaccinated at different ages and received varying vaccine doses. Serum samples were collected weekly and analyzed for antibody titers using hemagglutination inhibition (HI). The results showed that the groups vaccinated after seven days of age had a more consistent immune response and higher antibody titers than those vaccinated at a younger age or with only one dose. Early vaccination before seven days of age did not effectively stimulate the desired antibody response or achieve expected titers for the H9N2 influenza virus. Therefore, vaccinating older chicks improved immunity and flock protection more effectively. This study highlights the importance of vaccination strategies in controlling influenza in broiler farms. It provides valuable insights into the optimal timing and dosage of vaccines to enhance the immune response and protect against the H9N2 subtype. Implementing appropriate vaccination programs can contribute to mitigating the impact of influenza on poultry and reducing the risk of transmission to humans, ultimately safeguarding both animal and public health.
