A G219A #hemagglutinin #substitution increases #pathogenicity and viral #replication of Eurasian avian-like #H1N1 swine #influenza viruses

Abstract

The Eurasian avian-like swine (EA) H1N1 virus has been widely prevalent in the Chinese swine population and has caused infections in human. However, knowledge regarding its pathogenic mechanisms remains limited. In this study, we analyzed the pathogenic determinants of two G4 genotype EA H1N1 viruses (A/Swine/Guangdong/SS12/2017 and A/Swine/Jiangxi/1110/2017) with differing pathogenicity by constructing a series of reassortant and mutant viruses. The HA-G219A mutation was found to be determinant of pathogenicity in mice. Subsequent analyses revealed that this mutation enhances viral replication in human cells, improves thermal stability, reduces HA activation pH, and alters receptor-binding properties. Furthermore, HA-G219A mutation may be an adaptive mutation that facilitates influenza virus adaptation to swine, with its prevalence increasing in the swine population. This mutation may support cross-species transmission of EA H1N1 swine influenza viruses or genetic exchange with other virus subtypes/genotypes, potentially contributing to the emergence of pandemic viruses. These findings improve our understanding of EA H1N1 pathogenicity and highlight the critical need for ongoing surveillance of influenza viruses in pigs.

Source: Veterinary Microbiology, https://www.sciencedirect.com/science/article/abs/pii/S0378113525002007?via%3Dihub

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Highly Pathogenic Avian #Influenza A(#H5N1) Caused Mass Death among Black-legged #Kittiwakes (Rissa tridactyla) in #Norway, 2023

Abstract

In 2023, highly pathogenic avian influenza (HPAI) heavily affected gulls in Europe. In July, a mass mortality event was reported in the Black-legged Kittiwake (Rissa tridactyla) breeding colony at Ekkerøy in Northern Norway. The cause was confirmed to be infection with the HPAI H5N1 clade 2.3.4.4b virus, genotype EA-2022-BB. We describe the outbreak in Kittiwakes, including pathological and virological investigations, and discuss the management and zoonotic potential. With more than 15,000 dead birds reported, we estimate that the outbreak caused a reduction in the Kittiwake population at Ekkerøy of at least 50%. Diseased birds exhibited neurological signs. Necropsy of ten birds revealed a peracute fatal systemic disease, with severe lesions in the brain and pancreas co-localizing with the presence of viral RNA and antigen. Vascular expression of α2,3-linked sialic acids and viral RNA/antigen may reflect hematogenous virus spread. Further studies should investigate the long-term impact of HPAI on Kittiwake populations.

Source: BioRxIV, https://www.biorxiv.org/content/10.1101/2025.05.23.655725v1

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#Epidemiology and Genetic Characterization of Distinct #Ebola #Sudan #Outbreaks in #Uganda

Abstract

Background. 

Sudan virus (SUDV) has caused multiple outbreaks in Uganda over the past two decades, leading to significant morbidity and mortality. The recent outbreaks in 2022 and 2025 highlight the ongoing threat posed by SUDV and the challenges in its containment. This study aims to characterize the epidemiological patterns and phylogenomic evolution of SUDV outbreaks in Uganda, identifying key factors influencing transmission and disease severity. 

Methods. 

We conducted a retrospective observational study analyzing epidemiological and genomic data from SUDV outbreaks in Uganda between 2000 and 2025. Epidemiological data were collected from official sources, including the Ugandan Ministry of Health and the World Health Organization, supplemented with reports from public health organizations. Genomic sequences of SUDV were analyzed to investigate viral evolution and identify genetic variations associated with pathogenicity and transmissibility. 

Results. 

The 2022 outbreak involved 164 confirmed cases and a case fatality rate (CFR) of 33.5%, with significant geographic variation in case distribution. The 2025 outbreak, still ongoing, was first detected in Kampala, with evidence of both nosocomial and community transmission. Phylogenomic analysis revealed the presence of two main genetic groups, representing Sudan and Uganda, respectively. The genetic variability of the Ugandan cluster is higher than that observed in Sudan, suggesting a greater expansion potential, which aligns with the current outbreak. Epidemiological findings indicate that human mobility, weaknesses in the health system, and delays in detection contribute to the amplification of the outbreak. 

Conclusions. 

Our findings underscore the importance of integrated genomic and epidemiological surveillance in understanding SUDV transmission dynamics. The recurrent emergence of SUDV highlights the need for improved outbreak preparedness, rapid response mechanisms, and international collaboration. Strengthening real-time surveillance and enhancing healthcare system resilience are critical to mitigating the impact of future outbreaks.

Source: Infectious Disease Reports, https://www.mdpi.com/2036-7449/17/3/44

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#USA, Monitoring for Avian #Influenza A(#H5) Virus In #Wastewater (CDC, May 23 '25)

{Excerpt}

Time Period: May 11, 2025 - May 17, 2025

-- H5 Detection: 18 sites (4.5%)

-- No Detection: 381 sites (95.5%)

-- No samples in last week: 59 sites

(...)

Source: US Centers for Disease Control and Prevention, https://www.cdc.gov/bird-flu/h5-monitoring/index.html

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#Evolution, spread and #impact of highly pathogenic #H5 avian #influenza A viruses

Abstract

Since their first detection in 1996, highly pathogenic avian influenza viruses with H5 haemagglutinin of the A/Goose/Guangdong/1/1996 (Gs/Gd) lineage have caused outbreaks in domestic and wild animals associated with mass morbidity and mortality, and economic losses as well as sporadic human infections. These viruses have spread to hosts across the European, Asian, African, and North and South American continents, and most recently Antarctica, representing a major threat to wildlife, domestic animals and humans. Owing to continuous circulation in poultry, Gs/Gd lineage viruses have diversified into numerous distinct genetic and antigenic (sub)clades, and genetic diversity has further increased by extensive reassortment with low pathogenic avian influenza viruses of wild birds. In this Review, we discuss the historical emergence of Gs/Gd lineage viruses and their evolution and geographical spread. An overview of the major determinants of host range and cross-species transmission is provided to summarize phenotypic changes that may signal increased zoonotic or pandemic risks. The recent unusual outbreaks in wild carnivorous mammals and dairy cows is discussed, as well as the changing risk to humans. Countermeasures and mitigation strategies are described from the One Health perspective for future (pre-)pandemic preparedness.

Source: Nature Reviews Microbiology, https://www.nature.com/articles/s41579-025-01189-4

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Comparative #pathogenicity of three A(#H5N1) clade 2.3.4.4b HPAI viruses in blue-winged #teal and #transmission to domestic #poultry

ABSTRACT

Long-distance migratory ducks play a critical role in the maintenance and dissemination of A(H5N1) viruses. Comparative pathogenicity studies were conducted on blue-winged teal (BWTE; Anas discors) using three distinct genotypes of A(H5N1) clade 2.3.4.4b viruses (A1, B1.3, and B4.1) isolated from wild ducks in Canada. Twenty-four hours post-intranasal infection of BWTE, contact turkeys and chickens were introduced into each of the groups to evaluate viral transmission. The levels of viral shedding in BWTE increased from 3 to 7 days post-infection (dpi) and continued at lower levels until 14 dpi. The A1 genotype virus (MALL/NS/22) was found to be the least pathogenic to BWTE compared to the reassortant genotypes, B4.1 (RBME/BC/22) and B1.3 (BWTE/MB/22). The B1.3 genotype was the most virulent to BWTE and caused 66.7% mortality compared to 12.5% mortality caused by the B4.1 genotype. The extent of transmission from infected BWTE to contact turkeys and chickens showed variations. Turkeys housed with BWTE infected with either virus died within 6 to 10 days post-contact (dpc). Conversely, the transmission and mortality among contact chickens varied. The highest mortality (3 out of 5) occurred in chickens exposed to BWTE infected with the B1.3 genotype. Whilst in the B4.1 genotype, 2 out of 6 chickens died, none of the chickens in the A1 genotype succumbed to infection. No shedding or seroconversion was noted in all surviving chickens. This research underscores variations in the pathogenic traits and transmissibility among the different genotypes of A(H5N1) clade 2.3.4.4b viruses. This finding is vital for understanding the role of migratory birds in the epidemiology of A(H5N1) and the need for continuous monitoring of these viruses.

Source: mSphere, https://journals.asm.org/doi/10.1128/msphere.00021-25

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Emergence of #Oropouche Virus in Espírito Santo State, #Brazil, 2024

Abstract

Oropouche virus (OROV), historically endemic to the Amazon, had spread to nearly all Brazil states by 2024; Espírito Santo emerged as a transmission hotspot in the Atlantic Forest biome. We characterized the epidemiologic factors driving OROV spread in nonendemic southeast Brazil, analyzing environmental and agricultural conditions contributing to viral transmission. We tested samples from 29,080 suspected arbovirus-infected patients quantitative reverse transcription PCR for OROV and dengue, chikungunya, Zika, and Mayaro viruses. During March‒June 2024, the state had 339 confirmed OROV cases, demonstrating successful local transmission. Spatial analysis revealed that most cases clustered in municipalities with tropical climates and intensive cacao, robusta coffee, coconut, and pepper cultivation. Phylogenetic analysis identified the Espírito Santo OROV strains as part of the 2022–2024 Amazon lineage. The rapid spread of OROV outside the Amazon highlights its adaptive potential and public health threat, emphasizing the need for enhanced surveillance and targeted control measures.

Source: US Centers for Disease Control and Prevention, https://wwwnc.cdc.gov/eid/article/31/6/24-1946_article

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Effect of #JYNNEOS #vaccination on #mpox clinical #progression: a case–control study

Summary

Background

The JYNNEOS modified vaccinia virus Ankara vaccine is effective in preventing clade IIb mpox disease. However, vaccine effects on mpox severity are poorly understood. We aimed to assess associations between reported clinical characteristics and vaccination status among individuals with laboratory-confirmed mpox.

Methods

We conducted a case–control study using data collected from public health surveillance interviews of people with mpox in California. Eligible participants for primary analyses were men who were cisgender and participated in telephone interviews with complete responses recorded about anatomical sites where they had lesions. We estimated JYNNEOS vaccine effectiveness against progression to disease involving disseminated lesions via the adjusted odds ratio of vaccination, comparing participants who reported lesions disseminated across multiple anatomical regions (cases) with participants who reported lesions contained to a single anatomical region (controls). We used the same case–control framework to estimate vaccine effectiveness against progression to hospitalisation and prodromal symptoms.

Findings

Men who were cisgender represented 5763 (94·3%) of 6112 people reported to have laboratory-confrimed mpox in California from May 12, 2022, to Dec 31, 2023, among whom, 4609 (79·9%) met eligibility criteria and were included in primary analyses. Of 4609 participants, 1566 (34·0%) were classified as controls and 3043 (66·0%) were classified as cases. Among 3043 cases, 114 (3·7%) received pre-exposure vaccination and 214 (7·0%) received post-exposure vaccination only. Among 1566 controls, 285 (18·2%) received pre-exposure vaccination and 146 (9·3%) received post-exposure vaccination only. For pre-exposure vaccination, vaccine effectiveness against progression was 58·8% (95% CI 50·3–65·9); for post-exposure vaccination, vaccine effectiveness against progression was 15·9% (3·3–26·8). Pre-exposure vaccine effectiveness against progression was 66·6% (56·8–74·2) among people negative for HIV and 44·8% (27·5–58·0) for those with HIV. Pre-exposure vaccination was also associated with protection against progression to severe illness necessitating hospitalisation (85·4% [95% CI 54·3–95·3]), and with reduced odds for fever, chills, and lymphadenopathy.

Interpretation

Among men who were cisgender with mpox, pre-exposure vaccination with JYNNEOS was associated with less severe illness. Awareness of an attenuated disease phenotype involving localised lesions without accompanying prodromal symptoms is needed to ensure accurate diagnosis of mpox in previously vaccinated individuals.

Source: Lancet Infectious Diseases, https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(25)00180-X/fulltext?rss=yes

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Highly Pathogenic Avian #Influenza A(#H5N1) in Wild #Birds and a #Human, British Columbia, #Canada, 2024

Abstract

We characterized highly pathogenic avian influenza A(H5N1) clade 2.3.4.4b genotype D1.1 in wild birds and a human in British Columbia, Canada, during 2024. D1.1, the predominant genotype circulating in fall 2024, is a reassortment between Eurasian A3 lineage viruses, introduced to North America in 2022, and North American lineage viruses.

Source: US Centers for Disease Control and Prevention, https://wwwnc.cdc.gov/eid/article/31/6/24-1862_article

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#Brazil, Ministry of #Health rules out case of {#H5N1} #birdflu virus infection in a #worker from Rio Grande do Sul

The Ministry of Health reports that a suspected case of Avian Influenza has been ruled out in a worker at a farm in the municipality of Montenegro (RS), where an outbreak of the disease was identified in birds. 

On the afternoon of Tuesday (20/05), Fiocruz, the reference laboratory for this type of analysis, confirmed that the test for the disease was negative. At this time, there are no other suspected or under investigation cases in Brazil.

The Ministry of Health, together with the State Health Department of Rio Grande do Sul, is monitoring all people who may have been exposed to the virus through direct contact with infected birds to monitor their health status, start treatment immediately at the first symptoms and preventative surveillance of possible contacts. 

There are no records of transmission of the disease from one person to another worldwide.

The risk of human infection is low and does not occur through the consumption of meat or eggs, but rather through direct contact with sick birds or contaminated environments. Therefore, the most effective preventive measure is to avoid contact with dead or sick birds.

The Ministry of Health is working with the Ministry of Agriculture and Livestock (Mapa) and the State Health Department of Rio Grande do Sul to provide all necessary support for actions related to the first case of bird flu on a commercial farm in the municipality of Montenegro (RS). 

To ensure a rapid response to possible outbreaks, the Ministry of Health launched, in December 2024, the National Contingency Plan for the Health Sector for Avian Influenza, which guides the ministry's actions, including integrated surveillance, laboratory diagnosis, assistance and health communication. 

In this sense, Brazil is working on different fronts to prepare for a possible risk of cases in humans. The Ministry of Health, through the SUS , has the capacity to perform laboratory tests, maintains a stock of the medicine to treat the different types of influenza (Oseltamivir) and, if necessary, has the technology to produce vaccines. 

Understand how the suspected case was ruled out

The investigation into the suspected case began on May 18, when the worker at the Montenegro (RS) farm, who was already being monitored by state surveillance and the Ministry of Health, showed the first symptoms. Treatment began immediately and the sample was sent to Fiocruz, in Rio de Janeiro.

The PCR test was initially performed, which identifies specific genetic material from the influenza virus – if positive, other tests are performed to identify the type of influenza, including avian flu. In the case in question, the initial test was negative for any type of influenza.

For those who work with wild animals, it is recommended to use Personal Protective Equipment (PPE) after identifying infected animals or those with symptoms suggestive of avian influenza, such as gloves, N95 mask or higher and eye protection, in addition to care such as hand hygiene, avoiding touching eyes, mouth and nose and changing clothes after contact with infected animals.

Ministry of Health 

Source: Ministry of Health, https://www.gov.br/saude/pt-br/assuntos/noticias/2025/maio/ministerio-da-saude-descarta-caso-de-gripe-aviaria-em-um-trabalhador-do-rio-grande-do-sul

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#Pathogenicity and #transmissibility of bovine-derived HPAI #H5N1 B3.13 virus in #pigs

Abstract

Since the first emergence of highly pathogenic avian influenza (HPAI) H5N1 viruses in dairy cattle, the virus has continued to spread, reaching at least 17 states and at least 950 dairy herds in the United States. Subsequently, spillovers of the virus from dairy cattle to humans have been reported. Pigs are an important reservoir in influenza ecology because they serve as a mixing vessel in which novel reassortant viruses with pandemic potential can be generated. Here, we show that oro-respiratory infection of pigs resulted in productive replication of a bovine-derived HPAI H5N1 B3.13 virus. Infectious virus was mainly identified in the lower respiratory tract of principal infected pigs, and sero-conversion was observed in most of the principal pigs at later time points, suggesting limited replication of the bovine-derived HPAI H5N1 B3.13 virus in pigs. In one animal, we detected the emergence of a mutation in hemagglutinin (HA) previously associated with increased affinity for “mammalian-type” α2,6-linked sialic acid receptors, but this mutation did not reach majority consensus levels. Sentinel contact pigs remained sero-negative throughout the study, indicating lack of transmission. These results support that pigs are susceptible to a bovine-derived HPAI H5N1 B3.13 virus, but this virus did not replicate as robustly in pigs as mink-derived HPAI H5N1 and swine-adapted influenza viruses.

Source: Emerging Microbes and Infections, https://www.tandfonline.com/doi/full/10.1080/22221751.2025.2509742

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#Bulgaria - High pathogenicity avian #influenza #H5N1 viruses (#poultry) (Inf. with) - Immediate notification

 

On the 19th of May, an official veterinary doctor was called to the farm due to suspected influenza, as there was an increase in mortality within the animals. On the same day, samples were taken and sent to the Bulgarian National Laboratory for Avian Influenza, where, on the 20th of May, it was confirmed that the farm was affected by a highly pathogenic avian influenza virus.

Source: WOAH, https://wahis.woah.org/#/in-review/6490

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A protective and broadly binding #antibody class engages the #influenza virus #hemagglutinin head at its stem interface

ABSTRACT

Influenza infection and vaccination impart strain-specific immunity that protects against neither seasonal antigenic variants nor the next pandemic. However, antibodies directed to conserved sites can confer broad protection. Here, we identify and characterize a class of human antibodies that engage a previously undescribed, conserved epitope on the influenza hemagglutinin (HA) protein. Prototype antibody S8V1-157 binds at the normally occluded interface between the HA head and stem. Antibodies to this HA head–stem interface epitope are non-neutralizing in vitro but protect against lethal influenza infection in mice. These antibodies bind to most influenza A subtypes and seasonal human variants, and are present at low frequencies in the memory B cell populations of multiple human donors. Vaccines designed to elicit these antibodies might contribute to “universal” influenza immunity.

IMPORTANCE

Antibodies to the influenza virus hemagglutinin (HA) protein confer the strongest protection against infection. Human antibodies elicited by infection and/or vaccination fail to protect against antigenically novel animal, pandemic, or human seasonal viruses. Improved vaccines are needed. We identify a novel class of antibodies that bind most divergent HA subtypes and all seasonal human HA antigenic variants tested. These antibodies confer protection from lethal influenza challenge in animal models. The corresponding epitope on the HA head is occluded by its interaction with the stem and is inaccessible in the well-resolved prefusion state. The immunogenicity of this head–stem interface indicates that poorly understood conformations of HA presenting widely conserved surfaces are explored in biochemical, cell-based, and in vivo assays. Head–stem interface antibodies warrant further investigation as an avenue to improve influenza vaccines and therapeutics.

Source: mBio, https://journals.asm.org/doi/10.1128/mbio.00892-25

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Characterization of emerging #H3N3 avian #influenza viruses in #poultry in #China

Abstract

Avian influenza viruses continue to challenge poultry and human health; therefore, careful surveillance and evaluation of emerging viruses are important for animal disease control and human influenza pandemic preparedness. In this study, we detected a series of H3N3 subtype avian influenza viruses in chickens, pigeons, and ducks during our routine surveillance and diagnosis between September 2022 and May 2023. We performed extensive analyses to fully understand the origins of these viruses and their risk to animals and humans. We found that the viruses were complex reassortants; the viruses from chickens and pigeons carry genes mainly derived from H3N8 viruses and H10N3 viruses, whereas the two duck viruses were reassortants of duck and wild bird viruses. The chicken and pigeon, but not duck, viruses replicated in multiple organs of chickens and were shed for up to 13 days, but none caused disease or death. Six of the viruses tested all bound to both avian- and human-type receptors. Seventeen viruses were tested in mice and most replicated efficiently but were not lethal. Six viruses were tested in guinea pigs, and four of them transmitted efficiently via respiratory droplets. Our study thus identified novel H3N3 avian influenza viruses and revealed their zoonotic potential, thereby emphasizing the importance of careful monitoring and control of H3 viruses in animals.

Source: Emerging Microbes and Infections, https://www.tandfonline.com/doi/full/10.1080/22221751.2025.2509748#

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Investigating Factors Driving Shifts in Subtype #Dominance within #H5Nx Clade 2.3.4.4b High-Pathogenicity Avian #Influenza viruses

Abstract

H5Nx clade 2.3.4.4b high-pathogenicity avian influenza viruses (HPAIVs) have decimated wild bird and poultry populations globally since the autumn of 2020. In the United Kingdom (UK) and in continental Europe, the H5N8 subtype predominated during the first epizootic wave of 2020/21, with few detections of H5N1. However, during the second (2021/22) and third (2022/23) epizootic waves, H5N1 was the dominant subtype. The rapid shift in dominance from H5N8 to H5N1 was likely driven by a combination of virological, immunological, and/or host-related factors. In this study, we compared viral fitness and immunological responses in ducks, a key reservoir species, using dominant genotypes of H5N1 (genotype AB) and H5N8 (genotype A) from the second wave. While viral shedding dynamics were similar for both viruses, H5N8 was more pathogenic. Antigenic analysis of post-infection duck sera revealed that the haemagglutinin (HA) protein was antigenically similar across clade 2.3.4.4b H5 HPAIVs, but neuraminidase (NA) proteins displayed different patterns of cross-reactivity. We also modelled a scenario where ducks were pre-exposed to H5N1 (genotype C) or H5N8 (genotype A) from the first wave and subsequently challenged with either homologous or heterologous subtypes from the second wave (genotype AB or A). Despite the absence of seroconversion, pre-exposure to different subtypes resulted in varying clinical outcomes following challenge. These findings indicate that both viral and immunological factors likely played significant roles in the emergence and spread of H5Nx HPAIVs in wild bird populations.

Source: BioRxIV, https://www.biorxiv.org/content/10.1101/2025.04.23.650244v2

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Long-Term Clinical #Outcomes of #Adults Hospitalized for #COVID19 #Pneumonia

Abstract

We conducted a multicenter, observational, 12-month follow-up study to identify the extended health burden of severe COVID-19 pneumonia by characterizing long-term sequelae of acute infection in participants previously enrolled in clinical trials for severe COVID-19 pneumonia requiring hospitalization. Overall, 134 (77.5%) of 173 participants completed the study. At 12 months, 51 (29.5%) participants reported cough, 60 (34.7%) reported dyspnea, 56 (32.4%) had residual lung texture abnormalities on high-resolution computed tomography scans, 26 (15.0%) had impaired forced vital capacity, 52 (30.1%) had cognitive impairment, and 77 (44.5%) reported fatigue. Disease severity during acute infection and age were associated with persistent lung abnormalities; history of hypertension was associated with higher prevalence of fatigue and more frequent dyspnea and cough; and age and obesity were associated with long-term cognitive impairment. Our findings underscore the long-term health burden of severe COVID-19 pneumonia, reinforcing the importance of regular monitoring in older persons and those with underlying illnesses.

Source: US Centers for Disease Control and Prevention, https://wwwnc.cdc.gov/eid/article/31/6/24-1097_article

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Progressive #Adaptation of Subtype #H6N1 Avian #Influenza Virus in #Taiwan Enhances #Mammalian #Infectivity, Pathogenicity, and #Transmissibility

Abstract

The interspecies transmission of avian influenza viruses remains a significant public health concern. H6 viruses have gained attention following the first human infection by a chicken-origin H6N1 virus (A/Taiwan/02/2013, Hu/13), highlighting their zoonotic potential. To understand the evolutionary trajectory and mammalian adaptation of this Taiwan lineage, we compared two avian isolates (A/Chicken/Taiwan/CF19/2009, Ck/09; A/Chicken/Taiwan/2267/2012, Ck/12) and Hu/13 in vitro and in vivo. Hu/13 exhibited enhanced replication in MDCK cells, producing larger plaques and higher viral titers than Ck/09 and Ck/12. In BALB/c mice, Hu/13 demonstrated the highest pathogenicity and mortality, followed by Ck/12, while Ck/09 induced minimal morbidity. Hu/13 and Ck/12 replicated efficiently in respiratory tissues, eliciting robust cytokine responses and severe pulmonary lesions. In ferrets, Hu/13 showed relatively efficient transmission, infecting all direct physical-contact and two out of three airborne-contact ferrets, whereas Ck/09 failed to transmit. Histopathology confirmed escalating lung pathology from Ck/09 to Ck/12 and Hu/13. Whole-genome sequencing identified adaptive mutations in Hu/13 during ferret replication, though no canonical mammalian-adaptive changes (e.g., PB2-E627K or HA-Q226L) were detected. These findings demonstrate progressive mammalian adaptation, replication efficiency, and transmissibility within the Taiwan H6N1 lineage. Enhanced surveillance is crucial to monitor mammalian-adaptive mutations, informing pandemic preparedness and public health strategies.

Source: Viruses, https://www.mdpi.com/1999-4915/17/5/733

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#Phylogenetic Analysis and Spread of HPAI #H5N1 in Middle Eastern Countries Based on #Hemagglutinin and #Neuraminidase Gene Sequences

Abstract

Highly pathogenic avian influenza (HPAI) A/H5N1 viruses threaten animal and human health worldwide. The first documented cases in the Middle East were reported in 2005; however, despite extensive phylogenetic studies, there is limited information on the transmission dynamics of the virus within this region. We analyzed HA and NA gene sequences from various hosts to address this gap and to understand the virus’s spread and evolution in the Middle East. We hypothesized that H5N1 transmission exhibits host-specific or geographically influenced clade structures in this region. This study traced transmission pathways of HPAI A/H5N1 through a phylogenetic and amino acid sequence analysis of HA and NA gene segments from isolates across different hosts in Middle Eastern countries, using the MUSCLE algorithm for alignments and MEGA11 software for phylogenetic analysis. Sequences were selected from NCBI’s virus database based on geographic and host diversity, including those from birds, humans, and other mammals, and were collected at different time points, predominantly after the early 2000s. An amino acid phylogenetic tree was also constructed to examine the conservation of key HA and NA protein residues, identifying distinct clades linked to specific countries and host species, suggesting a possible interspecies transmission and cross-border spread distinct between Egypt and neighboring countries. These findings underscore the role of migratory birds in regional transmission and point to the need for more targeted surveillance and biosecurity efforts, offering more genomic insights into the spread of HPAI A/H5N1 and contributing valuable information for future prevention strategies.

Source: Viruses, https://www.mdpi.com/1999-4915/17/5/734

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Avian #Influenza Virus #Infections in #Felines: A Systematic Review of Two Decades of Literature

Abstract

As an avian influenza virus (AIV) panzootic is underway, the threat of a human pandemic is emerging. Infections among mammalian species in frequent contact with humans should be closely monitored. One mammalian family, the Felidae, is of particular concern. Domestic cats are susceptible to AIV infection and provide a potential pathway for zoonotic spillover to humans. Here, we provide a systematic review of the scientific literature to describe the epidemiology and global distribution of AIV infections in felines reported from 2004 to 2024. We identified 607 AIV infections in felines, including 302 associated deaths, comprising 18 countries and 12 felid species. We observed a drastic flux in the number of AIV infections among domestic cats in 2023 and 2024, commensurate with the emergence of H5N1 clade 2.3.4.4b. We estimate that this phenomenon is underreported in the scientific literature and argue that increased surveillance among domestic cats is urgently needed.

Source: Open Forum Infectious Diseases, https://academic.oup.com/ofid/article/12/5/ofaf261/8123920

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Endemic #coronavirus #infection is associated with #SARS-CoV-2 Fc receptor-binding #antibodies

ABSTRACT

Recent documented infection with an endemic coronavirus (eCoV) is associated with less severe coronavirus disease 2019 (COVID-19), yet the immune mechanism behind this protection has not been fully explored. We measured both antibody and T-cell responses against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in SARS-CoV-2-naïve individuals, classified into two groups: those with or without presumed recent eCoV infections. There was no difference in neutralizing antibodies and T-cell responses against SARS-CoV-2 antigens between the two groups. SARS-CoV-2-naïve individuals with recent presumed eCoV infection, however, had higher and significantly correlated levels of Fc receptor (FcR)-binding antibodies against eCoV spikes (S) and SARS-CoV-2 S2. Recent eCoV infection boosts cross-reactive antibodies that can mediate Fc effector functions, and this may play a role in the observed heterotypic immune protection against severe COVID-19.

IMPORTANCE

With the recent emergence of SARS-CoV-2 and other pathogenic coronaviruses, it is important to understand how the immune system may protect against disease from future coronavirus outbreaks. We investigated the adaptive immune responses elicited from a “common cold” eCoV and measured the cross-reactivity against SARS-CoV-2 in individuals classified as having or not having a recent eCoV infection. Although both groups had similar cross-reactive T-cell and neutralizing antibody responses, individuals with a recent eCoV infection had higher antibody levels capable of Fc receptor binding. Antibodies with enhanced Fc receptor binding could mediate the killing of virally infected cells through mechanisms such as antibody-dependent cellular cytotoxicity, which may reduce the severity of COVID-19. Antibodies capable of mediating Fc effector functions may be critical for therapies and vaccines against future pathogenic coronavirus outbreaks.

Source: Journal of Virology, https://journals.asm.org/doi/full/10.1128/jvi.00550-25?af=R

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