#Detection of #Hemagglutinin #H5 #influenza A virus #RNA and model of potential inputs in an #urban #California #sewershed

Abstract

In 2024, the highly pathogenic avian influenza A H5N1 caused outbreaks in wild birds, poultry, cows, and other mammals in the United States with 61 human cases also reported by the CDC. Detection of influenza A H5 RNA in wastewater has been previously reported in sewersheds in Texas and North Carolina with nearby impacted dairy herds following the emergence of H5N1 in dairy cows. Here, we conduct retrospective testing of total influenza A and H5 hemagglutinin genes in wastewater as well presenting and applying new assays for detection of H1 and H3 genes across a respiratory virus season in an urban California sewershed from September 2023-May 2024. Total influenza A, H1, and H3 were regularly detected, while H5 was first detected in March. We developed a model that uses Monte Carlo simulations and previously published parameters to estimate numbers of infected people, poultry, wild birds, or liters of H5-contaminated milk required to result in measured H5 concentrations in wastewater. Our findings demonstrate that in this California sewershed, contaminated milk or infected poultry were the most likely sources of H5 to wastewater. We created a publicly available tool to apply the H5 input model in other sewersheds estimate required inputs.

Source: MedRxIV, https://www.medrxiv.org/content/10.1101/2024.12.31.24319823v1

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Acute #Encephalopathy Associated with #Human #Adenovirus Type 14 Infection in 7-Year-Old Girl, #Japan

Abstract

Only 2 cases of human adenovirus type 14 (HAdV-14) have been reported in Japan since 1980. We report a 7-year-old girl with acute encephalopathy associated with HAdV-14 infection genetically similar to strains from the United States. The patient had not had contact with international travelers. HAdV-14 surveillance should be strengthened in Japan.

Source: Emerging Infectious Diseases Journal, https://wwwnc.cdc.gov/eid/article/31/2/24-1168_article

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Two #genotypes of #H3N2 #swine #influenza viruses identified in #pigs from #Shandong Province, #China

 {Summary}

Swine influenza virus (SIV) is a highly contagious pathogen that poses significant economic challenges to the swine industry and carries zoonotic potential, underscoring the need for vigilant surveillance. In this study, we performed a comprehensive genetic and molecular analysis of H3N2 SIV isolates obtained from 372 swine samples collected in Shandong Province, China. Phylogenetic analysis revealed two distinct genotypes. The surface genes of both genotypes clustered with the human-like H3N2 lineage, while the internal genes of one genotype clustered with the 2009 pandemic H1N1 (pdm/09) lineage. In the second genotype, the NS gene clustered with the classical swine (CS) H1N1 lineage, while the remaining internal genes clustered with pdm/09, suggesting stable integration of pdm/09 gene segments into H3N2 SIV. Homology analysis showed over 96% genetic similarity between the isolates and reference strains from China and Brazil, suggesting potential transmission through swine trade or human movement. Molecular characterization identified amino acid substitutions in the HA protein (190D, 226I, and 228S), potentially enhancing the virus’s affinity for human-like receptors, thereby increasing the zoonotic risk. Key mutations in the PB2 (271A, 591R), PA (336M, 356R, 409N), and M2 (S31N) proteins, along with novel drug resistance mutations, indicate the potential for enhanced virulence and drug resistance in these isolates. Moreover, glycosylation site analysis revealed four differences, and antigenic site analysis showed 13 differences between the HA proteins of the isolates and the WHO-recommended vaccine strain A/Cambodia/E0826360/2020 for the 2021–2022 season, which may reduce vaccine efficacy. Serological analysis revealed that 11 out of the tested serum samples were positive for H3N2 antibodies, resulting in an overall positivity rate of 0.42%. These findings emphasize the urgent need for strengthened SIV surveillance in China to monitor the risk of human transmission and ensure better preparedness for future influenza outbreaks.

Source: Frontiers in Cellular and Infection Microbiology, https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2024.1517023/full

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#USA, #Wastewater #Data for Avian #Influenza A(#H5) (As of Dec. 28 '24)

 {Excerpt}

Time Period: December 22 - December 28, 2024

-- H5 Detection: 44 sites (18.6%)

-- No Detection: 192 sites (81.4%)

-- No samples in last week: 150 sites

(...)

Source: US Centers for Disease Control and Prevention, https://www.cdc.gov/nwss/rv/wwd-h5.html

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#USA, #Delaware Announces First Presumptive Positive #H5 Avian #Influenza Case Detected on Kent County {#Poultry} #Farm in 2025

{Excerpt}

DOVER, Del. (January 3, 2025) – The Delaware Department of Agriculture announced this morning that preliminary testing of a commercial broiler flock in Kent County, Del., has returned presumptive positive H5 from the University of Delaware’s Lasher Laboratory in Georgetown, part of the National Animal Health Laboratory Network. Additional samples have been sent to the U.S. Department of Agriculture’s National Veterinary Services Laboratory (NVSL) for further confirmation.

State officials have quarantined the affected premises, and the birds on the property are being depopulated to prevent the spread of the disease. Birds from the affected flock will not enter the food system.

Avian influenza is a highly contagious airborne respiratory virus that spreads quickly among birds through nasal and eye secretions and manure. The virus can be spread from flock to flock, including flocks of wild birds, through contact with infected poultry, equipment, and the clothing and shoes of caretakers. This virus affects poultry, like chickens, ducks, and turkeys, and some wild bird species, such as ducks, geese, shorebirds, and raptors.

Last week, Delaware announced presumptive positive H5 results in snow geese found at Prime Hook Beach. The state is still awaiting confirmatory results from NVSL. With the assistance of the public, more than 850 wild birds, a majority of them snow geese but including Canada geese, other waterfowl, vultures, and other birds, were reported dead via the DNREC Division of Fish and Wildlife’s Sick and Dead Wildlife Reporting Form. While some of these may be duplicate reports, or deaths due to other causes, officials know that more birds have succumbed to the virus, dying in places out of sight.

To better protect their flocks, poultry producers and backyard flock owners must realize that what occurs in wild birds does impact the health of their birds and that this is not only a problem along Delaware’s coast, which is where many of the reported dead birds have been located so far. In the evening hours, snow geese fly to water to roost, where they can then spread the virus in their flock. Those birds that are not sick or are strong enough to fly in the morning will then take flight, moving inland to open space, including farm fields, to forage. At this time that virus can be introduced to poultry farms and areas where backyard flocks are commingling with wildlife or are not under cover, protecting them from infected wild bird droppings. Snow geese are very mobile, flying as far into Maryland or New Jersey in a day.

Considering this new case and the prevalence of the virus in the wild bird population, all poultry owners need to increase their vigilance in protecting their flocks from contracting avian influenza by following these steps:

• Limit, monitor, and record any movement of people, vehicles, or animals on or off your farm.

• Permit only essential workers and vehicles to enter the farm to limit the chances of bringing the virus from an outside source.

• Avoid visiting other poultry farms and any unnecessary travel off the farm.

• Disinfect equipment, vehicles, footwear, and other items that come into contact with flocks.

• Keep your flock away from wild or migratory birds, especially waterfowl.

• Isolate any ill animals and contact your veterinarian.

(...)

Source: Government of Delaware, https://dhss.delaware.gov/dhss/

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#Germany - #Influenza A #H5N1 viruses of high pathogenicity (Inf. with) (non-poultry including wild birds) (2017-) - Immediate notification

Backyard reared non-poultry birds in Rheinland-Pfalz Region.

Source: WOAH, https://wahis.woah.org/#/in-review/6149

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Random forest #algorithm reveals novel sites in #HA #protein that shift #receptor binding preference of the #H9N2 avian #influenza virus

Abstract

A switch from avian-type α-2,3 to human-type α-2,6 receptors is an essential element for the initiation of a pandemic from an avian influenza virus. Some H9N2 viruses exhibit a preference for binding to human-type α-2,6 receptors. This identifies their potential threat to public health. However, our understanding of the molecular basis for the switch of receptor preference is still limited. In this study, we employed the random forest algorithm to identify the potentially key amino acid sites within hemagglutinin (HA), which are associated with the receptor binding ability of H9N2 avian influenza virus (AIV). Subsequently, these sites were further verified by receptor binding assays. A total of 12 substitutions in the HA protein (N158D, N158S, A160N, A160D, A160T, T163I, T163V, V190T, V190A, D193N, D193G, and N231D) were predicted to prefer binding to α-2,6 receptors. Except for the V190T substitution, the other substitutions were demonstrated to display an affinity for preferential binding to α-2,6 receptors by receptor binding assays. Especially, the A160T substitution caused a significant upregulation of immune-response genes and an increased mortality rate in mice. Our findings provide novel insights into understanding the genetic basis of receptor preference of the H9N2 AIV.

Source: Virologica Sinica, https://www.sciencedirect.com/science/article/pii/S1995820X24002116?via%3Dihub

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Highly Pathogenic Avian #Influenza (HPAI) #H5N1 virus in #Finland in 2021-2023 – Genetic diversity of the viruses and infection kinetics in #human dendritic cells

Abstract

Highly pathogenic avian influenza (HPAI) H5N1 is known for its virulence and zoonotic potential, infecting birds and mammals, thus raising public health concerns. Since 2021 its spread among birds has led to cross-species transmission causing epizootics among mammals, eventually impacting fur animal farms in Finland in 2023. To analyze the infectivity of the Finnish H5N1 isolates in human cells, representatives of diverse H5N1 isolates were selected based on the genetic differences, host animal species, and the year of occurrence. The infection kinetics of the selected H5N1 isolates from wild pheasant and fox, and fur animals blue fox and white mink were examined in human monocyte-derived dendritic cells (moDCs) with H5N1 human isolate as a control. Although the isolate from pheasant (a wild bird) showed weakly reduced replication and viral protein expression in human cells compared to mammalian isolates, no discernible differences in virus replication in moDCs was observed. This study revealed similar infectivity in human moDCs for all five H5N1 isolates, regardless of the observed genetic differences. While H5N1 human infections remain rare, the virus poses a risk for widespread epizootics in mammals such as fur animal farms and, more recently, dairy cattle.

Source: Emerging Microbes & Infections, https://www.tandfonline.com/doi/full/10.1080/22221751.2024.2447618

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Are we serologically prepared against an avian #influenza #pandemic and could seasonal flu #vaccines help us?

ABSTRACT

The current situation with H5N1 highly pathogenic avian influenza virus (HPAI) is causing a worldwide concern due to multiple outbreaks in wild birds, poultry, and mammals. Moreover, multiple zoonotic infections in humans have been reported. Importantly, HPAI H5N1 viruses with genetic markers of adaptation to mammals have been detected. Together with HPAI H5N1, avian influenza viruses H7N9 (high and low pathogenic) stand out due to their high mortality rates in humans. This raises the question of how prepared we are serologically and whether seasonal vaccines are capable of inducing protective immunity against these influenza subtypes. An observational study was conducted in which sera from people born between years 1925–1967, 1968–1977, and 1978–1997 were collected before or after 28 days or 6 months post-vaccination with an inactivated seasonal influenza vaccine. Then, hemagglutination inhibition, viral neutralization, and immunoassays were performed to assess the basal protective immunity of the population as well as the ability of seasonal influenza vaccines to induce protective responses. Our results indicate that subtype-specific serological protection against H5N1 and H7N9 in the representative Spanish population evaluated was limited or nonexistent. However, seasonal vaccination was able to increase the antibody titers to protective levels in a moderate percentage of people, probably due to cross-reactive responses. These findings demonstrate the importance of vaccination and suggest that seasonal influenza vaccines could be used as a first line of defense against an eventual pandemic caused by avian influenza viruses, to be followed immediately by the use of more specific pandemic vaccines.

Source: mBio, https://journals.asm.org/doi/10.1128/mbio.03721-24

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#Vaccination with different group 2 #influenza #subtypes alters epitope targeting and breadth of #hemagglutinin stem–specific human B cells

Abstract

The conserved influenza hemagglutinin stem, which is a target of cross-neutralizing antibodies, is now used in vaccine strategies focused on protecting against influenza pandemics. Antibody responses to group 1 stem have been extensively characterized, but little is known about group 2. Here, we characterized the stem-specific repertoire of individuals vaccinated with one of three group 2 influenza subtypes (H3, H7, or H10). Epitope mapping revealed two epitope supersites on the group 2 stem. Antibodies targeting the central epitope were broadly cross-reactive, whereas antibodies targeting the lower epitope had narrower breadth but higher potency against H3 subtypes. The ratio of B cells targeting each of the supersites varied with the vaccine subtype, leading to differences in the cross-reactivity of the B cell response. Our findings suggest that vaccine strategies targeting both group 2 stem epitopes would be complementary, eliciting broader and more potent protection against both seasonal and pandemic influenza strains.

Source: Science Translational Medicine, https://www.science.org/doi/10.1126/scitranslmed.adr8373

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Prior #infection with IBDV prolonged the shedding of a #mallard #H3N8 #influenza A virus (IAV) challenge from oropharyngeal cavity of some #chickens {...}

Abstract

Infectious bursal disease virus (IBDV) is endemic worldwide and causes immunosuppression in chickens. We hypothesized that a previous history of IBDV in chickens would render them more susceptible to infection by influenza A viruses (IAVs) from aquatic waterfowl reservoirs. To model this, we inoculated 14 day old specific pathogen free (SPF) chickens with a low pathogenicity avian influenza (LPAI) virus strain from a mallard (A/Mallard/Alberta/156/01 (H3N8)) and compared replication and shedding between immunocompetent chickens and chickens that had immune dysregulation due to a prior IBDV infection with strain F52/70 (genogroup A1B1) at 2 days of age. The mallard IAV strain replicated in the upper respiratory tract of the chickens, and virus was shed from the oropharyngeal cavity, but there was no shedding from the cloaca, and no transmission to sentinel chickens. Replication of the mallard IAV in the chicken host was associated with amino acid substitutions in the polymerase complex and HA. IBDV infection increased the average fold change of IAV replication in the trachea of chickens, prolonged the shedding of infectious IAV from 5 to 6 days in some chickens, increased the number of amino acid substitutions detected in the IAV population from 13 to 30, and significantly increased the number of mutations per IAV sample from 2.50 (SD +/- 1.83) in the Mock/IAV group to 4.75 (SD +/- 1.81) in the IBDV/IAV group (p < 0.01). Taken together, IBDV infection prolonged the shedding of the mallard IAV in some chickens and changed IAV intra-host evolution.

Source: BioRxIV, https://www.biorxiv.org/content/10.1101/2024.12.31.630863v1?rss=1

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Identification of a broad-inhibition #influenza #neuraminidase #antibody from pre-existing memory B cells

Highlights

-- Both NA-specific antibodies and memory B cells are detected in healthy adults

-- NA broad-inhibition monoclonal antibodies are derived from classical memory B cells

-- Broad inhibition monoclonal antibodies target the NA conserved enzymatic epitopes

-- NA broad-inhibition antibodies protect mice against H1N1 and H5N1-clade 2.3.4.4b

Summary

Identifying broadly reactive B precursor cells and conserved epitopes is crucial for developing a universal flu vaccine. In this study, using influenza neuraminidase (NA) mutant probes, we find that human pre-existing NA-specific memory B cells (MBCs) account for ∼0.25% of total MBCs, which are heterogeneous and dominated by class-unswitched MBCs. In addition, we identify three NA broad-inhibition monoclonal antibodies (mAbs) (BImAbs) that block the activity of NA derived from different influenza strains, including the recent cow H5N1. The cryoelectron microscopy (cryo-EM) structure shows that the BImAb targets the conserved NA enzymatic pocket and a separate epitope in the neighboring NA monomer. Furthermore, the NA BImAbs protect mice from the lethal challenge of the human pandemic H1N1 and H5N1. Our work demonstrates that the NA broad-inhibition precursor MBCs exist in healthy adults and could be targeted by the NA-based universal flu vaccine.

Source: Cell Host Microbe, https://www.sciencedirect.com/science/article/abs/pii/S1931312824004670?via%3Dihub

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#Combination #chemotherapy, a potential #strategy for reducing the emergence of #drug-resistant #influenza A variants

Natalia A. Ilyushina {a b}, Nicolai V. Bovin {c}, Robert G. Webster {a d}, Elena A. Govorkova  {a b}

a} Department of Infectious Diseases, St. Jude Children's Research Hospital, 332 N. Lauderdale, Memphis, TN 38105-2794, USA; b} The D.I. Ivanovsky Institute of Virology, Gamaleya 16, Moscow 123098, Russia; c} Shemyakin Institute of Bioorganic Chemistry, 16/10 Miklukho-Maklaya, Moscow 117997, Russia; d} Department of Pathology, University of Tennessee, Memphis, TN 38105, USA

Received 21 November 2005, Accepted 26 January 2006, Available online 21 February 2006.

Abstract

Rapid development of resistant influenza variants after amantadine treatment is one of the main drawbacks of M2 blockers. On the other hand, the emergence of variants with low susceptibility to the neuraminidase (NA) inhibitors is limited. In the present study we examined whether combination therapy with two classes of anti-influenza drugs can affect the emergence of resistant variants in vitro. We observed that virus yields of human A/Nanchang/1/99 (H1N1), A/Panama/2007/99 (H3N2), and A/Hong Kong/156/97 (H5N1) viruses in MDCK cells were significantly reduced (P < 0.005) when the cells were treated with the combination of amantadine and low doses of oseltamivir carboxylate (≤1 μM). After five sequential passages in MDCK cells, the M2 protein of viruses cultivated with amantadine alone mutated at positions V27A and S31N/I. Viruses cultivated with oseltamivir carboxylate (≥0.001 μM) possessed mutations in the hemagglutinin (HA) protein. These variants showed reduced efficiency of binding to sialic acid receptors and decreased sensitivity to NA inhibitor in plaque reduction assay. Importantly, no mutations in the HA, NA, and M2 proteins were detected when the drugs were used in combination. Our results suggest that combination chemotherapy with M2 blocker and NA inhibitor reduced the emergence of drug-resistant influenza variants in vitro. This strategy could be an option for the control of influenza virus infection, and combinations with other novel drugs should be explored.

Source: Antiviral Research, https://www.sciencedirect.com/science/article/abs/pii/S0166354206000349

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#USA, #NIH officials assess #threat of #H5N1

 {Excerpt, edited}

What

Highly pathogenic H5N1 avian influenza A virus (HPAI H5N1) remains a low risk to the general public, and public health experts in the United States believe that available treatments and vaccines, as well as those in development, are sufficient to prevent severe disease. However, the National Institutes of Health (NIH) and its federal partners remain focused on monitoring the virus and evaluating changes, according to leading officials at the National Institute of Allergy and Infectious Diseases (NIAID), part of the NIH.

In a commentary published in the New England Journal of Medicine, NIAID Director Jeanne M. Marrazzo, M.D., M.P.H., and Michael G. Ison, M.D., M.S., chief of the Respiratory Diseases Branch in NIAID’s Division of Microbiology and Infectious Diseases, say people should find a balance between enhanced vigilance and “business as usual” with respect to HPAI H5N1.

Since 1996, HPAI H5N1 influenza viruses have circulated in at least 23 countries. In late 2021, HPAI H5N1 spread from Europe to North America causing sporadic infections among wild birds and poultry farms. In 2022, the virus spread to South America where it devastated birds and marine mammals. In March 2024, USDA scientists identified HPAI H5N1 in U.S. dairy cows, and it subsequently reached herds in 16 states. The virus has been detected in dairy herds in three states over the past 30 days, according to USDA/APHIS. In 2024, the virus has caused 66 confirmed and 7 probable cases of influenza in people in the U.S. and one case in Canada. These human cases have been caused by either the H5N1 type circulating in birds (D1.1) or the type circulating in dairy cows (B3.13).

Against this backdrop, Drs. Marrazzo and Ison say there are four keys to controlling the current outbreak. The first imperative is timely, effective collaborations among investigators in human and veterinary medicine, public health, health care, and occupational workers, such as dairy and poultry workers.

This involves cultivating trust not only between numerous entities, but with people seeking care for symptoms of concern, including conjunctivitis, the authors write. Fortunately, so far most U.S. cases of HPAI H5N1 have been mild and resolved on their own without the need for treatment.

Their second key is a focus on the Canadian HPAI H5N1 patient, who developed respiratory failure and required life-saving medical intervention and treatment before recovering. The authors write that mutations found in the virus in this patient highlight an urgent need for vigilant disease surveillance to identify and assess viral changes to evaluate the risk for person-to-person transmission. Effective surveillance, they say, requires that complete genomic sequencing data from animals and people are made rapidly and readily available.

Without information pertaining to where and when isolates were collected, the data cannot be linked phylogenetically to other reported sequences, limiting insight into how the virus is spreading, they write. These data would also provide opportunity for early detection of mutations that might portend avidity for human respiratory epithelium, which may require as little as one mutation in the virus.

Third, researchers must continue to develop and test medical countermeasures—such as vaccines and therapies that eliminate or alleviate disease—against H5N1 and other influenza viruses. Fortunately, current vaccine candidates neutralize the circulating strains, which so far are susceptible to antivirals that could mitigate transmission and severity of illness, they write.

Lastly, Drs. Marrazzo and Ison encourage people to take precautions to prevent exposure to the virus and minimize the risk of infection. For example, people who work with poultry and cows should use personal protective equipment and educate themselves about occupational risks when working with birds and mammals, as CDC and USDA have repeatedly recommended.

Ideally, following these four steps will help scientists and public health officials investigating HPAI H5N1 to answer the many remaining questions more quickly about how the virus is spreading, evolving, and affecting people, other mammals, and birds.

Article: M Ison and J Marrazzo. The Emerging Threat of H5N1 to Human Health. NEJM DOI: 10.1056/NEJMe2416323 (2024).

Who: NIAID Director Jeanne M. Marrazzo, M.D., M.P.H., and Michael G. Ison, M.D., M.S., chief of the Respiratory Diseases Branch in NIAID’s Division of Microbiology and Infectious Diseases, are available for comment.

(...)

Source: US National Institute of Health, https://www.nih.gov/news-events/news-releases/nih-officials-assess-threat-h5n1

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Highly Pathogenic Avian #Influenza A(#H5N1) Virus #Infections in #Humans

Abstract

Background

Highly pathogenic avian influenza A(H5N1) viruses have caused widespread infections in dairy cows and poultry in the United States, with sporadic human cases. We describe characteristics of human A(H5N1) cases identified from March through October 2024 in the United States.

Methods

We analyzed data from persons with laboratory-confirmed A(H5N1) virus infection using a standardized case-report form linked to laboratory results from the Centers for Disease Control and Prevention influenza A/H5 subtyping kit.

Results

Of 46 case patients, 20 were exposed to infected poultry, 25 were exposed to infected or presumably infected dairy cows, and 1 had no identified exposure; that patient was hospitalized with nonrespiratory symptoms, and A(H5N1) virus infection was detected through routine surveillance. Among the 45 case patients with animal exposures, the median age was 34 years, and all had mild A(H5N1) illness; none were hospitalized, and none died. A total of 42 patients (93%) had conjunctivitis, 22 (49%) had fever, and 16 (36%) had respiratory symptoms; 15 (33%) had conjunctivitis only. The median duration of illness among 16 patients with available data was 4 days (range, 1 to 8). Most patients (87%) received oseltamivir; oseltamivir was started a median of 2 days after symptom onset. No additional cases were identified among the 97 household contacts of case patients with animal exposures. The types of personal protective equipment (PPE) that were most commonly used by workers exposed to infected animals were gloves (71%), eye protection (60%), and face masks (47%).

Conclusions

In the cases identified to date, A(H5N1) viruses generally caused mild illness, mostly conjunctivitis, of short duration, predominantly in U.S. adults exposed to infected animals; most patients received prompt antiviral treatment. No evidence of human-to-human A(H5N1) transmission was identified. PPE use among occupationally exposed persons was suboptimal, which suggests that additional strategies are needed to reduce exposure risk. (Funded by the Centers for Disease Control and Prevention.)

Source: New England Journal of Medicine, https://www.nejm.org/doi/full/10.1056/NEJMoa2414610

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#Critical #Illness in an #Adolescent with #Influenza A(#H5N1) Virus #Infection

To the Editor:

Highly pathogenic avian influenza A(H5N1) viruses are circulating among wild birds and poultry in British Columbia, Canada.1 These viruses are also recognized to cause illness in humans. Here, we report a case of critical illness caused by influenza A(H5N1) virus infection in British Columbia.

On November 4, 2024, a 13-year-old girl with a history of mild asthma and an elevated body-mass index (the weight in kilograms divided by the square of the height in meters) of greater than 35 presented to an emergency department in British Columbia with a 2-day history of conjunctivitis in both eyes and a 1-day history of fever. She was discharged home without treatment, but cough, vomiting, and diarrhea then developed, and she returned to the emergency department on November 7 in respiratory distress with hemodynamic instability. On November 8, she was transferred, while receiving bilevel positive airway pressure, to the pediatric intensive care unit at British Columbia Children’s Hospital with respiratory failure, pneumonia in the left lower lobe, acute kidney injury, thrombocytopenia, and leukopenia (...). A nasopharyngeal swab obtained at admission was positive for influenza A but negative for A(H1) and A(H3) by the BioFire Respiratory Panel 2.1 assay (BioFire Diagnostics). Reflex testing of the specimen with the Xpert Xpress CoV-2/Flu/RSV plus assay (Cepheid) revealed an influenza A cycle threshold (Ct) value of 27.1. This finding indicates a relatively high viral load for which subtyping would be expected; the lack of subtype identification suggested infection with a novel influenza A virus. Oseltamivir treatment was started on November 8 (Table S2), and the use of eye protection, N95 respirators, and other precautions against droplet, contact, and airborne transmission were implemented.

A reverse-transcriptase–polymerase-chain-reaction (RT-PCR) test specific for influenza A(H5)2 was positive on the day of admission. The patient had signs of respiratory deterioration — chest radiographs were consistent with progression to acute respiratory distress syndrome (...) — which prompted tracheal intubation and initiation of venovenous extracorporeal membrane oxygenation (ECMO) on November 9. Continuous renal replacement therapy was initiated on November 10. Combination antiviral treatment with amantadine (initiated on November 9) and baloxavir (initiated on November 11) was added to ongoing treatment with oseltamivir. Bacterial cultures of blood (samples obtained at admission) and endotracheal aspirate (obtained after intubation) yielded no growth.

Because of concern for cytokine-mediated hemodynamic instability, plasma exchange was performed daily from November 14 through November 16. Serial influenza A–specific RT-PCR tests showed increasing Ct values, which suggested a decline in the viral RNA load in serum and a decline in viral RNA in upper- and lower-respiratory specimens shortly after the initiation of antiviral treatment, with the first negative RT-PCR result for serum obtained on November 16 (...). It is notable that lower-respiratory specimens consistently yielded lower Ct values than upper-respiratory specimens, a finding that suggested higher viral levels in the lower-respiratory tract (...).

Influenza A(H5N1) virus was cultured from respiratory specimens obtained between November 8 and November 12 but not from subsequent respiratory specimens or from any serum specimens (...). No evidence of reduced susceptibility to any of the three antiviral agents used in treatment was observed in serial respiratory specimens by either genomic analysis or phenotypic testing with the NA-Star influenza neuraminidase inhibitor resistance detection kit (ThermoFisher Scientific) (...). The patient’s respiratory status improved, ECMO was discontinued on November 22, and the patient’s trachea was extubated on November 28.

The viral genome sequence obtained from a tracheal-aspirate specimen collected on November 9 (8 days after the onset of symptoms) was reconstructed as described previously.3 The virus was typed as clade 2.3.4.4b, genotype D1.1,4 most closely related to viruses detected in wild birds in British Columbia around the same time (...). Markers of adaptation to humans were detected in the tracheal-aspirate specimen collected on November 9: the E627K mutation was detected (52% allele frequency) in the polymerase basic 2 (PB2) gene product, and analysis of the H5 hemagglutinin (HA) gene yielded ambiguous calls in the codons for amino acid residues E186 (E190 according to H3 mature HA numbering) — 28% allele frequency for E186D — and Q222 (Q226 according to H3 mature HA numbering) — 35% allele frequency for Q222H. The mutations in the H5 HA gene have previously been shown to increase binding to α2-6–linked sialic acids, which act as receptors that facilitate viral entry into cells in the human respiratory tract and enable viral replication.5

Highly pathogenic avian influenza A(H5N1) virus infection acquired in North America can cause severe human illness. Evidence for changes to HA that may increase binding to human airway receptors is worrisome.

Agatha N. Jassem, Ph.D., British Columbia Centre for Disease Control, Vancouver, BC, Canada; Ashley Roberts, M.D., British Columbia Children’s Hospital, Vancouver, BC, Canada; John Tyson, Ph.D., James E.A. Zlosnik, Ph.D., Shannon L. Russell, Ph.D., British Columbia Centre for Disease Control, Vancouver, BC, Canada; Jessica M. Caleta, M.Sc., Public Health Agency of Canada, Winnipeg, MB, Canada; Eric J. Eckbo, M.D., British Columbia Centre for Disease Control, Vancouver, BC, Canada; Ruimin Gao, Ph.D., Taeyo Chestley, Ph.D., Public Health Agency of Canada, Winnipeg, MB, Canada; Jennifer Grant, M.D., British Columbia Centre for Disease Control, Vancouver, BC, Canada; Timothy M. Uyeki, M.D., M.P.H., Centers for Disease Control and Prevention, Atlanta, GA; Natalie A. Prystajecky, Ph.D., British Columbia Centre for Disease Control, Vancouver, BC, Canada; Chelsea G. Himsworth, D.V.M., Ph.D., British Columbia Ministry of Agriculture and Food, Abbotsford, BC, Canada; Elspeth MacBain, M.D., British Columbia Children’s Hospital, Vancouver, BC, Canada; Charlene Ranadheera, Ph.D., Public Health Agency of Canada, Winnipeg, MB, Canada; Lynne Li, M.D., British Columbia Children’s Hospital, Vancouver, BC, Canada; Linda M.N. Hoang, M.D., British Columbia Centre for Disease Control, Vancouver, BC, Canada; Nathalie Bastien, Ph.D., Public Health Agency of Canada, Winnipeg, MB, Canada; David M. Goldfarb, M.D., British Columbia Children’s Hospital, Vancouver, BC, Canada.

Source: New England Journal of Medicine, https://www.nejm.org/doi/full/10.1056/NEJMc2415890

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Immunogenicity of inactivated #H5 avian #influenza #vaccine used in commercial laying #pullet in #Tehran province

Abstract

Highly pathogenic avian influenza (HPAI) is a viral disease caused by some H5 and H7 subtypes of influenza virus type A in most species of birds, especially poultry. HPAI viruses are amongst the most challenging viruses that threaten both human and animal health. Consequently, various strategies such as the use of vaccines have been proposed to control the disease. After a catastrophic pandemic and the failure of conventional methods (elimination and extermination) in Iran, multiple vaccines has been used to control the disease. This study investigates the immunogenicity of two recombinant inactivated commercial vaccines of H5N1 and H5N3 subtypes in laying pullet flocks in Tehran Province, Iran. From 32 halls in 6 breeding units of laying pullets, 3200 sera and 800 tracheal and cloacal swabs were collected. After collecting the samples, Serum neutralisation (SN) and hemagglutination inhibition (HI) tests were conducted on sera to determine the serum titers of H5 specific antibody obtained from vaccine inoculation in three steps: before, after first vaccination and after the second vaccination (booster). SN and HI tests were carried out by the alpha and beta methods on the pooled samples by the vaccine type (as antigen for HI and SN), and the results were compared. The PCR was performed on the tracheal and cloacal swab samples to possibly detect the HA (H5)virus in the studied flocks. The HI test results showed that both vaccines had a Serum antibody titre above 5 (log2) after two vaccination rounds, indicating a desirable immunogenic response. The SN test results also showed a neutralisation index above 104.5 for both vaccines, indicating more than 50% reduction in antigenicity of the virus. The PCR results were negative. This study was the first investigation of immunogenicity following two-time vaccination against H5 subtype vaccines in Iranian poultry flocks, indicated suitable antibody titer against the influenza virus in vaccinated flocks.

Source: Archives of Razi Institute, https://archrazi.areeo.ac.ir/article_130878.html

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Spatio-temporal #dynamics and #risk cluster #analysis of highly pathogenic avian #influenza (#H5N1) in #poultry: Advancing #outbreak #management through customized regional strategies in #Egypt

ABSTRACT 

Background: 

Highly pathogenic avian influenza (HPAI) (H5N1) has been endemic in Egypt for almost two decades, profoundly impacting both the poultry industry and public health. Egypt stands as a prominent epicenter for HPAI H5N1 outbreaks in Africa, marked by the highest number of positive human cases. Despite continuous governmental efforts, prior research underscored the inadequacy of strategies in controlling the virus spread. 

Aim: 

This study identified spatiotemporal patterns and high-risk clusters of HPAI H5N1 outbreaks at the subdistrict level. 

Methods: 

This study involved trial tracking of HPAI H5N1 endemicity dynamics, enabling tailored interventions at a regional level based on robust epidemiological investigations to address the persistent challenge of HPAI H5N1 in Egypt. This study illuminated spatiotemporal outbreak dynamics, with specific attention on Menofia governorate. 

Results: 

Despite the region’s early poultry impacts, initial outbreaks did not originate from Menofia in studied epidemic waves (EWs). Outbreak risk spatial distribution displayed an escalating pattern at the northern border, followed by risk reduction through the sixth EW. The predominant hot spot region was localized within rural districts, particularly villages, while urbanization coincided with lower outbreak density. Observed smoothed densities revealed epidemic propagation within urban centers, preceding its transition to new areas and establishing direct connections with neighboring cities. Primary cluster prognostication was plausible, occurring in regions previously hosting elevated relative risk clusters during preceding EWs. Identification of enduring pinpoint clusters, persistent for extended durations, indicated close contact dynamics and localized viral circulation within populations. 

Conclusion: 

This study highlights the significance of customized regional interventions based on the rigorous epidemiological framework. This approach is pivotal in the profound comprehension of endemicity dynamics, efficiently limits geographical infection spread, and contains outbreaks within delineated areas.

Source: Open Veterinary Journal, https://doi.org/10.5455/OVJ.2024.v14.i11.20

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A Potent #Pandemic Avian #Influenza Virus #Vaccine Based on a 4th Generation Fully Deleted #Adenoviral #Vector

Abstract

The GreVac system was developed as a fast and flexible plug-and-play vaccine platform based on an architecture of fully deleted (fd) helper virus-independent (hi) adenoviral (Ad) vectors. The present study established the potency of the GreVac technology. It demonstrated that the GreFluVie5 vaccine fully protected mice against lethal challenges with the A/Vietnam/1203/2004 (H5N1) pandemic avian influenza virus. The GreFluVie5 vector delivered a transgene expression cassette for the H5 hemagglutinin and N1 neuramidase influenza genes. Its fd Ad genome was carried in a capsid of the human serotype 5 (Ad5). The efficacies of three different doses and three different administration routes were compared in the mouse model. The vaccine fully protected animals against viral challenges with the wild-type A/Vietnam/1203/2004 virus, whose replication in the recipients' lungs was terminated. It induced strong immune responses. The present experiments also revealed that the intra muscular (i.m.) delivery route of GreFluVie5 was more efficient than sub cutaneous (s.c.) or intra nasal (i.n.) ones. Based on the results of this trial and GreVac's intrinsic versatility and fast development time, we believe that this platform is ideally suited to swiftly deliver powerful vaccines to infectious diseases with high eruption potentials.

Source: BioRxIV, https://www.biorxiv.org/content/10.1101/2024.12.30.630761v1

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#France - High pathogenicity avian #influenza #H5 viruses (#poultry) (Inf. with) - Immediate notification

 Two poultry farms in Normandie Region.

Source: WOAH, https://wahis.woah.org/#/in-review/6127

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

 Backyard poultry in Tiranë Region.

Source: WOAH, https://wahis.woah.org/#/in-review/6130

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#Germany - #Influenza A #H5N1 viruses of high pathogenicity (Inf. with) (non-poultry including wild birds) (2017-) - Immediate notification

 A wild bird in Brandenburg Region. 

Source: WOAH, https://wahis.woah.org/#/in-review/6133

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A low pathogenic avian #influenza A/Mallard/South Korea/KNU2019-34/2019 (#H1N1) virus has the potential to increase the #mammalian #pathogenicity

Abstract

Influenza, a highly contagious respiratory infectious disease caused by an influenza virus, is a threat to public health worldwide. Avian influenza viruses (AIVs) have the potential to cause the next pandemic by crossing the species barrier through mutation of viral genome. Here, we investigated the pathogenicity of AIVs obtained from South Korea and Mongolia during 2018–2019 by measuring viral titers in the lungs and extrapulmonary organs of mouse models. In addition, we assessed the pathogenicity of AIVs in ferret models. Moreover, we compared the ability of viruses to replicate in mammalian cells, as well as the receptor-binding preferences of AIV isolates. Genetic analyses were finally performed to identify the genetic relationships and amino acid substitutions between viral proteins during mammalian adaptation. Of the 24 AIV isolates tested, A/Mallard/South Korea/KNU2019-34/2019 (KNU19-34; H1N1) caused severe bodyweight loss and high mortality in mice. The virus replicated in the lungs, kidneys, and heart. Importantly, KNU19-34-infected ferrets showed high viral loads in both nasal washes and lungs. KNU19-34 replicated rapidly in A549 and bound preferentially to human like α2,6-linked sialic acids rather than to avian-like α2,3-linked sialic acids, similar to the pandemic A/California/04/2009 (H1N1) strain. Gene segments of KNU19-34 were distributed in Egypt and Asia lineages from 2015 to 2018, and the virus had several amino acid substitutions compared to H1N1 AIV isolates that were non-pathogenic in mice. Collectively, the data suggest that KNU19-34 has zoonotic potential and the possibility of new mutations responsible for mammalian adaptation.

Source: Virologica Sinica, https://www.sciencedirect.com/science/article/pii/S1995820X24002062?via%3Dihub

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LC-MS/MS characterization of #SOBERANA®02, a #RBD - #tetanus toxoid conjugate #vaccine against #SARS-CoV-2

Abstract

SOBERANA-02 is a safe and effective conjugate vaccine against SARS-CoV-2, produced using the maleimide-thiol chemistry. In this vaccine, the Cys538 in the recombinant receptor binding domain (RBD) of SARS-CoV-2 is linked, through a thiosuccinimide linker, to lysine residues of tetanus toxoid (TT) preparation. LC-MS/MS analysis revealed that TT is a complex mixture of proteins, similar to other TTs where the detoxified tetanus neurotoxin (d-TeNT) has been shown to be the most abundant protein (30-56%), regardless the quantification method used. The fifteen most abundant proteins account for approximately 78% of the total proteins. LC-MS/MS analysis of the activation process showed that 102 out of 107 lysine residues in the d-TeNT incorporated a maleimide group. In contrast, when tryptic peptides isolated by Ni2+-NTA affinity chromatography, were analyzed by LC-MS/MS, only 22 Lys residues in the d-TeNT were cross-linked to the RBD C-terminal tryptic peptide (538CVNF541-HHHHHH), probably due to steric hindrance. Twelve and eighteen conjugation sites were assigned based on the identification of linear peptides carrying a conjugated lysine residues (K(+1454.58 Da) or K(+1472.59 Da)) and cross-linked peptides with stabilized linker forms, respectively. Eight conjugation sites were coincidently assigned by both strategies. The assignment of the conjugation sites was manually validated by observed regularities (z equal or higher to 3+, XIC, immonium ions, specific linker fragment ions) not considered by the identification software (PEAKS, Kojak and pLink2). The RBD was also conjugated, but to a lesser extent, to ten other low abundance carrier proteins. To our knowledge, this work is the first report of conjugation site assignment in a TT-based conjugate vaccine.

Source: BioRxIV, https://www.biorxiv.org/content/10.1101/2024.12.27.630511v1?rss=1

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Enhanced #RNA #replication and #pathogenesis in recent #SARS-CoV-2 #variants harboring the L260F mutation in NSP6

Abstract

The COVID-19 pandemic has been driven by SARS-CoV-2 variants with enhanced transmission and immune escape. Apart from extensive evolution in the Spike protein, non-Spike mutations are accumulating across the entire viral genome and their functional impact is not well understood. To address the contribution of these mutations, we reconstructed genomes of recent Omicron variants with disabled Spike expression (replicons) to systematically compare their RNA replication capabilities independently from Spike. We also used a single reference replicon and complemented it with various Omicron variant Spike proteins to quantify viral entry capabilities in single-round infection assays. Viral entry and RNA replication were negatively correlated, suggesting that as variants evolve reduced entry functions under growing immune pressure on Spike, RNA replication increases as a compensatory mechanism. We identified multiple mutations across the viral genome that enhanced viral RNA replication. NSP6 emerged as a hotspot with a distinct L260F mutation independently arising in the BQ.1.1 and XBB.1.16 variants. Using mutant and revertant NSP6 viral clones, the L260F mutation was validated to enhance viral replication in cells and increase pathogenesis in mice. Notably, this mutation enhanced host lipid droplet consumption by NSP6 without impacting its known ER-zippering function or double-membrane vesicle morphology. Collectively, a systematic analysis of RNA replication of recent Omicron variants defined NSP6 key role in viral RNA replication that provides insight into evolutionary trajectories of recent variants with possible therapeutic implications.

Source: BioRxIV, https://www.biorxiv.org/content/10.1101/2024.12.30.628795v1?rss=1

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#USA, #Oregon: State ends year with highest #pertussis case count since 1950

As Oregon sweeps past the 1,100 cases mark, health officials remind everyone that vaccination against whooping cough is best way to prevent transmission

PORTLAND, Ore.—Oregon swept past the 1,100 mark for the number of pertussis cases it’s seen during 2024, beating its 2012 record of 910 cases in a single year—and making the need for people to stay up to date with their vaccinations all the more urgent.

As of Monday, Dec. 30, Oregon Health Authority registered 1,105 cases of pertussis—also known as whooping cough—during 2024. There were 44 outbreaks, although the majority of cases were sporadic individual or household-related cases and not associated with outbreaks. The 2024 count represents the highest number of pertussis cases reported in Oregon in a single year since 1950, when 1,420 cases were reported.

Since 2003, eight Oregonians with pertussis have died. Five were younger than 4 months old, and there have been three deaths in adults – one in 2023 and two in 2024.

While Oregon didn’t beat its 74-year record for most cases in a year, 1,105 is still an extremely high number for a vaccine-preventable disease, said Paul Cieslak, M.D., medical director for communicable diseases and immunizations at OHA’s Public Health Division. It’s also a stark reminder of how quickly the bacterial infection can spread and cause illness, particularly among people who are under- or unvaccinated.

“The pertussis vaccine is a public health success story in terms of its effectiveness in reducing severe illness and deaths from the disease—particularly among infants,” Cieslak said.

According to data from the epidemiologists in Oregon Public Health Division’s Acute and Communicable Disease Prevention Section, the median age of the 2024 cases is 12; 7.2% of cases are less than a year old, 80% are 18 or younger and 50% are female. About half of the cases are up to date with pertussis vaccines.

Lane County has reported the highest number of pertussis cases this year with 315. Rounding out the top five counties are Multnomah, 235 cases; Clackamas, 135; Washington, 119; and Marion, 75.

Pertussis case counts vary considerably from year to year, routinely reaching triple digits. However, during the COVID-19 pandemic, restrictions such as masking requirements and school closures were in effect, which kept annual case counts low, Cieslak said. Vaccination rates also slipped.

“People were less motivated to get vaccinated against pertussis when there was less concern they would be exposed to the infection in the first place,” he said.

But with pertussis activity so high this year, there are more opportunities for people to be exposed, Cieslak noted. Those who are unvaccinated or too young to be vaccinated, such as infants, are at the highest risk from infection, with babies most likely to be hospitalized with pertussis.

But there are ways to protect vulnerable individuals. Pregnant people can protect their young babies by getting the Tdap vaccine—which protects against tetanus, diphtheria and pertussis—at 27–36 weeks’ gestation. Mothers will make antibodies and pass them to their babies across the placenta, protecting them from the moment of birth. It is recommended during each pregnancy.

“In recent years, about two-thirds of pregnant Oregonians have been getting vaccinated during pregnancy,” Cieslak said. “However, only 11 of the mothers of the 80 infant cases this year had documentation of having gotten the recommended shot.”

Vaccination against pertussis is routinely recommended for infants, children, adolescents and adults. Children should receive the DTaP vaccine against diphtheria, tetanus and pertussis at 2, 4, 6 and 15 to 18 months old, and again at age 4 to kindergarten age. All persons 10 years old and older should receive a single dose of Tdap.

“Additionally, when pertussis strikes a household in which an infant or pregnant person lives, we recommend all members of the household receive a course of antibiotics effective against Bordetella pertussis—typically, a five-day course of azithromycin,” Cieslak said.

Source: Department of Health, https://content.govdelivery.com/accounts/ORHA/bulletins/3c9f333

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#Risk #assessment of 2024 #cattle #H5N1 using age-stratified #serosurveillance data

ABSTRACT

The highly pathogenic avian influenza virus A(H5N1) clade 2.3.4.4b has caused a human outbreak in North America since March 2024. Here, we conducted a serosurveillance study to determine the risk of A(H5N1) clade 2.3.4.4b (2024 cattle H5N1) to general population. In the initial screening of 180 serum specimens encompassing all age groups, 2.2% (4/180) had detectable neutralizing antibody (nAb) titers against 2024 cattle H5N1, with all collected from older adults aged ≥60 years old. Further screening showed that 5.0% (15/300) of adults aged ≥70 years old had detectable nAb titers against the 2024 cattle H5N1. All serum specimens with nAb titer of ≥40 had detectable HI titer, and there was a positive correlation between nAb titer and HA binding (r=0.3311, 95% confidence interval 0.2264 to 0.4283; P<0.0001). The nAb titer against seasonal H1N1 virus was 3.9-fold higher for patients with detectable H5N1 nAb than those without (geometric mean titer: 108.5 [95% CI 56.3-209.1] vs 27.9 [95% CI 21.0-37.0], P=0.0039), but there was no statistically significant difference between H5N1 and H3N2 nAb titer. There was no difference in demographics, comorbidities and clinical frailty scores between individuals with detectable H5N1 nAb and those without. Our findings suggest that most individuals lack nAb response against 2024 cattle H5N1 and there is an urgency to develop and evaluate H5N1 vaccine or prophylactic monoclonal antibodies. Immune imprinting may be responsible for the cross neutralization between H5N1 and H1N1 among older adults.

Source: MedRxIV, https://www.medrxiv.org/content/10.1101/2024.12.23.24319580v1

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#Origin, spread, and interspecies #transmission of a dominant #genotype of BJ/94 #lineage #H9N2 avian #influenza viruses with increased #threat

Abstract

The H9N2 subtype of avian influenza viruses (AIVs) is widely prevalent in poultry and wild birds globally, with occasional transmission to humans. In comparison to other H9N2 lineages, the BJ/94 lineage has raised more public health concerns; however, its evolutionary dynamics and transmission patterns remain poorly understood. In this study, we demonstrate that over three decades (1994–2023), BJ/94 lineage has undergone substantial expansion in its geographical distribution, interspecies transmission, and viral reassortment with other AIV subtypes, increasing associated public health risks. These changes were primarily driven by the emergence of a dominant genotype G57. In the first decade, G57 emerged in East China and rapidly adapted to chickens and spread across China. Since 2013, the G57 genotype has expanded beyond China into eight other countries and reassorted with various AIV subtypes to form new zoonotic reassortants. Chickens have played a key role in the generation and circulation of the G57 viruses, with ducks and other poultry species likely assuming an increasingly importantly role. Over the past decade, G57 has been more frequently detected in wild birds, mammals, and humans. Additionally, Vietnam has emerged as a new hotspot for the international spread of G57. Our results suggest that the BJ/94 lineage H9N2 virus may continue to overcome geographical and species barriers, with potentially more severe consequences.

Source: Virus Evolution, https://academic.oup.com/ve/article/10/1/veae106/7919252

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#Germany - High pathogenicity avian #influenza #H5 viruses (#poultry) (Inf. with) - Immediate notification

 A poultry farm in Bayern Region.

Source: WOAH, https://wahis.woah.org/#/in-review/6131

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High Pathogenicity Avian #Influenza Virus (HPAIV) #H5N1 clade 2.3.4.4b recovered from a kelp #gull (Larus dominicanus) in the South Shetland Islands, #Antarctica

Abstract

Whole-genome analysis of the earliest-detected High Pathogenicity Avian Influenza Virus (HPAIV) H5N1 clade 2.3.4.4b detected in Hannah Point, Antarctica (January 2024) reveals close relatedness to strains that circulated in pinnipeds and seabirds along the Atlantic coast of South America during the second half of 2023.

Source: BioRxIV, https://www.biorxiv.org/content/10.1101/2024.12.29.630510v1?rss=1

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Dona Antonia de Ipenarrieta y Galdos and her Son, Diego Velazquez (c.1631)

 

Credits: Public Domain.

Source: WikiArt, https://www.wikiart.org/en/diego-velazquez/dona-antonia-de-ipenarrieta-y-galdos-and-her-son

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The #PA-X #host shutoff site 100 V exerts a contrary effect on viral #fitness of the highly pathogenic #H7N9 #influenza A virus in mice and chickens

ABSTRACT

Several viruses, including influenza A virus (IAV), encode viral factors to hijack cellular RNA biogenesis processes to direct the degradation of host mRNAs, termed “host shutoff.” Host shutoff enables viruses to simultaneously reduce antiviral responses and provides preferential access for viral mRNAs to cellular translation machinery. IAV PA-X is one of these factors that selectively shuts off the global host genes. However, the specific role of PA-X host shutoff activity in viral fitness of IAV remains poorly understood. Herein, we successfully mapped PA-X 100 V as a novel site important for host shutoff of the H7N9 and H5N1 viruses. By analysing the polymorphism of this residue in various subtype viruses, we found that PA-X 100 was highly variable in H7N9 viruses. Structural analysis revealed that 100 V was generally close to the PA-X endonuclease active site, which may account for its host shutoff activity. By generating the corresponding mutant viruses derived from the parental H7N9 virus and the PA-X-deficient H7N9 virus, we determined that PA-X 100 V significantly enhanced viral fitness in mice while diminishing viral virulence in chickens. Mechanistically, PA-X 100 V significantly increased viral polymerase activity and viral replication in mammalian cells. Furthermore, PA-X 100 V highly blunted the global host response in 293T cells, particularly restraining genes involved in energy metabolism and inflammatory response. Collectively, our data provided information about the intricate role of the PA-X host shutoff site in regulating the viral fitness of the H7N9 influenza virus, which furthers our understanding of the complicated pathogenesis of the influenza A virus.

Source: Virulence, https://www.tandfonline.com/doi/full/10.1080/21505594.2024.2445238

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#USA, Snow #Geese Test Presumptive Positive for Avian #H5 #Influenza; #Delaware #poultry producers encouraged to take precautions

 {Excerpt}

DOVER, Del. (Dec. 28, 2024) – The Delaware Department of Natural Resources and Environmental Control (DNREC) and the Delaware Department of Agriculture (DDA) announced today that laboratory testing conducted by the University of Delaware’s Allen Laboratory, part of the National Animal Health Laboratory Network, has returned presumptive positive findings of H5 avian influenza in sick and dead snow geese collected on December 27, 2024, in coastal Sussex County. 

In response to the findings, the state of Delaware has established a Joint Information Center with DNREC, DDA, the Delaware Division of Public Health (DPH) and the Delaware Emergency Management Agency (DEMA).

The detections mark the Delmarva region’s most recent confirmation of H5 avian influenza in wild birds since May 2022, when the virus was found through wildlife surveillance in black vultures in Harford County, Md. Avian influenza is known to be carried by wild birds, especially waterfowl, raptors, and vultures.

Avian influenza is a highly contagious airborne respiratory virus that spreads quickly among birds through nasal and eye secretions and manure. Snow geese, which are waterfowl, are known to migrate from the Arctic and form large flocks in Delaware each winter. Due to close contact with thousands of other snow geese while feeding and roosting, they can get sick and die. It is unknown when or where the snow geese may have acquired the virus given their highly migratory nature and association with other waterfowl and waterbirds throughout the Atlantic Flyway through which they travel into Delaware and more southern states.

People should not touch or handle injured, sick, or dead birds. Special attention should be paid to keep pets and children away from these wild birds and bird droppings.

Even with the ongoing detections of HPAI in wild birds, poultry, and dairy cattle in North America, continuing testing of people who are in close contact with infected animals indicates a low risk to the general public’s health. The H5N1 virus has infected very few people and has not been documented to be transmitted between people. The proper handling and cooking of all poultry and eggs to an internal temperature of 165°F is recommended as a general food safety precaution.

(...)

Source: Department of Health, https://news.delaware.gov/2024/12/28/snow-geese-test-presumptive-positive-for-avian-influenza-delaware-poultry-producers-encouraged-to-take-precautions/

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