#aH5n1

#Evidence of #Influenza A(#H5N1) #Spillover Infections in #Horses, #Mongolia

Source: Emerging Infectious Diseases Journal, https://wwwnc.cdc.gov/eid/article/31/1/24-1266_article

Abstract
Recent outbreaks of influenza A(H5N1) have affected many mammal species. We report serologic evidence of H5N1 virus infection in horses in Mongolia. Because H3N8 equine influenza virus is endemic in many countries, horses should be monitored to prevent reassortment between equine and avian influenza viruses with unknown consequences.

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#aH3n8 #aH5n1 #abstract #avianInfluenza #equineInfluenza #horses #mongolia #research #seroprevalence

#Transmission #dynamics of highly pathogenic avian #influenza virus at the #wildlife#poultry – #environmental #interface: A case study

Source: OneHealth, https://www.sciencedirect.com/science/article/pii/S2352771424002581?via%3Dihub

Abstract
Avian influenza viruses (AIVs) regularly circulate between wild and domestic bird populations. Following several high-profile outbreaks, highly pathogenic AIVs (HPAIV) with zoonotic potential have been the subject of increasing attention. While we know that HPAIV is transmitted between domestic birds, wildlife, and the environment, little is known about persistence and spillover/back at these interfaces. We integrated the test results of samples collected on and around an infected domestic poultry premise (IP) where H5N1 HPAIV was confirmed in a flock of poultry in 2022 in Southern Ontario, Canada to explore the transmission cycle of AIVs in wildlife and the environment. We sampled a captive flock of Mallards (Anas platyrhynchos) that resided on site, sediment samples collected from water bodies on site, and examined samples collected through surveillance within a 100 km radius of the IP from live wild ducks and sick and dead wildlife. We found serologic evidence of H5 exposure in the captive mallards that resided on site despite no evidence of morbidity or mortality in these birds and no PCR positive detections from samples collected at two different timepoints. Genetic material from the same H5N1 HPAIV subtype circulating in the domestic birds and from low pathogenicity avian influenza viruses were detected in wetlands on site. The results of live and sick and dead surveillance conducted within a 100 km radius confirmed that the virus was circulating in wildlife before and after IP confirmation. These results suggest that biosecurity remains the most critical aspect of minimising spillover/back risk in a virus that has been shown to circulate in asymptomatic wild birds and persist in the surrounding environment.

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#aH5n1 #abstract #avianInfluenza #AVIANINFLUENZA #birdFlu #canada #h5n1 #health #news #ontario #poultry #research #WILDBIRDS

Establishing #methods to #monitor #H5N1 #influenza virus in dairy #cattle #milk

Source: MedRxIV, https://www.medrxiv.org/content/10.1101/2024.12.04.24318491v1

Abstract
Highly Pathogenic Avian Influenza strain H5N1 has caused a multi-state outbreak among US dairy cattle, spreading across 15 states and infecting hundreds of herds since its onset. We rapidly developed and optimized PCR-based detection assays and sequencing protocols to support H5N1 molecular surveillance. Using 214 retail milk from 20 states for methods development, we found that H5N1 concentrations by digital PCR strongly correlated with qPCR cycle threshold (Ct) values, with dPCR exhibiting greater sensitivity. We also found that metagenomic sequencing after hybrid selection was best for higher concentration samples while amplicon sequencing performs best for lower concentrations. By establishing these methods, we were able to support the creation of a statewide surveillance program to test bulk milk samples monthly from all cattle dairy farms within Massachusetts, which remain negative to date. The methods, workflow, and recommendations described here provide a framework for others aiming to conduct H5N1 surveillance efforts.

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#aH5n1 #abstract #avianInfluenza #AVIANINFLUENZA #birdFlu #dairyCow #dairyProducts #diagnosticTests #foodSafety #h5n1 #health #massachusetts #news #research #USA

#Croatia – High pathogenicity avian #influenza #H5N1 viruses (#poultry) (Inf. with) – Immediate notification

Source: WOAH, https://wahis.woah.org/#/in-review/6094

A poultry farm in Zagrebačka Region.

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#aH5n1 #avianInfluenza #croatia #poultry #updates #WOAH

#USA, #Monitoring for Avian #Influenza A(#H5) Virus In #Wastewater {Dec. 6 ’24}

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

{Excerpt}

Time Period: November 24 – November 30, 2024

H5 Detection: 43 sites (14.7%)

No Detection: 249 sites (85.3%)

No samples in last week: 52 sites

(…)

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#aH5n1 #avianInfluenza #updates #USCDC #USA #wastewater

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

Source: WOAH, https://wahis.woah.org/#/in-review/6090

Wild birds in Friesland and Groningen Regions.

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#aH5n1 #avianInfluenza #theNetherlands #updates #WILDBIRDS #WOAH

A single #mutation in #bovine #influenza #H5N1 #hemagglutinin switches specificity to #human #receptors

Source: Science, https://www.science.org/doi/10.1126/science.adt0180

Editor’s summary

In 2021, a highly pathogenic influenza H5N1 clade 2.3.4.4b virus was detected in North America that is capable of infecting a diversity of avian species, marine mammals, and humans. In 2024, clade 2.3.4.4b virus spread widely in dairy cattle in the US, causing a few mild human cases, but retaining specificity for avian receptors. Historically, this virus has caused up to 30% fatality in humans, so Lin et al. performed a genetic and structural analysis of the mutations necessary to fully switch host receptor recognition. A single glutamic acid to leucine mutation at residue 226 of the virus hemagglutinin was sufficient to enact the change from avian to human specificity. In nature, the occurrence of this single mutation could be an indicator of human pandemic risk. —Caroline Ash

Abstract

In 2024, several human infections with highly pathogenic clade 2.3.4.4b bovine influenza H5N1 viruses in the United States raised concerns about their capability for bovine-to-human or even human-to-human transmission. In this study, analysis of the hemagglutinin (HA) from the first-reported human-infecting bovine H5N1 virus (A/Texas/37/2024, Texas) revealed avian-type receptor binding preference. Notably, a Gln226Leu substitution switched Texas HA binding specificity to human-type receptors, which was enhanced when combined with an Asn224Lys mutation. Crystal structures of the Texas HA with avian receptor analog LSTa and its Gln226Leu mutant with human receptor analog LSTc elucidated the structural basis for this preferential receptor recognition. These findings highlight the need for continuous surveillance of emerging mutations in avian and bovine clade 2.3.4.4b H5N1 viruses.

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#aH5n1 #abstract #avianInfluenza #AVIANINFLUENZA #birdFlu #dairyCow #h5n1 #health #news #research

#USA, Confirmed #human #H5N1 virus cases summary during 2024 #outbreak, by state and exposure source, as of Nov. 4 ’24: One new case, total = 58

Source: US Centers for Disease Control and Prevention, https://www.cdc.gov/bird-flu/situation-summary/?CDC_AAref_Val=https://www.cdc.gov/flu/avianflu/avian-flu-summary.htm

{Excerpt}

Exposure Source
[State – Cattle – Poultry – Unknown – State Total]
1) California – 31 – 0 – 1 – 32 {+1}
2) Colorado – 1 – 9 – 0 – 10
3) Michigan – 2 – 0 – 0 – 2
4) Missouri – 0 – 0 – 1 – 1
5) Oregon – 0 – 1 – 0 – 1
6) Texas – 1 – 0 – 0 – 1
7) Washington – 0 – 11 – 0 – 11
Source Total – 35 – 21 – 2 – 58 {+1}

NOTE: One additional case was previously detected in a poultry worker in Colorado in 2022.

Additional cases meeting the Council of State and Territorial Epidemiologists (CSTE) probable case definition have been reported by states: 1 case with dairy cow exposure (CA), 3 cases with poultry exposure (WA). Confirmatory testing at CDC for these cases was negative.

This table is typically updated by 5 PM EST on Mondays (for cases confirmed by CDC on Friday, Saturday, or Sunday), Wednesdays (for cases confirmed by CDC on Monday or Tuesday), and Fridays (for cases confirmed by CDC on Wednesday and Thursday). Affected states may report cases more frequently.

(…)

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#aH5n1 #avianInfluenza #AVIANINFLUENZA #birdFlu #h5n1 #health #human #news #updates #USCDC #USA

#USA, #California: Current #H5N1 #Birdflu #Situation: 1 New #Human Case, Total = 32 (as of Nov. 4 ’24)

Source: Department of Health, https://www.cdph.ca.gov/Programs/CID/DCDC/Pages/Bird-Flu.aspx

{Excerpts}

Updated December 4, 2024​

​​​The current risk to the public remains low. ​​ No person-to-person spread of bird flu has been detected in California. People rarely get bird flu, but those who interact​ with infected dairy cows, poultry, or wildlife ​have a greater risk of infection.​​ Pasteurized milk and dairy products are safe to consume. Pasteurization inactivates the bird flu virus.​​

Human Cases in Califo​rnia​

​​​​​​​Confirmed Human Cases​: 32 {+1}

​These numbers were last updated on December 4, 2024.

California has 1 additional probable case with dairy cow exposure that meets the Council of State and Territorial Epidemiologists (CSTE) ​probable case definition (PDF)​. That case tested positive by a local lab and confirmatory testing at CDC was negative.​​

Confirmed human case summary during the 2024 outbreak, by exposure source

​Cattle​​​​:​ 31 {+1}
​Poultry: ​0
​Unkn​own:​ 1
​Total: ​32 {+1}

Contact Us: If you have any questions, comments or concerns, submit an inquiry.

If you’re a member of the media and have a question for CDPH, email Media@cdph.ca.gov​.​​​

(…)

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#aH5n1 #avianInfluenza #birdFlu #california #h5n1 #health #human #news #pandemic #updates #USA

#Colombia#Influenza A #H5 viruses of high pathogenicity (Inf. with) (non-poultry including wild birds) (2017-) – Immediate notification

Source: WOAH, https://wahis.woah.org/#/in-review/6085

Within the epidemiological surveillance carried out by the Colombian Agricultural Institute (ICA) aimed at identifying clinical signs consistent with avian influenza, an outbreak of Highly Pathogenic Avian Influenza (HPAI) was detected in the village of Capitancito, municipality of Acandí, Chocó. This outbreak concerns non-poultry birds in a backyard showing clinical signs characterized by unusual mortality. The National Veterinary System is carrying out epidemiological tracing and follow-up activities in the area of origin of the affected bird. As a control measure, stamping out of the birds present in the affected premises is being carried out. In addition, epidemiological surveillance is being reinforced in the surrounding area to detect additional cases and prevent the spread of the outbreak.

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#aH5n1 #avianInfluenza #captiveBirds #COLOMBIA #updates #WOAH

Controlling minor #outbreaks is necessary to #prepare for major #pandemics

Source: PLoS Biology, Perspective, https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.3002945

{Summary}

Ongoing influenza H5N1 outbreaks highlight the need for timely, scalable interventions that draw on lessons from COVID-19. In particular, successful pandemic preparedness requires early outbreak management, including effective responses targeting spillovers before there is evidence of human-to-human transmission.

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#aH5n1 #abstract #avianInfluenza #pandemicInfluenza #pandemicPreparedness #research

#USA, #California: ​State Secures Broad Voluntary Recall of Raw #Milk and #Cream to Protect #Consumers {from possible #H5N1 virus contamination}

Source: Department of Health, https://www.cdph.ca.gov/Programs/OPA/Pages/NR24-044.aspx

{Edited}

December 3, 2024

NR24-044​

Recall includes all Raw Farm, LLC raw milk and cream remaining on retail shelves; CDPH warns consumers against consuming any raw milk products from quarantined farm

CDPH

What You Need to Know: California has secured a broad, voluntary recall of all Raw Farm, LLC raw milk and cream products due to possible bird flu contamination. Californians are strongly encouraged not to consume any raw milk or cream products in their possession or still on store shelves. Pasteurized milk remains safe to drink.

Sacramento ​– Continuing its action to protect public health, the state has secured a broad, voluntary recall of all raw whole milk and cream products from Raw Farm, LLC that remain on retail shelves following multiple bird flu virus detections in the company’s milk and dairy in the past week. Raw Farm milk products have tested positive for bird flu at both retail and dairy storage and bottling sites in recent days.

Today’s expanded recall ensures that all sizes of Raw Farm milk and cream, produced between November 9 and November 27, are pulled from retail shelves. The affected lot numbers are 20241109 through 20241127, which includes the two lots recalled last week (November 27 and November 24​).

Customers should immediately return any remaining product to the retail point of purchase.

Public health officials identified the bird flu virus in retail products from Raw Farm, LLC last week. Additional testing by the California Department of Food and Agriculture (CDFA) of bulk milk storage and bottled products at Raw Farm’s bottling facility showed the presence of the bird flu virus. All milk tested by CDFA remained at the Raw Farm plant and was not released to consumers. As the disease investigation continues, Raw Farm is cooperating fully with CDPH and CDFA.

While this voluntary recall only applies to raw whole milk and cream, due to multiple bird flu detections in the company’s operation the California Department of Public Health (CDPH) urges consumers to avoid consuming any Raw Farm products for human consumption including raw milk, cream, cheese, and kefir, as well as raw milk pet food topper and pet food kefir marketed to pet owners.

In addition to the statewide voluntary recall, CDFA has placed the farm under quarantine, suspending any new distribution of its raw milk, cream, kefir, butter and cheese products produced on or after November 27.

No human bird flu cases associated with the product have been confirmed to date, and the state is working closely with federal and local partners to investigate the situation and better understand how it might impact consumers. California continues to monitor and respond to bird flu outbreaks in dairy cows and poultry. Bird flu virus levels have been demonstrated to be high in raw milk from infected cows, and sporadic human cases identified in workers in close contact with infected dairy cows and their milk indicate that raw milk is infectious to humans.

​Risks Associated with Raw Milk

Public health experts have long warned consumers against consuming raw milk or raw milk products due to elevated risks of foodborne illness. Outbreaks due to Salmonella, Listeria monocytogenes, toxin producing E. coli, Brucella, Campylobacter, and many other bacteria have all been reported related to consuming raw dairy products. Raw milk products are not pasteurized, a heating process that kills bacteria and viruses such as bird flu.

Pasteurized milk and pasteurized milk products are safe to consume because the heating process kills pathogens, including bird flu, that can cause illness.

Drinking or accidentally inhaling raw milk containing bird flu virus may lead to illness. In addition, touching your eyes, nose, or mouth with unwashed hands after touching raw milk with bird flu virus may also lead to infection. Symptoms of bird flu infection in humans include eye redness or discharge, cough, sore throat, runny or stuffy nose, diarrhea, vomiting, muscle or body aches, headaches, fatigue, trouble breathing and fever. Anyone who has consumed these specific products and is experiencing these symptoms, should immediately contact their health care provider or local health department.

Pet Safety and Raw Milk Pet Food Products

​CDPH advises consumers to avoid raw milk “pet food topper” and “pet food kefir” products marketed to pet owners. They should neither eat this food themselves nor feed it to their pets. Cats, dogs, and other animals may become sick with bird flu after drinking raw milk. Cats on infected dairy farms in multiple states have died from bird flu, most likely from drinking raw milk from infected cows. CDPH encourages pet owners to avoid feeding their pets raw pet food products in general, including raw milk-based products. To further limit risk to pets, pet owners should also keep their pets away from sick or dead birds.​​

California Regularly Tests Raw Milk

As part of the state’s bird flu response, testing of raw milk from dairies has been increased to help prevent raw milk consumers from getting the virus. Once bird flu was found in California dairy herds, the California Department of Food and Agriculture (CDFA) began regular testing of raw milk in bulk tanks. In response to these recent positive tests from two retail raw milk batches, CDFA followed up with immediate additional sampling and testing at Raw Farm.

Pasteurized Milk is Safe to Drink

Pasteurized milk is safe to drink. Pasteurization, one of the most significant scientific food safety discoveries in human history, is the process of heating milk to specific temperatures for a certain length of time to kill many microorganisms and enzymes that lead to spoilage and illness. Pasteurization kills the bird flu virus and other harmful germs that can be found in raw milk. CDPH advises consumers not to drink raw milk or eat raw milk products due to the risk of foodborne illnesses.

About Bird Flu

Since early October, California has reported 31 confirmed human cases of bird flu, 30 of whom had direct contact with infected dairy cows. No person-to-person spread of bird flu has been detected in California or the U.S. To date, all cases have reported mild symptoms (primarily eye infections), and none have been hospitalized. Because bird flu viruses can change and gain the ability to spread more easily between people, public health officials have provided preventive measures and are monitoring animal and human infections carefully.

Protecting Public Health

California continues to take swift and comprehensive action in response to the detection of bird flu in dairy cows across the Central Valley, demonstrating a strong commitment to public health and worker safety. While the overall risk to the public remains low, the state is prioritizing containment efforts, raising public awareness, and providing resources to those at higher risk. Key initiatives include the distribution of personal protective equipment (PPE), increased testing, and robust surveillance of infected areas.

Through coordinated efforts between CDPH, the California Department of Food and Agriculture, California Office of Emergency Services (CalOES), and other agencies, California is leading a cross-agency response that includes multilingual outreach to dairy and poultry workers, a targeted social media campaign to promote preventive practices, and media interviews to keep the public informed. Additionally, the state is ensuring that farm workers have access to additional doses of seasonal flu vaccine from the Centers for Disease Control and Prevention (CDC) to reduce concurrent flu risks.

Specifically, the state is:

— Working with local, state, and federal partners to monitor bird flu in farm animals and people who work closely with poultry and dairy cows. 
— Distributing protective gear to dairy farms and workers who have contact with infected dairy cows or raw milk to reduce the risk of getting bird flu. 
— Helping ensure individuals with symptoms of or exposure to bird flu have access to testing and treatment. 
— Conducting timely public education efforts​ to ensure those impacted have information about bird flu. 

How Bird Flu Spreads

— Touching the eyes, nose, or mouth with unwashed hands after contact with raw milk from an infected cow, or other contaminated items or surfaces. 
— Splashing raw milk from an infected cow into eyes, nose, or mouth.
— Drinking raw milk from a cow infected with bird flu virus. 

More Resources

— For the latest information on the state’s bird flu response, visit CDPH’s Bird Flu webpage​ and CDFA’s H5N1 Bird Flu Virus in Livestock site. 
— For information on the national bird flu response, see CDC’s Bird Flu Response Update​. 
— ​For work-related questions or complaints related to bird flu, contact the Cal/OSHA Call Center in English or Spanish at 1-833-579-0927. Employers can contact the California Occupational Health and Safety Division at 800-963-9424 for a free consultation to strengthen their illness and injury safety program. 
— ​Farmers should contact the California Department of Food and Agriculture’s bird flu hotline at 866-922-2473 if they suspect their animals are infected with bird flu.

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#aH5n1 #avianInfluenza #birdFlu #california #dairyProducts #food #foodSafety #health #milk #rawMilk #updates #USA

#Drosten on the #danger of #birdflu: “I fear that the time has now been missed”

Source: T-Online, https://www.t-online.de/gesundheit/aktuelles/id_100543766/virologe-drosten-zur-h5n1-gefahr-aus-der-corona-pandemie-nichts-gelernt-.html

{Excerpt, original article in German.}

The next epidemic is spreading: the number of bird flu infections is increasing in the USA. Experts such as virologist Drosten criticize the authorities’ actions.

T-Online.de

According to experts, it is doubtful that we have learned anything from the coronavirus pandemic. In many countries, pandemic plans have been dusted off or even created in the first place. But a current example shows that in cases of doubt, too little is still being done to stop the spread of dangerous pathogens as early as possible: the H5N1 bird flu viruses in US dairy farms. Since the first detections in March, according to the US Department of Agriculture, H5N1 cases have been recorded in hundreds of farms in many states.

(…)

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#aH5n1 #avianInfluenza #pandemicInfluenza #pandemicPreparedness

Structural Convergence and Water-Mediated Substrate Mimicry Enable Broad #Neuraminidase #Inhibition by #Human #Antibodies

Source: BioRxIV, https://www.biorxiv.org/content/10.1101/2024.11.27.625426v1?rss=1

Abstract
Influenza has been responsible for multiple global pandemics and seasonal epidemics and claimed millions of lives. The imminent threat of a panzootic outbreak of avian influenza H5N1 virus underscores the urgent need for pandemic preparedness and effective countermeasures, including monoclonal antibodies (mAbs). Here, we characterize human mAbs that target the highly conserved catalytic site of viral neuraminidase (NA), termed NCS mAbs, and the molecular basis of their broad specificity. Cross-reactive NA-specific B cells were isolated by using stabilized NA probes of non-circulating subtypes. We found that NCS mAbs recognized multiple NAs of influenza A as well as influenza B NAs and conferred prophylactic protections in mice against H1N1, H5N1, and influenza B viruses. Cryo-electron microscopy structures of two NCS mAbs revealed that they rely on structural mimicry of sialic acid, the substrate of NA, by coordinating not only amino acid side chains but also water molecules, enabling inhibition of NA activity across multiple influenza A and B viruses, including avian influenza H5N1 clade 2.3.4.4b viruses. Our results provide a molecular basis for the broad reactivity and inhibitory activity of NCS mAbs targeting the catalytic site of NA through substrate mimicry.

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#aH1n1 #aH5n1 #abstract #avianInfluenza #AVIANINFLUENZA #birdFlu #h5n1 #health #influenzaB #monoclonalAntibodies #news #research #SEASONALINFLUENZA

#Influenza A(#H5N1) Virus Clade 2.3.2.1a in #Traveler Returning to #Australia from #India, 2024

Source: Emerging Infectious Diseases Journal, https://wwwnc.cdc.gov/eid/article/31/1/24-1210_article

Abstract
We report highly pathogenic avian influenza A(H5N1) virus clade 2.3.2.1a in a child traveler returning to Australia from India. The virus was a previously unreported reassortant consisting of clade 2.3.2.1a, 2.3.4.4b, and wild bird low pathogenicity avian influenza gene segments. These findings highlight surveillance gaps in South Asia.

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#aH5n1 #abstract #australia #avianInfluenza #human #india #REASSORTANTSTRAIN #research

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

Source: WOAH, https://wahis.woah.org/#/in-review/6083

Five captive Eurasian Spoonbills in Grad Zagreb Region.

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#aH5n1 #avianInfluenza #captiveBirds #croatia #updates #WOAH

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

Source: WOAH, https://wahis.woah.org/#/in-review/6084

Wild birds of Anatidae Species in Schleswig-Holstein Region. The birds were tested as part of monitoring.

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#aH5n1 #avianInfluenza #germany #updates #WILDBIRDS #WOAH

#Pandemic #preparedness of effective #vaccines for the outbreak of newly #H5N1 highly pathogenic avian #influenza virus

Source: Virologica Sinica, https://www.sciencedirect.com/science/article/pii/S1995820X24001779?via%3Dihub

Highlights

— Analyzed the outbreak situation and viral characteristics of the newly H5N1 highly pathogenic avian influenza (HPAI) virus.

— The current approval and research and development of the H5N1 HPAI vaccines were summarized.

Proposed vaccine development approaches against newly H5N1 virus, e.g. adjuvanted vaccine, mRNA vaccine, multivalent vaccine.

— Discussed other prevention and control strategies, e.g. poultry vaccination, global surveillance and comprehensive testing.

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#aH5n1 #abstract #avianInfluenza #pandemicPreparedness #research #vaccines

#Influenza A(#H5N1) shedding in #air corresponds to #transmissibility in #mammals

Source: Nature Microbiology, https://www.nature.com/articles/s41564-024-01885-6

Abstract
An increase in spillover events of highly pathogenic avian influenza A(H5N1) viruses to mammals suggests selection of viruses that transmit well in mammals. Here we use air-sampling devices to continuously sample infectious influenza viruses expelled by experimentally infected ferrets. The resulting quantitative virus shedding kinetics data resembled ferret-to-ferret transmission studies and indicated that the absence of transmission observed for earlier A(H5N1) viruses was due to a lack of infectious virus shedding in the air, rather than the absence of necessary mammalian adaptation mutations. Whereas infectious human A(H1N1pdm) virus was efficiently shed in the air, infectious 2005 zoonotic and 2024 bovine A(H5N1) viruses were not detected in the air. By contrast, shedding of infectious virus was observed for 1 out of 4 ferrets infected with a 2022 European polecat A(H5N1) virus and a 2024 A(H5N1) virus isolated from a dairy farm worker.

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#aH5n1 #abstract #animalModels #avianInfluenza #AVIANINFLUENZA #birdFlu #dairyCow #h5n1 #health #news #pathogensAirborneTransmission #research

Polygenic #Determinants of #H5N1 #Adaptation to Bovine Cells

Source: BioRxIV, https://www.biorxiv.org/content/10.1101/2024.11.29.626120v1

Abstract
H5N1 avian influenza virus (lineage 2.3.4.4b, B3.13 genotype) has caused, unexpectedly, a large outbreak in dairy cattle in North America. It is critical to ascertain how this virus has specifically adapted to bovine cells and the molecular determinants of this process. Here, we focused on the contribution of the viral internal genomic segments of H5N1 B3.13 to bovine cells adaptation. We generated 45 reassortant viruses harbouring the haemagglutinin and neuraminidase from A/Puerto Rico/8/1934 and internal gene constellations from several influenza A viruses (IAV) or carrying segment swaps between distinct H5N1 strains. The recombinant B3.13 viruses displayed faster replication kinetics in bovine cells compared to other IAV. Importantly, multiple genomic segments of B3.13 viruses contribute to their faster replicative fitness. Further, recombinants with the B3.13 internal genes were less susceptible than ancestral 2.3.4.4b strain to the bovine IFN response. However, bovine (and human) MX1, a key restriction factor for avian IAV, restricted both ancestral 2.3.4.4b and B3.13 recombinant viruses. Interestingly, the latter escape restriction from human BTN3A3. Finally, recombinant B3.13 was virulent in mice unlike the ancestor 2.3.4.4b recombinant virus. Our results highlight the polygenic nature of influenza host range as multiple internal genes of B3.13 contribute to bovine adaptation.

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#aH5n1 #abstract #animalModels #avianInfluenza #AVIANINFLUENZA #birdFlu #dairyCow #h5n1 #health #news #research #viralPathogenesis

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