HomeMy WebLinkAbout2024_06_23 SSchumacher_Bird fluFrom:Stephen Schumacher
To:Board of Health
Cc:Allison Berry; Apple Martine; Veronica K. ShawSubject:Is a Bird Flu pandemic "inevitable"? Is Gain-of-Function Responsible for the Bird Flu Jump to Cows and Humans?Date:Sunday, June 23, 2024 9:44:08 PM
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https://x.com/RobertKennedyJr/status/1803792524160770533
By Robert F. Kennedy, Jr.June 20, 20204
Is a Bird Flu pandemic "inevitable"?
24 different pharmaceutical companies are racingto develop a bird flu vaccine-for cows! How manymore are working on a bird flu vaccine for humans?
Moderna's stock price has gone up 40% since birdflu moved into cows. The company is worth over$20 billion dollars more than it was 3 monthsago. The market knows that our government plansto use mRNA vaccines for emerging infections,regardless of whether the public wants them.They are already testing mRNA bird flu vaccines in cows.Let's go back a dozen years.
Fauci's NIAID paid scientists around the world todo gain-of-function experiments on bird flu tomake it transmissible to humans. Hundreds ofother scientists were so worried about thisbioengineered bird flu escaping that they got amoratorium placed on all gain-of-functionexperiments on bird flu and SARS, back in 2014.
What did Fauci do? We know he ignored themoratorium for SARS. Did he ignore it for birdflu also? Then he lifted the moratorium in 2017.
Fauci' NIAID has collected $690 million dollarsin royalties for vaccines for SARS-2, and anadditional $400 million in a legal settlementfrom Moderna. That is over a billion dollars.
But of course that is chicken feed compared towhat the government will spend on vaccines for SARS, or bird flu.
With so much money on the table, is itconceivable that someone might deliberatelyrelease a bioengineered bird flu? When this kindof gain-of-function research is going on,accidental or deliberate leaks are inevitable.
Maybe that's why former CDC Director Robert
Redfield said that a bird flu pandemic is "not a
matter of if, but when." Does he know something we do not?
We need to stop playing with fire. Myadministration will shut down thegain-of-function labs on Day 1, while we figureout what they are doing. We will end these lab-grown plagues for good.
---https://www.theepochtimes.com/health/bird-flu-jumps-twice-to-humans-how-concerned-we-should-be-5648232
Is Gain-of-Function Responsible for the Bird Flu Jump to Cows and Humans?
Certain types of bird flu viruses that typicallyspread among birds are now causing infections incows and humans in Western countries.
By<https://www.theepochtimes.com/expert/yuhong-dong-experts>YuhongDong, M.D., Ph.D. and<https://www.theepochtimes.com/expert/xiaoxu-sean-lin>Xiaoxu Sean Lin, Ph.D.5/29/2024
In the past six months, bird flu has surprised scientists at least twice.
Bird flu viruses have circulated mainly in birdsfor a long time. However, in early December 2023,an outbreak occurred in U.S. dairy cows, eventhough cattle are not<https://jamanetwork.com/journals/jama/fullarticle/2818724>typicallysusceptible to avian influenza A, the bird flu virus.
In late March, a<https://www.nejm.org/doi/full/10.1056/NEJMc2405371>U.S.dairy farm worker was infected by a H5N1 virus from a cow.
On May 22, a<https://www.cdc.gov/media/releases/2024/s0522-human-case-h5.html>secondhuman case of H5N1 infection was reported withprior exposure to infected dairy cows in Michigan.
On the same day in May,<https://www.reuters.com/world/asia-pacific/australia-finds-cases-avian-influenza-virus-farm-near-melbourne-2024-05-22/>anAustralian child was infected by an H7 strain,<https://www.cdc.gov/flu/avianflu/influenza-a-virus-subtypes.htm>anothersubtype<https://www.cdc.gov/flu/avianflu/influenza-a-virus-subtypes.htm>ofinfluenza A known to cause human infections.
Since bird flu infections in humans are rare,these incidents have raised significant concern among scientists.
Why is this happening, and how concerned should we be?
This article aims to avoid unnecessary fear abouta potential future pandemic. Instead, weencourage people to think rationally and makeappropriate adjustments for the future.
Rapid Spread in Birds
The history of the H5N1 virus family can betraced back to 1996 when it was first discoveredin a<https://pubmed.ncbi.nlm.nih.gov/12526344/>sickgoose in the Guangdong province of China.
H5N1 has evolved, resulting in different<https://www.ecdc.europa.eu/en/zoonotic-influenza/facts/factsheet-h5n1>geneticlineages (clades) as they mutate, similar to atypical pattern of behavior for RNA viruses suchas the ever-emerging COVID-19 variants. In 2013,the H5N1 clade 2.3.4.4b emerged. Since then, ithas spread rapidly to nearly<https://www.biorxiv.org/content/10.1101/2024.05.01.591751v1.full>100countries across Asia, Europe, Africa, andAmerica, becoming the<https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11083745/#B16-animals-14-01372>mostdominant clade and causing significant losses to the poultry industry.
In<https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9045435/>December2021, this particular clade 2.3.4.4b, was firstidentified in wild birds in the United States.
The clade quickly mixed with other circulatinginfluenza A viruses in wild birds in NorthAmerica. This resulted in viral<https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10227026/>reassortmentand recombination of genes and exhibiting diversecharacteristics. Many of these variants causesevere illnesses in mammals, significantly affecting their nervous system.
The Jump to Cows
The avian influenza virus, commonly called thebird flu virus, belongs to the flu virus family.Flu viruses have many natural hosts, includingducks, geese, swans, gulls, terns, waders, pigs, and horses.
Certain types of flu viruses typically infectspecific hosts and do not usually jump from one host to another.
There is a wide variety of bird flu viruses,
ranging from H1 to H19, but they have mostly
remained in birds and animals, rarely affecting humans.
This changed with the H5N1 clade 2.3.4.4b.
This clade became concerning because of theirfrequent spillover events. A<https://wwwnc.cdc.gov/eid/article/19/2/12-1694_article>spilloverevent occurs when a virus from one normal hostreservoir jumps into a new or different hostspecies, for example, jumping from a bird to a horse or cattle.
Since<https://www.biorxiv.org/content/10.1101/2024.05.01.591751v1.full>December2023, the highly pathogenic H5N1 clade 2.3.4.4bviruses have been reported to spread in dairycows in multiple U.S. states, according to the<https://www.aphis.usda.gov/livestock-poultry-disease/avian/avian-influenza/hpai-detections/livestock>U.S.Department of Agriculture (USDA) and<https://wwwnc.cdc.gov/eid/article/30/7/24-0508_article>Centersfor Disease Control.
From early this year, some cows have beenproducing less milk and eating less. It was laterconfirmed that the H5Nx clade 2.3.4.4b viruseswere present in both the cows' milk and nasalsamples. The<https://www.aphis.usda.gov/news/agency-announcements/federal-state-veterinary-public-health-agencies-share-update-hpai>USDAreported an outbreak in this clade in cows for the first time.
The December USDA preprint reveals that the sameviral strain was found in dairy cows that have noknown connection to the infected herds. This
suggests that the transmission in cows hasalready started quietly, and asymptomatic cowslikely contributed to the rapid spread of the virus.
As of May 28, there were<https://www.cdc.gov/flu/avianflu/avian-flu-summary.htm>67herds infected by the H5N1 virus in nine states.Despite the low number of infected herds, thiscould indicate that it is no longer just aspillover event, but rather a significantexpansion of host tropism. The concern is when alarge-scale outbreak might occur.
Furthermore, as dairy cows often live in closeproximity to humans, infections in cows may also impact human health.
The Likely Jump to Humans
Although bird flu infections in humans have been
<https://www.cdc.gov/flu/avianflu/virus-transmission.htm>rare, they can happen.
In the past 20 years, there have been sporadichuman infections with the H5N1 virus. There havebeen<https://cdn.who.int/media/docs/default-source/influenza/h5n1-human-case-cumulative-table/cumulative-number-of-confirmed-human-cases-for-avian-influenza-a%28h5n1%29-reported-to-who--2003-2024.pdf?sfvrsn=796d8c4f_3&download=true>888infected patients, resulting in 463 deathsreported across 23 countries. The majority ofcases have occurred in Egypt, Indonesia, andVietnam. These cases have resulted in acumulative case fatality rate of more than 50percent, based on data collected by the World Health Organization.
Since these cases are mostly scattered throughoutAsia, they haven't received much public attentionin Western countries until recently.
In April 2022, a case was confirmed<https://www.cdc.gov/media/releases/2022/s0428-avian-flu.html>ina Colorado poultry worker who has sincerecovered. This was the first known case of H5N1infection transmitted from poultry to a human in the United States.
The second human case in the United States didn'toccur until late March.<https://www.nejm.org/doi/full/10.1056/NEJMc2405371>Adairy farm worker in Texas showed symptoms ofhemorrhagic conjunctivitis in both eyes and wasconfirmed to be infected by the H5N1 clade2.3.4.4b. He had no respiratory symptoms and fully recovered within a few days.
However, this person reported no contact withsick or dead birds but had close exposure to sickdairy cows. The cows showed decreased milkproduction, reduced appetite, fever, anddehydration, suggesting H5N1 infection.
This was the first report in the United States ofthe highly pathogenic avian influenza H5N1 virussuspected of transmitting from a mammalian animal species to a human.
These cases have alerted scientists, as theysuggest that the virus may have acquired theability to spread between mammals and potentially infect humans.
If a highly pathogenic H5N1 virus were to develop
the ability to spread easily among humans,
including through human-to-human transmission, itcould have a significant impact on the humanpopulation, given the high mortality rate observed in previous cases.
Since these are the only two confirmed U.S. casesof cow-to-human transmission, the full extent ofsimilar infections and the mortality rate remain unknown.
The spillover from one species to anothertypically happens naturally through the foodchain. For instance, it can happen when infectedbirds are eaten by another species. These eventsgenerally occur on a small scale, unlike thewidespread occurrences seen in U.S. cattle.
What caused the recent jump to cows from anotherspecies? Was it a natural, random event as in thepast, or were other factors involved?
Gained the Ability to Spread via Aerosols
The original avian H5N1 viruses were not easily transmissible between mammals.
About a decade ago, two virologists,<https://pubmed.ncbi.nlm.nih.gov/22722205/>YoshihiroKawaoka from the University of Wisconsin inMadison and<https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4810786/>RonFouchier of Erasmus Medical Center in the
Netherlands, alarmed the world by conductinghigh-risk gain-of-function studies on H5N1.
The process was complex. For example, a mutantH5N1 virus was created carrying the specific genemutation PB2 E627K. It was then passed throughferrets 10 times. After gaining a total of fivemutations, the mutant H5N1 virus gained theability to be transmitted via aerosols or respiratory droplets.
These mutations had only been found in nature,but never all within the same strain. Moreover,their<https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3838911/>labmanipulatio<https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3838911/>nand enhanced ability to transmit via aerosol hasresulted in pandemic potential.
In 2011, Paul Keim, a microbial geneticist who
chaired the U.S. National Science Advisory Board
for Biosecurity (NSABB), expressed concern afterreviewing their publications. "I can't think ofanother pathogenic organism that is as scary asthis one," he told<https://www.science.org/content/article/scientists-brace-media-storm-around-controversial-flu-studies?adobe_mc=MCMID%3D55130761107504242354096334758919231102%7CMCORGID%3D242B6472541199F70A4C98A6%2540AdobeOrg%7CTS%3D1715823328>Science.Having worked on anthrax for many years, headded, "I don't think that anthrax is scary at all compared to this."
Publishing these key mutations enables others toreplicate the work in their own labs and marksthe beginning of the unsettling H5N1 narrative.
The H5N1 clade 2.3.4.4b was<https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11083745/#B16-animals-14-01372>firstdetected in 2013.
Further Manipulation in a Chinese Lab
On April 1, 2021, a<https://www.ars.usda.gov/research/project/?accnNo=439621>three-party<https://www.ars.usda.gov/research/project/?accnNo=439621>projectwas initiated between the United States, the UK,and China that included the USDA, the U.S.National Poultry Research Center, the SoutheastPoultry Research Laboratory (SEPRL) in Georgia,the Chinese Academy of Sciences (CAS), and the Roslin Institute in the UK.
The USDA is sponsoring a grant of<https://cris.nifa.usda.gov/cgi-bin/starfinder/0?path=fastlink1.txt&id=anon&pass=&search=R=90432&format=WEBLINK>$1million for this project. The SEPRL and RoslinInstitute provide expertise in avian immunologygenomics and viral transcriptomics analysis.
The actual experiments are conducted in China'sCAS lab. There might be a specific reason for choosing this location.
The project, as we'll explain later, is also a gain-of-function (GOF) study.
GOF studies on the bird flu virus have triggeredbroad criticism by the U.S. scientific communitysince 2011. Richard Ebright, a molecularbiologist and laboratory director at the WaksmanInstitute of Microbiology, also told Science,
"This work should never have been done." From a
biosafety perspective, scientists have expressed
concern that a new virus generated through
research could escape from the lab or thatbioterrorists could leverage the publishedresults into a bioweapon for malignant purposes.
In the United States, gain-of-functionexperiments involving influenza, Middle Eastrespiratory syndrome coronavirus, and severeacute respiratory syndrome coronavirus were<https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7128689/>bannedfrom October 2014 through December 2017. Themoratorium was lifted by the National Institutesof Health (NIH) on Dec. 19, 2017.
Chinese labs often have sufficient technicalcapacity but face a<https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7148667/>majorchallenge due to relatively loose biosecurity regulations.Former CDC director, Dr. Robert Redfield,<https://www.theepochtimes.com/health/ex-cdc-director-warns-gain-of-function-research-on-bird-flu-could-spark-great-pandemic-5649152>recentlystate<https://www.theepochtimes.com/health/ex-cdc-director-warns-gain-of-function-research-on-bird-flu-could-spark-great-pandemic-5649152>d,"Bird flu, I think, is going to be the cause of agreat pandemicwhere they are teaching theseviruses how to be more infectious for humans."
A Severe, Rapidly Spreading Virus
Chinese scientists are not opposed to doing riskygain-of-function studies on bird flu viruses.
For example, in a study published in Science inMay 2013, scientists led by Chen Hualan at HarbinVeterinary Research Institute in Harbin, China,<https://www.science.org/doi/10.1126/science.1229455?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%20%200pubmed>combinedthe highly lethal but not easily transmissibleH5N1 virus with the highly contagious<https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2850175/#:%7E:text=The%202009%20H1N1%20virus%20contains,to%20H1N1%20strains%20before%201957.>H1N1swine flu strain, which infected millions of people in 2009.
<https://www.ars.usda.gov/research/project/?accnNo=440252>Atleast three aspects of the three-partycollaborative project study design stronglyindicate its gain-of-function nature. However,these may be difficult to discern without reading between the lines.
One significant issue is the experimentalapproach known as "serial passage." The processof serial passage research is
<https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7435492/>widely
acknowledged by scientists as a tool for gain-of-function studies.
Serial passage involves growing and reproducingthe virus from one cell to another or from oneanimal to another. These studies have high risksof generating mutations that can lead to greatertransmissibility, pathogenicity, and zoonotictransmission. The more potent mutants can be selected for the next passage.
As written in their proposal, CAS scientists areresponsible for measuring "fitness," whichindicates the outcome of a viralinfectionwhether it develops faster or slowerand whether it results in a severe or mildillness. Samples are collected before and aftereach round of passages to identify patterns oftransmission and pathogenicity. This increasesthe likelihood of creating mutant H5N1 strainsthat can cause more severe diseases with faster transmission.
The second clue is linked to the animal modelsthey carefully selected to reproduce thevirusmallard ducks, Chinese geese, and Japanese quail.
The mallard duck is the most abundant migratoryand wide-ranging duck on Earth and can crossbreedwith 63 other species. It is an asymptomaticcarrier harboring many bird flu viruses,potentially allowing more mutated viruses to recombine.
Flu viruses are large, single-stranded RNAviruses comprising an<https://www.pnas.org/doi/full/10.1073/pnas.1206069109#:%7E:text=Influenza%20A%20virus%20possesses%20a,particles%20has%20not%20been%20determined.>eight-segmentedgenome. This unique feature of the virus genomeimplies that it is easy to reassort to oneanother, resulting in different combinations ofgenomes, especially when given a perfectcondition of many different types of viruses residing in one host.
Furthermore, the Japanese quail has a dualexpression of two bird flu virus receptors onboth avian and mammalian species. It is such anideal host that after a series of passage trials,people can identify those strains that are moreadaptive to mammalian receptors but not bird receptors.
Therefore, this study design favors the selection
of a mutated H5N1 virus that has enhanced tropism
for mammalian hosts with a higher pathogenicity or transmissibility.
This is a technologically well-designed studysetting to achieve the gain-of-function purpose,in which the study objective appears to be aboutenhanced surveillance, monitoring, fitness, and vaccine studies.
In addition, this study plans to use live virusesto challenge mallard ducks with low-pathogenicbird flu viruses first, followed by a high-pathogenic virus.
Because the bird flu virus is highly prone torecombination, a genome reassortment among high-and low-pathogenic bird flu viruses couldgenerate new recombinant influenza viruses withunpredictable host tropism or pathogenicity.
Therefore, this creates an even higher potentialof generating new gain-of-function mutants.Since 2021, the bird flu virus H5N1 of clade2.3.4.4b has had an<https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10227026/>explosivegeographic expansion among wild birds anddomestic poultry across Asia, Europe, and Africa,and spread to America at the end of 2021.
Response to Criticism
There has been longstanding criticism ofgain-of-function research. Several members of the
U.S. Congress have also<https://blog.whitecoatwaste.org/wp-content/uploads/2024/04/udsa-avian-flu-letter.pdf>expressedserious concern about collaborating with the Chinese on bird flu research.
"We are disturbed by recent reports about theU.S. Department of Agriculture's (USDA)collaboration with the Chinese Communist Party(CCP)-linked Chinese Academy of Sciences (CAS) onbird flu research," they wrote in an April 12 letter.
"This research, funded by American taxpayers,could potentially generate dangerous newlab-created virus strains that threaten ournational security and public health," they added.
When interviewed by the Science journal inFebruary, the lead investigator<https://www.science.org/content/article/lawmaker-raises-new-flap-over-u-s-funded-virology-research-critics-call-risky>denied
that they planned to do gain-of-function studies.
However,
<https://www.ars.usda.gov/research/project/?accnNo=440252>theexperimental approach includes "in vivo passageof viruses through mallard ducks and Chinesegoose species to predict evolution in natural hosts."
The lead scientist at CAS involved in this study,Wenjun Liu, emphasized that the Chinesegovernment has strict regulations for lab safety.<https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7435492/>However,this argument is far from convincing since even abiosafety level 4 labthe highest safetylevelcan have serious safety compliance issues,as demonstrated with the Wuhan Institute of Virology and COVID-19.
The<https://www.theepochtimes.com/us/biden-administration-suspends-funding-for-scientist-linked-to-wuhan-laboratory-5655203>recentsuspension of funding for scientist Peter Daszak,president of EcoHealth Alliance, sends a clearsignal that people distrust virological studieslinked to Chinese government-controlled labs.
Increased Pathogenicity
The pathogenicity of H5N1 in animals has increased.
In a 2023 study published in<https://www.cell.com/iscience/fulltext/S2589-0042%2823%2901907-7?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS2589004223019077%3Fshowall%3Dtrue>Cell,researchers at the University of Pittsburgh andthe Vaccine Research Center of the NIH, usedtheir existing model of cynomolgus macaques totest the effectiveness of the H5N1 vaccine.
In this study, an inhaled aerosol dose of 5.1log10 plaque-forming units (PFU) caused a strongfever and acute respiratory disease in four outof six macaques, resulting in their deaths. PFUis a method of measuring the amount of the virus.
In comparison, in studies conducted from 2001 to2014 with cynomolgus macaques, when these monkeyswere given high doses of H5N1 (6.5-7.8 log10 PFU)through various routes (nose, throat, mouth, andeyes), they usually developed mild illness, and
only 2 out of 49 monkeys died from the infection, based on previous reports.
Compared to the studies done 10 to 23 years ago,
a much lower dose used in the 2023 study caused amuch higher percentage (half) of the monkeys'deaths. This indicates that the pathogenicity ofthe H5N1 virus has dramatically increased.
History Repeated?
While we retrospectively reviewed the timing ofthe GOF studies in 2012 and 2021 and theoutbreaks of H5N1 bird flu viruses in birds andmammals in 2013 and 2021, it is clear that thereis a close temporal relationship between them.
This research on the bird flu viruses and currentoutbreaks in birds and cows should also remind usof the fiercely debated origin of SARS-CoV-2.
A widely discussed, evidence-based viewpoint onthe origin of the SARS-CoV-2 virus suggests thatbat-derived coronaviruses, previously harmless tohumans, gained the ability to infect humansthrough <https://www.nature.com/articles/nm.3985>lab manipulation.
It's particularly important to consider thecurrent focus of scientific research afterexperiencing an unprecedented, challenging perioddue to COVID-19. Some Chinesegovernment-controlled labs are still creatingmore dangerous viruses and enabling them to
spread on a large scale in the name of pandemicpreparedness. This raises the question of whetherthey are truly helping people or creating more diseases.
These alarming facts and circumstances shouldprompt immediate, thorough investigations intoChinese labs and their potential connection to the H5N1 bird flu outbreak.
In the pursuit of advancing science andresearching more effective ways to protectpeople, such as developing vaccines, theunderlying driving force behind such endeavors isoften technological competition. However,scientists may have created more problems than solutions for humanity.
In many health articles from<https://www.theepochtimes.com/health?ea_src=frontpage&ea_med=header-navbar-10>The
Epoch Times, we emphasize that the best way to
prevent a pandemic or viral infection is to focus
on improving our health. This includes
maintaining a<https://www.theepochtimes.com/health/building-resilience-nurturing-your-body-for-a-post-covid-pandemic-future-5244490>healthylifestyle, enhancing our<https://www.theepochtimes.com/health/the-miraculous-immune-system-5523119>naturalimmunity, and preserving our<https://www.theepochtimes.com/health/the-secret-healing-power-of-a-treatment-hidden-for-200-years-5626059>naturalhealing abilities.
Editing the virus to enhance its transmissibilityand pathogenicity, and researching its pandemicpotential, only fuels more fear, rather than resolving the issue.
Ironically, some modern technology can have anextensive negative impact on society. The abilityof scientists to conduct GOF research does not justify its necessity.
It's time for people to wake up.
More About Bird Flu Viruses
There are four types of flu viruses: A, B, C, andD. Based on our current knowledge, only type Acan cause global pandemics. A pandemic can occurwhen an influenza virus has the ability to createlong-lasting<https://www.who.int/en/news-room/fact-sheets/detail/influenza-%28avian-and-other-zoonotic%29>human-to-humantransmission in a population with limitedimmunity against the virus. In history, threetype A flu viruses have triggered humanpandemics: H1N1 (1918), H2N2 (1957), and H3N2 (1968).
Influenza A viruses are classified into dozens ofsubtypes according to two types of glycoproteins on the surface of the virus.
The first glycoprotein,<https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5536029/#:%7E:text=The%20neuraminidase%2C%20or%20the%20receptor,%2C%20host%20adaptation%2C%20and%20pathogenicity.>hemagglutinin(H), allows the virus to bind to a celluarsurface receptor known as sialic acid and enterthe cell. Its name comes from its ability tocause red blood cells to clump together intomasses. The second one, neuraminidase (N), is areceptor-destroying protein and enzyme thatcleaves the glycosidic bonds of the neuraminic
acid, which helps release new viral particles
from infected cells. The balance between the H
and N function has potential implications for
transmission, host adaptation, and pathogenicity between species.
A total of 19 H proteins(H1-<https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10308872/>H19)and 11 N proteins (N1-N11) have been<https://www.cdc.gov/flu/about/viruses/types.htm>identified.Different combinations of H and N can be used toname a flu virus. H5N1 has a type 5 H and a type 1 N, so its name is H5N1.
The "H5Nx" nomenclature indicates differentneuraminidase types (such as N1, N2, N6, N8) are paired with the H5 protein.
A "clade" is like a branch on a family tree. In avirus family, a clade refers to a group ofviruses from a common ancestor with similarcharacteristics. Clade 2.3.4.4b<https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9863098/>includesvarious viruses from H5N1, H5N2, H5N5, H5N6, and H5N8.
Five subtypes of avian influenza A viruses, H5,H6, H7, H9, and H10 are known to have caused human infections.
Bird flu viruses are classified as either low orhighly pathogenic avian influenza based on the disease severity they trigger.
The H5 and H7 subtypes are highly pathogenic.Specifically, A(H5N1) and A(H7N9) viruses havecaused most of the avian influenza A viral infections reported in people.
HPAI A(H5N6) and LPAI A(H9N2) viruses have alsocaused human infections in recent years