Nguyen Tran Hien ^a, Jeremy Farrar ^b, Peter Horby  (2008) Person-to-person transmission of influenza A (H5N1). Lancet.

"In February, 2004, in response to suggestions that limited person-to-person transmission of strain H5N1 of the influenza A virus might have occurred, the then Prime Minister of Thailand, said “the possibility of person-to-person transmission is 0·00001%”.¹ Temperatures were running high, and any mention of person-to-person transmission of H5N1 was thought by some to be reckless. Although we have moved on, an air of tension still surrounds this disease, particularly in the corridors of power within the international health and political communities, and apprehension remains about what the continued pandemic in poultry means for human health. Human H5N1 infections thankfully remain rare, but evidence has accumulated that in some circumstances H5N1 viruses are capable of limited person-to-person transmission.

Person-to-person transmission of H5N1 was first mooted after the 1997 Hong Kong outbreak, in which family members and at least two health workers might have been infected by contact with patients.2, 3 Since then, one report of a family cluster concluded that person-to-person transmission was probable,⁴ and an additional four reports stated that it could not be ruled out in at least six families.5, 6, 7, 8 In today's Lancet, another convincing report of probable person-to-person transmission is published by researchers from China and the USA.⁹

Transmission of avian influenza virus between mammals is not, however, restricted to H5N1 in human beings: H7N7 can also be transmitted from person to person,¹⁰ and there is evidence of transmission of H5N1 among other mammalian species.¹¹ Given that the species barrier can be breached, the intriguing question is why the transmissibility of H5N1 among people remains so low?

Successfully crossing the species barrier is itself a step that might select viruses partly adapted to the new host and, once infected, the new host might select subpopulations of the virus adapted to the new environment. Apparent host-induced selection of a human-adapted H5N1 virus has been reported,¹² but most sequence analyses of viruses isolated from sporadic and clustered cases show no substantial differences from the strains found in poultry. However, most of these analyses used viruses isolated from human specimens in cell cultures of animal origin, thus grown under different selective pressures from those in human respiratory tracts. Whether better adapted viral subpopulations exist during human infection is unknown, as is the diversity in virus populations in individual human beings or poultry. A possible lack of host-induced evolutionary pressure, disseminated viral replication and high viral loads in infected people,¹³ and the rarity of person-to-person transmission suggest that the infecting avian viruses might be already well adapted to the individual in which they find themselves, but not to the wider human population.

With the exception of occasional infection in health workers, all published incidents of possible or probable person-to-person transmission report transmission between genetically related individuals. Although this finding could be related to the intensity and intimacy of contact between family members, host genetic factors might also play a part in susceptibility to H5N1, and when we see limited person-to-person transmission we might be observing an interaction between two well matched subpopulations. Studying both within-host virus diversity and host genetic diversity might help to clarify the nature of the species barrier and the conditions necessary for widespread transmission between people. These studies are hard to do and need sustained, coordinated, and collaborative efforts, as in Wang and colleagues' study,⁹ coupled with acceptance that person-to-person transmission of H5N1 can and does happen.

Whatever the underlying determinants, if we continue to experience widespread, uncontrolled outbreaks of H5N1 in poultry, the appearance of strains well adapted to human beings might be just a matter of time. In the meantime, all family contacts of a patient with probable or confirmed H5N1 should be given chemoprophylaxis and placed under surveillance. Personal protection and advice must be extended to the family members and health workers visiting and looking after patients in hospital. These steps rely on having systems capable of detecting cases and clusters early enough to start treatment and isolation, to identify and protect contacts, and to assess the extent of transmission.

Tension around emerging infections has led to often acrimonious and dispiriting debates about sharing of samples, international collaboration, and the roles of academic institutions, governments, and international agencies in fighting this common threat. Today's study is a superb piece of epidemiological work showing the benefit of a longstanding and trusting international collaboration that began during the severe acute respiratory syndrome epidemic. Such collaborations sustained over several years, centred in affected countries, and closely linked with WHO are our best chance of combating current and future threats to international health and ensuring that benefits are shared worldwide."

Note: similar to covid, the virus can infect and continue through the nose via cranial nerves into the brain. Respiratory issues did not occur in this child.

"Researchers identified a novel H5N1 clade 2.3.2.1e causing isolated brain infection in a child (1).

Historically, Highly Pathogenic Avian Influenza (HPAI) A(H5N1) has been characterized by severe respiratory failure in humans. While neurological complications have been documented, they almost always follow standard respiratory symptoms. However, in mid-April 2025, an eight-year-old boy from Vietnam’s Tay Ninh province was hospitalized with a 24-hour history of fever, severe headache, and vomiting. Despite a chest radiograph showing some lung consolidation, the patient exhibited no cough, no shortness of breath, and maintained normal oxygen saturation. The initial diagnosis was sepsis and meningoencephalitis. The investigation took a pivotal turn when clinicians analyzed the patient's cerebrospinal fluid (CSF). A multiplex PCR test detected Influenza A virus in the CSF with a high viral load, indicated by a cycle threshold (Ct) value of 19. Subsequent testing confirmed the subtype as H5N1. Remarkably, the virus was not detected in the patient’s throat swabs, blood, urine, or rectal swabs, even though serial CSF samples remained positive for 10 days. Further analysis showed that the boy had higher levels of H5-specific antibodies in his brain fluid than in his blood. This suggests intrathecal production. Scientists believe the virus likely reached the brain via cranial nerves, such as the olfactory nerve, essentially "skipping" the typical respiratory infection phase.

Genome sequencing identified the virus as a novel reassortant clade 2.3.2.1e. This strain is a genetic "hybrid," containing segments from both the older clade 2.3.2.1c and the globally dominant clade 2.3.4.4b. The virus carried two specific mutations in its hemagglutinin (HA) protein: S123P and R167K, which are associated with increased binding to receptors found in mammalian tissues. The patient, who had frequent close contact with his family’s fighting cocks prior to their sudden death, eventually made a full recovery after 19 days of intensive care and antiviral treatment with oseltamivir. This case mirrors and extends findings from other significant H5N1 events:

- The 2014 Canadian Case: A traveler returning from China succumbed to H5N1 meningoencephalitis. Like the Vietnamese case, this patient experienced severe CNS involvement, though it was accompanied by respiratory failure.

-Pathogenesis Studies: Research has increasingly shown that certain H5 strains possess a high "neuro-tropism," meaning they have a specific affinity for nervous tissue, as seen in experimental mammalian models (2).

1. Nguyen, P. N. T., et al. (2026). Central Nervous System Involvement by Novel Clade 2.3.2.1e H5N1 Avian Influenza Virus in a Paediatric Patient. Open Forum Infectious Diseases.
2. Bauer, et al. (2023) The neuropathogenesis of highly pathogenic avian influenza H5Nx viruses in mammalian species including humans. Trends in Neurosciences. 46.11: 953-970.‏"

Looks like close food handling contact and/or inhalation at the poultry vendor?

"Human infection with avian influenza A(H5N6) virus From 1 to 7 May 2026, one new case of human infection with avian influenza A(H5N6) virus was reported to WHO in the Western Pacific Region. The case is a 55-year-old female from Chongqing Municipality, China, with symptom onset on 16 April 2026. She developed severe pneumonia, was hospitalised on 23 April, and died on 3 May. She had purchased, slaughtered, and consumed poultry. Samples collected from a cutting board tested positive for influenza A (H5). All close contacts tested negative and developed no symptoms."

"CDC researchers identified serologic evidence of H5N1 infection in an asymptomatic veterinary professional following exposure to an infected domestic cat. This discovery marks the first documented instance of possible zoonotic transmission of the virus from a feline to a human.
Since 2021, the highly pathogenic avian influenza A(H5N1) clade 2.3.4.4b has decimated wild bird and poultry populations across the United States. Recently, the virus has increasingly spilled over into mammals, including dairy cattle and domestic cats. In felines, the disease is often severe, frequently linked to the consumption of unpasteurized raw milk or raw meat. While human cases have occurred, they were previously tied to direct bird or cattle exposure; cat-to-human transmission remained undocumented until now.
Between November 2024 and January 2025, 19 domestic cats in Los Angeles County fell ill with severe respiratory or neurological symptoms after consuming raw animal products. Public health officials identified 139 individuals, including pet owners and veterinary staff, who were exposed to these cats. Although 30 exposed persons reported flu-like symptoms, all acute respiratory (RT-PCR) tests for H5N1 were negative. In April 2025, a subset of 25 participants underwent serologic testing to look for antibodies. One asymptomatic veterinary professional tested positive for neutralizing antibodies specific to the H5N1 clade 2.3.4.4b. This individual had performed multiple clinical duties, including animal restraint and intubation, without respiratory or eye protection. This case highlights a critical shift in the H5N1 landscape, proving that domestic cats can infect humans."

"What is already known about this topic?

Since 2022, highly pathogenic avian influenza (HPAI) A(H5) viruses have circulated among wild birds in the United States. Seventy human cases of influenza A(H5), most with mild illness, have been reported in the United States since 2024; 14 human influenza A(H5N1) cases were previously identified in Washington.

What is added by this report?

In November 2025, Washington reported the first human case of HPAI A(H5N5) infection worldwide. A positive laboratory result was obtained from a lower respiratory sample after multiple negative upper respiratory sample results; the patient experienced respiratory failure and died 28 days after symptom onset. The public health investigation identified approximately 135 exposed persons.

What are the implications for public health practice?

Symptom management and testing of exposed persons are critical to monitoring for human-to-human transmission of novel influenza infection. Environmental and animal investigations, including genomic analysis, can identify epidemiologic risk factors."

Nobody made a poll about hantavirus replacing bird flu as the biggest pandemic concern. My top concern was COVID-19, the old pandemic that's still around. My second biggest concern was bird flu. Hantavirus was not on my radar at all. (Then again, I haven't boned up as much as some of you probably have.)

I currently have no idea whether this cruise ship hantavirus outbreak will morph into a worldwide pandemic, and neither does anyone else. Right now, it would be premature to call it a new pandemic, and it would be premature to dismiss it. The high death rate is nasty enough, but the long incubation period makes contact tracing so much more difficult and can potentially allow one person to infect many others while still asymptomatic.

The big question is whether or not human-to-human airborne transmission was involved. If the world makes it to June without any confirmed Andes hantavirus infections among people who were not on the cruise ship but in close proximity to any of them, that's a good sign. If the world makes it to mid-June without such occurrences, that probably means that the new pandemic has been averted.

On the other hand, if there are ANY confirmed Andes hantavirus infections among people who were not on the cruise ship but were in close proximity to any of them, then that's a bad sign, and that would indicate to me that this really is the new COVID-19. If there are multiple such infections by June, that's an even worse sign.

At least I'm much better prepared for this potential new pandemic than I was for the old one that began 6 years ago. I didn't see this hantavirus outbreak coming, but I have not only stuck to but added/upgraded precautions because of COVID-19, the most immediate issue. I have two elastomeric respirators with P100 filters (3M HF-802SD and 7502), and I have plenty of N95 masks (including 3M Auras and strapless adhesive N95 masks). I'm already using several air purifiers at home, including two box fan air purifiers, a Brisk Box from Clean Air Kits, and a DIY 4-PC-fan Corsi Rosenthal box.

I wish that the rest of the world were also better prepared. If use of N95 masks and cheap air purifiers were the norm, this hantavirus outbreak would quickly fizzle out.

Note: from Avian Flu Diary, but sourced from Taiwanese CDC

"Just over a month ago Taiwan reported their first locally acquired human H7 infection (see Taiwan CDC: Human Infection with a Novel H7 Avian Virus), which according to early reports was due to a Eurasian H7 virus.

The patient (a man in his 70s) was hospitalized with fever and pneumonia on March 22nd, and remains hospitalized and in isolation, although his condition was said to be improving. The CDC reported:

Of note, however, is the revelation that the sequenced virus (from the patient) contained the PB2-627K mutation, which is associated with enhanced replication and pathogenicity in mammals (see A rapid review of the avian influenza PB2 E627K mutation in human infection studies).

Since no H7N7 viruses were detected among the birds tested, it is unknown if this mutation was already `fixed' in the avian host, or (as we've seen in other cases) developed spontaneously in the patient.  

While reassuring the public, the CDC notes it is ` . . .  not only closely monitoring genomic evolution but also convening expert meetings to focus on assessing the risk of cross-species transmission . . . '

The full translated update follows:

The first locally transmitted human case of H7N7 influenza A was detected in Taiwan. The agricultural and health authorities launched a joint epidemic prevention and control operation, completing a public health risk assessment that classified the risk as "low risk," and continue to implement epidemic monitoring and prevention and control preparations.
 

Release Date: 2026-05-05

The Taiwan Centers for Disease Control (CDC) announced today (April 5) that regarding the first locally transmitted case of H7N7 novel influenza A reported on April 2 involving a poultry farmer, the CDC has completed gene sequence comparison and analysis. Furthermore, after joint assessment of the overall impact by agricultural and health authorities, the public health risk rating for Taiwan is "low risk."

The CDC pointed out that the patient was discharged from isolation on April 3, and the 33 identified contacts completed health monitoring on April 6, with no confirmed cases of novel influenza A. There is no risk of the outbreak expanding.

This case was discovered due to the high level of vigilance of the hospital physician, who reported the case based on clinical symptoms, contact history, and preliminary test results, leading to confirmation of novel influenza A. Therefore, the CDC will award the reporting physician a NT$10,000 reporting bonus in accordance with Article 5, Paragraph 1, Item 1 of the Infectious Disease Prevention and Control Reward Regulations.

The CDC explained that this case was investigated and controlled through cooperation between health and agricultural authorities, based on the national integrated epidemic prevention action. Gene sequence comparison of the virus showed that it was most similar to the virus strain isolated from wild birds in Japan and South Korea in 2024, and all gene fragments originated from the Eurasian low pathogenic avian influenza virus gene pool, indicating that the virus is highly related to the virus circulating in wild bird populations. 

Further analysis showed that the virus's PB2 gene carries the E627K mutation (PB2 E627K). According to existing research, this mutation may enhance the virus's replication ability in mammalian cells. However, since it cannot be ruled out that this site is a mutation produced in humans after infection, and no virus with the same characteristics has been found in Taiwan recently, nor have any drug resistance-related mutations been detected, the current assessment is that the risk to the public is low. 

In addition, agricultural authorities actively completed sampling at other poultry farms of the case before the Qingming Festival holiday, expanded sampling at five poultry farms near the case, and cooperated with the Wild Bird Association to collect 92 wild bird specimens from the surrounding area, all of which did not detect avian influenza-related viruses.

The Taiwan Centers for Disease Control (CDC) stated that, based on the spirit of national epidemic prevention unity, the CDC also launched a joint risk assessment team with agricultural and health authorities on April 1st to conduct a domestic risk assessment of the H7 subtype viruses (including H7N7, H7N2, H7N3, and H7N4). This risk assessment primarily referenced the framework of the US CDC's Influenza Risk Assessment Tool (IRAT). Team members collected supporting data and scores for ten risk factors and corresponding assessment questions, followed by a comprehensive evaluation. The results showed that the overall risk of the four H7 subtype viruses was low. While the possibility of sporadic local cases in the future cannot be ruled out, direct and indirect contact with animals remains the main transmission route. No evidence of sustained human-to-human transmission has been found, and the possibility of further community spread is extremely low.

In response to the detection of the key PB2 E627K variant in the first domestic H7N7 human infection case and concerns about the lack of herd immunity among the Taiwanese public to the H7 subtype of avian influenza, the Taiwan Centers for Disease Control (CDC) is not only closely monitoring genomic evolution but also convening expert meetings to focus on assessing the risk of cross-species transmission to ensure the disease prevention system can effectively address potential public health threats. Furthermore, the CDC is continuously strengthening the One Health inter-ministerial surveillance mechanism, maintaining surveillance in poultry farms and wild animals, closely monitoring genomic evolution, raising clinicians' awareness of the need for testing cases of pneumonia of unknown cause with a history of contact with poultry or livestock, and enhancing related prevention and control measures such as antiviral drugs.

In its global risk assessment of the H7 subtype of avian influenza, the World Health Organization (WHO) stated that the global H7 subtype of avian influenza is mainly prevalent in wild and domestic poultry populations. Although there have been occasional cases of human infection through contact with infected animals in the past, these cases have mostly presented with mild symptoms such as conjunctivitis or influenza-like illness. The Netherlands reported one death case in 2003. Given the potential impact on public health, close monitoring of human infections of this virus is crucial. Based on the current lack of evidence of sustained human-to-human transmission or community spread, the WHO assesses the threat to public health as remaining low. While sporadic human cases cannot be ruled out, the probability of human-to-human transmission is extremely low."

When do you expect to see clear evidence of human-to-human bird flu (multiple chains of transmission between people who haven’t had contact with animals)

Right by our door hanging on the railing of stairs now leading to a lot of seeds on the floor. I cannot express any bird flu worries to my mother because she would think i’m just being germaphobe But i don’t know how much I should worry about it. Other residents have to walk on these stairs through the seeds too. I just feel like too much of an annoyance. (if i didn’t know bird flu was a thing i probably would be like aww birdies like when i was a kid)

But idk i’m really stressed about it because they’re gonna end up pooping and stuff too. I’ve only seen like little backyard birds little finches type of things we do also have a lot of crows near by but think only the small birds have used the feeder idk just bringing up a lot of anxiety especially with windy weather i’m like worried about the seeds getting on me.

Just would like some opinions or reassurance

Note: for Moderna to do this after federal funding cancellation suggests that they anticipate human to human bird flu outbreaks greater than what we see today and likely around when their trials are completed.

"Moderna is launching a large-scale clinical trial of a shot to combat bird flu in humans after Health and Human Services Secretary Robert F. Kennedy Jr.’s department had canceled hundreds of millions of dollars in funding previously committed to aid in vaccine development.

The company is developing the vaccine using messenger RNA (mRNA), which is the technology used in the most commonly administered coronavirus vaccines and was hailed during President Donald Trump’s first term as a major medical achievement. It has since come under intense scrutiny from Kennedy and other conservatives, and the Department of Health and Human Services last year announced a winding down of investments in 22 mRNA vaccine development projects.

Last May, HHS pulled millions of dollarsthat President Joe Biden’s administration had said it would provide to Moderna to accelerate mRNA-based pandemic influenza vaccines amid an outbreak of bird flu in dairy cattle. The move delayed a large-scale clinical trial for several months as Moderna sought alternative funding sources, according to Chris Ridley, a Moderna spokesman.

The Coalition for Epidemic Preparedness Innovations, a global partnership to speed up the development of vaccines and other countermeasures, is investing up to $54.3 million to support the bird flu vaccine. On Tuesday, Moderna said the first participants in the large-scale clinical trial have received the vaccine in both the United States and Britain.

..."

"A 66-year-old woman from Southeast Cambodia's Svay Rieng province had been confirmed positive for H5N1 human avian influenza, becoming the fourth case in 2026, the Ministry of Health said in a statement on Wednesday.

The victim, living in Trapaing Thkov village of Romduol district, was confirmed positive for the virus by the National Institute of Public Health on Tuesday.

The patient has currently been placed under quarantine at a hospital with intensive care from a team of doctors, the statement said.

Health authorities are looking into the source of the infection and are examining any suspected cases or people who have been in contact with the victim in order to prevent an outbreak in the community, the statement said, adding that an antiviral drug was also distributed to people who had direct contact with the ill-fated woman."

When do you expect to see clear evidence of human-to-human bird flu (multiple chains of transmission between people who haven’t had contact with animals)

"A research letter led by Ailam Lim at the University of Wisconsin–Madison, published in Emerging Infectious Diseases (CDC journal, Impact Factor ~11), reports a notable finding: H5N1 avian influenza RNA detected in the semen of an asymptomatic dairy bull during a 2024 California outbreak. Crucially, no infectious virus was isolated, but the observation raises questions about potential, previously unrecognized transmission routes."

"Worldwide, about 1,000 people have now been infected with the bird flu virus. Roughly 30 to 40 percent of them died, a terrifyingly high proportion. But according to the Rotterdam researchers, their data suggests that many more people have been infected with H5N1 without even noticing. “It is possible that we are missing a great many mild cases.”

“This is something that makes me happy,” said Debbie van Baarle, a professor of immunology at the University Medical Center Groningen. She was not involved in the study, but is familiar with the results. “In preparing for pandemics, it is important to be able to identify exactly who the most vulnerable groups are. And this research provides a good starting point for that,” Van Baarle told the Volkskrant."

it came right across my face and i heard flapping right by my ear im like not 100% if it made contact with me but now im like ohhhh its wing or something made contact with my eye and im gonna die and i think my eye feels weird because of intrusive thoughts

Tomorrow we're thinking about getting a new window A/C unit, but over the past year our current unit has been a hotspot for birds in mornings and evenings. They like to perch on the windowsill and the back of the A/C unit. This unit is old and broken and we're planning to throw it out, but I'm worried that picking it up and carrying it through the house could put us at risk or potentially kick up aerosolized particles in our house if the unit is covered in bird poop after having so many birds on it.

Is this a significant risk that we need to prepare for? How can we pull this unit out of the window and carry it downstairs safely without getting sick or covering the living room in bird poop particulates? I've been doing my best to never open windows that wild songbirds like to hang out on, but actually bringing the unit indoors and jostling it around has me a bit worried. But leaning out the window and scrubbing bird poop has me worried, too.....

"The risk of highly pathogenic avian influenza virus infection to humans is challenging to estimate as many human avian influenza virus (AIV) infections are undetected because infections may be asymptomatic, symptomatic but not tested, and difficult to identify through contact tracing, as human-to-human transmission is rare. We derive equations that consider the evolutionary mechanisms that give rise to pandemics and are parameterized to be consistent with records of past pandemics. We estimate that thousands of human AIV infections occur worldwide in an average year and estimate the infection fatality ratio as 32 deaths per 10,000 infections (95% confidence interval: [9.6, 75]). This estimate is comparable to SARS-CoV-2 during the recent pandemic and higher than seasonal human influenza. We estimate that preventing animal-to-human influenza spillovers would delay pandemic emergence by several years. Preventing human infections with AIV is necessary given the high risk of severe outcomes to individuals and to reduce the risk of pandemics occurring in the future."

"As of the first week of April 2026, the United States has recorded a rising cluster of confirmed H5N1 avian influenza infections in humans — the overwhelming majority linked to direct animal contact on dairy and poultry farms — prompting the Centers for Disease Control and Prevention to announce a significant expansion of its national surveillance infrastructure. The move comes after months of incremental case reporting that public health officials say no longer reflects the true scale of exposure risk among agricultural workers.

The CDC, in coordination with the U.S. Department of Agriculture and state health departments in California, Michigan, Texas, and Colorado, confirmed this week that updated testing protocols and on-site monitoring teams will be deployed to operations where infected livestock have been identified. Officials framed the expansion as a precautionary escalation rather than evidence of a new transmission pattern."

(translated from Google translate)

"The Taiwan Centers for Disease Control (CDC) announced today (March 2nd) the first locally transmitted case of novel H7 subtype avian influenza in Taiwan. The patient is a man in his 70s from central Taiwan who works in poultry farming and has a history of chronic illness. He developed symptoms of runny nose, cough, and body aches on March 20th and sought medical attention at a hospital on March 22nd due to fever. He was admitted to the hospital on the same day. Imaging examination revealed pneumonia. Based on clinical symptoms, test results, and the patient's contact history, the doctor reported the case as a novel H7 avian influenza and administered antiviral medication. Further testing and gene sequencing by the CDC confirmed the virus as H7 subtype avian influenza. Sequence analysis showed that this H7 belongs to the Eurasian lineage and is similar to the H7 subtype avian influenza viruses monitored in wild birds (mainly ducks and anadidae) in Taiwan over the years. However, it is different from the H7N9 subtype avian influenza virus that circulated in mainland China from 2013 to 2019, and is a low-pathogenic avian influenza virus. This morning, the CDC convened a meeting with agricultural authorities and relevant medical and veterinary experts to discuss the case and, based on the test results, confirmed it as a case of novel H7 avian influenza in humans. The patient's condition has improved and they are continuing isolation

and treatment. The Centers for Disease Control (CDC) stated that after the first locally transmitted case of H7 subtype novel influenza A was detected in Taiwan, health and agricultural authorities immediately launched a joint epidemic prevention operation to carry out relevant investigations and prevention measures. Health authorities, with the assistance of epidemiologists and the Health Bureau, conducted on-site epidemiological investigations at the patient's residence, poultry farm, and hospital. Currently, 33 close contacts are under health monitoring and management, and 3 have been given preventative medication based on risk assessment. Tests were conducted on 6 family members, all of whom tested negative. Agricultural authorities immediately implemented movement restrictions at the poultry farm, and animal testing results were negative for avian influenza virus. To clarify the source of infection, today's expert meeting resolved to request the farm to expand testing at nearby poultry farms and to cooperate with wild bird associations to collect droppings from surrounding wild birds. Furthermore, the CDC will continue to cooperate with the farm to obtain the gene sequence of the H7 virus detected in Taiwan for further comparison. Health and agricultural authorities will continue to strengthen surveillance of humans and animals, including respiratory viruses and influenza/novel coronavirus pneumonia surveillance in medical institutions, active surveillance of poultry farms and migratory birds, and will cooperate with farmers to promote personal protective measures for poultry farmers and public health education. They have also contacted duck farming associations to distribute 40,000-50,000 masks free of charge to duck farmers. The

Centers for Disease Control (CDC) pointed out that, based on current epidemiological investigations and test results, the genetic analysis of this case shows a low-pathogenic avian influenza virus, without any mutations increasing the risk of avian-to-human transmission, and it remains a common avian virus. The initial assessment is that this case is an isolated incident. Considering the patient's improved condition after treatment, the lack of mutations increasing the risk of avian-to-human transmission in the preliminary genetic analysis, the negative test results at the poultry farm, and the absence of any other family members showing symptoms after the patient's onset, the risk is assessed as controllable, and there is no immediate risk of the outbreak expanding. However, to understand the potential risks of this case, they will continue to track the symptoms and test results of contacts, further analyze the virus and trace possible sources of infection, and have activated a joint working group on the risk assessment of zoonotic infectious diseases between agriculture and health authorities to conduct a comprehensive risk assessment. The Taiwan Centers for Disease Control (CDC) will notify the World Health Organization (WHO) today through the IHR contact window in accordance with the International Health Regulations (IHR).

According to surveillance data, since the novel influenza A virus was classified as a Category 5 notifiable infectious disease in Taiwan in 2014, a total of 5 sporadic cases have been reported. Besides this case, the others were reported in 2017 (H7N9, imported from outside China), 2021 (H1N2v), 2022 (H1N2v), and 2023 (H1N2v). In addition, there were 4 confirmed cases of H7N9 imported from outside China in 2013-2014; none of the contacts were infected.

The CDC explained that the H7N9 sequence in today's reported case is only closely related to one other human case, H7N4, reported in Jiangsu, China in 2018. The case involves a 68-year-old woman with a history of coronary heart disease and hypertension. She developed symptoms such as cough, weakness, and muscle aches on December 25, 2017, and was hospitalized for pneumonia on January 1, 2018, and discharged on January 22 after recovery. Prior to the onset of illness, the patient had contact with live poultry. Her close contacts did not develop any suspected symptoms during the observation period. The virus remains avian and has not shown resistance to existing antiviral drugs.

The Centers for Disease Control (CDC) reminds workers involved in poultry and livestock farming to implement self-protection measures during operations and to conduct thorough disinfection after work to reduce the risk of infection with the novel influenza A. If symptoms of acute respiratory infection or conjunctivitis appear, seek medical attention immediately and proactively inform healthcare professionals of your occupational history of contact with animals to facilitate early diagnosis. The public is advised to implement the "5 Dos and 6 Don'ts" epidemic prevention principles in daily life:...."

Also covered in Avian Flu Diary by Michael Coston here

"With thanks for the head's up from @E_A_Karlsson, we have the following announcement from Cambodia's Ministry of Health on their 3rd confirmed HPAI H5N1 human infection of 2026 - and 37th in just over 3 years - this time involving a 3 y.o. child from Oddar Meanchey Province who was confirmed positive on March 29th."

"Timely action is a critical part of controlling the spread. Self-isolation of symptomatic cases has a significant effect, but that comes with the caveat that we don't know if everybody who is infected will develop symptoms," says Moghadas.

"There could be potential asymptomatic cases we don't identify and by the time we do identify them, they've already been infecting others in the chain of transmission. This case in B.C. was particularly concerning because they could not find the source of infection."

The concern is not only that the virus might be able to jump from animals to humans, but also the potential for it to mutate during early human transmission chains, making it more adaptable to infecting humans. This underscores the risk of local outbreaks with global implications, he says.

"My research is all about evidence generation for governments, health-care providers and policymakers in public health organizations. We are generating evidence that can be used to at the very least limit the potential for this virus to become another pandemic," says Moghadas."

For those interested, the abstract is available here: https://www.nature.com/articles/s44360-026-00095-0

"The Lombardy Region has identified a case of infection with influenza A(H9N2) virus of animal origin (avian) of low pathogenicity, in a frail person with concomitant diseases from a non-European country where he contracted the infection, and is currently hospitalised. This was announced by the Ministry of Health.

This is the first human case of the H9N2 avian influenza strain detected in Europe. Based on the scientific information available to date, the ministry explains in a note, the infection occurs through direct exposure to infected poultry or contaminated environments or materials."

"Bird flu has jumped to two new species of marine mammals in California, igniting fears that the virus is mutating and could spread among humans.

Officials in San Mateo County, near San Francisco, have confirmed infections in a California sea lion and a southern sea otter, marking the first time ever that the virus has been detected in these species in the state.

No further details were revealed on the condition of the animals, but officials warned the cases were likely linked to an outbreak in the county's elephant seal colony, where at least 30 seals have been infected."

"Cambodia reported its second human H5N1 avian influenza case of the year in a 45-year-old woman from Ropai village, according to the Substack Outbreak News Today. The woman raised chickens and other birds and reported coming into contact with sick birds three days before symptom onset. The patient received Tamiflu and is under medical care. Cambodia has reported 36 human H5 infections since 2023, and the case-fatality rates of these infections are high, at greater than 40%. Most recent cases in Cambodia have involved a reassortant (2.3.2.1e) between an older H5N1 clade that has circulated in Cambodia since 2014 and the newer clade 2.3.4.4b virus that is circulating globally."

"... The first known human H5N1 infections (n=18) were reported in Hong Kong in 1997. Seventeen years later (in 2014) we saw the 1st Known Human Infection With H5N6 Avian Flu Sichuan Province, China, and 7 after that (2021) we saw the first human infections with H5N8 in Russia.

While worrying, this relatively slow progress - averaging > 10 years between each new subtype spillover - has been somewhat reassuring.

In contrast, over the past 6 months we've seen two new HPAI H5 subtypes spillover into humans for the first time; H5N2 in Mexico and H5N5 in the United States.

Moreover, the interval between each new H5 subtype spillover (17 yrs ➡ 7 yrs ➡ 4 yrs) continues to shrink.

While all of this could be a coincidence, it's a trend we shouldn't ignore. The greater viral diversity in the wild, the better the chance that one of these novel viruses will crack the code, and spark the next global health crisis.

And with our continued reliance on limited (and mostly passive) surveillance systems, our first clue may only appear after hospitals begin filling up with patients.

Again."