Preprint: Enhanced Pathogenicity and Contact Transmissibility of Human-origin Avian Influenza H5N1 Clade 2.3.4.4b Genotype B3.13 Compared to D1.1 in Ferrets

 

#19,297

The two main H5N1 genotypes (out of > 100) we are watching in the United States are the B3.13 `Bovine' strain which emerged in Texas Cattle in early 2024, and the D1.1 avian strain that appeared in Canada the following fall and quickly spread through wild birds and poultry across the continent. 

From a distance, it appears that the B3.13 strain produces mainly mild illness in humans (ie. conjunctivitis), while the D1.1 strain has been linked to a number of severe illnesses and several deaths.  

But appearances, particularly when surveillance and testing are limited, can be deceiving. 

• Bovine B3.13 H5N1 infections are probably easier to track because they occur on dairy farms, are more likely to be treated with antivirals, and may be more likely due to `splash' events where infection occurs through the ocular route. 

• While many D1.1 infections occur on poultry farms, it may also be encountered by the general public through contact with wild birds and/or backyard poultry, which makes it more difficult to track. 

Complicating matters, we've seen a number of head-to-head comparison studies (see here, here, and here) that have provided differing assessments of the transmissibility and virulence of these two genotypes. 

In one study using human nasal and airway organoids, D1.1 appeared to be better adapted to human physiology, while in another (see IJID study)  B3.13 caused severe disease, extra-respiratory spread, and lethality in ferrets while D1.1 caused milder disease with no lethality.

To be fair, differences in methods and materials used in these studies can make a huge difference in their outcomes.  

• Some studies have used laboratory-propagated, clinical-origin H5N1 isolates, while others have used full-genome reverse-genetics reconstructions, or engineered PR8 reassortants carrying the relevant H5 and N1 genes from each genotype.

• Some studies used co-housed ferrets, or adjacently-housed ferrets (for airborne transmission), while others used organoids or other in vitro proxies to study replication or receptor binding.

And in all of these studies, researchers have relied on one or two isolates from each genotype, which may ignore a much larger and diverse pool of circulating viruses.  None of which invalidates their findings, but it does make direct comparisons between genotypes more difficult. 

All of which serves as prelude to a new preprint (not yet peer reviewed) which tested transmission and pathogenicity of D1.1 and B3.13 genotypes in co-housed ferrets. 

Using primarily full-genome reverse-genetics viruses, these researchers found that - out of the box - the B3.13 genotype appeared to be better adapted to mammalian hosts than D1.1.

They cite:

HPhTX B3.13 infection resulted in more severe clinical disease and enhanced viral shedding, with evidence of increased transmission relative to HPhLA D1.1. 

But 

. . . HPhLA D1.1 showed rapid acquisition of the mammalian-adaptive mutation E627K in infected ferrets and both E627K and Q194K in the only fatal contact animal. 

The B3.13 used in this experiment was better adapted, but more stable. D1.1 appears to be more of a wildcard.  While neither have acquired the ability to spread efficiently among humans, both require continued monitoring for further changes.  

This is a lengthy (66 pages) and at times technical paper, so I've only posted the abstract and some excerpts from the conclusion.  Those desiring a deeper dive will want to follow the link to read it in its entirety.  

I'll have a bit more after the break.

Enhanced Pathogenicity and Contact Transmissibility of Human-origin Avian Influenza H5N1 Clade 2.3.4.4b Genotype B3.13 Compared to D1.1 in Ferrets
 Ahmed M. Elsayed, Ramya S. Barre, Mahmoud Bayoumi, Alvaro Padron, Hossein Batebi, Vinay Shivanna, Roy N. Platt, Fiona Burmeister, Joshua Castro, Arash Rahmani,  Juliane Lang,  Chengjin Ye,  Timothy J.C. Anderson, Roland Netz, Aitor Nogales,  Robert P. de Vries, Geert-Jan Boons, Adolfo Garcia-Sastre,  Elsayed M. Abdelwhab,  Gregory C Ippolito, Luis Martinez-Sobrido
doi: https://doi.org/10.64898/2026.08.10.744032
This article is a preprint and has not been certified by peer review 
 
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Abstract

Since its emergence in 2020, multiple genotypes of the H5N1 clade 2.3.4.4b have been identified, with B3.13 and D1.1 emerging in the USA as two major and concerning genotypes. However, their relative pathogenicity and transmissibility in mammals have not been fully elucidated. 

We compared the pathogenicity and transmissibility of the first two human H5N1 clade 2.3.4.4b cases caused by B3.13 in Texas (A/Texas/37/2024; HPhTX B3.13) and D1.1 in Louisiana (A/Louisiana/12/2024; HPhLA D1.1) in a ferret model of infection and transmission. 

HPhTX B3.13 infection resulted in more severe clinical disease and enhanced viral shedding, with evidence of increased transmission relative to HPhLA D1.1. 

Histopathological analysis revealed more extensive lung pathology in animals infected with HPhTX B3.13, consistent with increased viral loads and inflammatory responses. Importantly, both genotypes showed no significant differences in reactivity to ferret sera raised against candidate vaccine virus (CVV) strains, receptor binding properties, or neuraminidase (NA) activity and thermostability. 

Whole-genome sequencing revealed no adaptive mutations in HPhTX B3.13 following infection or transmission. In contrast, HPhLA D1.1 showed rapid acquisition of the mammalian-adaptive mutation E627K in infected ferrets and both E627K and Q194K in the only fatal contact animal. 

Both mutations were associated with enhanced polymerase activity and computational analyses suggested that they enhance interactions with the mammalian host factors ANP32A and B. 

Our findings indicate that B3.13 is already well adapted for mammalian infection and transmission whereas D1.1 retains evolutionary potential through the rapid acquisition of adaptive mutations, highlighting important genotype-specific differences relevant to zoonotic risk assessment and pandemic preparedness.

(SNIP)

 Overall, our study supports a model in which mammalian adaptation of contemporary HPAIV H5N1 is driven predominantly by optimization of viral polymerase function rather  than by changes in receptor specificity. The genetic stability of HPhTX B3.13, together with its high polymerase activity, efficient transmission, and increased pathogenicity, suggest that this genotype is already well adapted for mammalian replication.

In contrast,  HPhLA D1.1 remains incompletely adapted but rapidly acquires mammalian-adaptive PB2 mutations during replication in ferrets. The identification of PB2 Q194K as a cooperative mutation that enhances the activity of PB2 E627K expands our understanding of influenza polymerase adaptation and identifies a potential molecular marker for the surveillance of emerging H5N1 viruses with increased zoonotic potential.

Finally, this study has some limitations. 

First, transmission was assessed in a single  mammalian model with a relatively small sample size under controlled laboratory conditions, which may not fully recapitulate natural exposure settings or host diversity. 

Second, only one isolate per genotype was evaluated. Third, the potential contribution of sex to pathogenicity or transmission was not assessed since only female ferrets were used in this study and because some previous studies used male ferrets 17,72 . 

Finally, our in silico computational analysis suggested that the PB2 mutations 194K and 627K affect  PB2-ANP32 binding in a host-dependent manner, with APN32A maintaining a more stable association than ANP32B and showing reduced binding stability. However, future studies are needed to confirm this hypothesis. 

       (Continue . . . )

The caveat to all of this is that while neither genotype appears ready for prime time - both were collected back in 2024 - and evolution never stops. Existing genotypes evolve slowly through antigenic drift or adaptation, while new genotypes can emerge via reassortment (antigenic shift). 

We've even seen new subtypes emerge (see J. Virology: Risk assessment of avian influenza A(H5N5) virus from the first human case using the ferret model) during this epizootic. 

There are no guarantees how long B3.13 - or D1.1 - will remain the primary HPAI threats going forward.  

Right now, as the days grow shorter in the Northern Hemisphere, migratory birds that spent their summer in their high latitude roosting spots are starting to move south (see Sci Repts.: Southward Autumn Migration Of Waterfowl Facilitates Transmission Of HPAI H5N1).

As we discussed a year ago, in H5Nx: Reassort & Repeat, the fall can often bring abrupt changes.  

While it is always possible the next wave will be less virulent, last year South Korea's MAFRA reported 3 different subtypes of HPAI (H5N1, H5N6, H5N9) in wild birds, and significantly increased infectivity. 

Which makes now a good time for poultry producers - from commercial operations to back-yard hobby farms - to review their biosecurity procedures, and to make necessary adjustments before the fall wave arrives. 

Preprint: Clinical outcomes of early aspirin versus non-aspirin NSAID use in adults hospitalized with influenza: A retrospective study

Photo Credit –CDC PHIL

Note: Nothing in this blog post should be construed as specific medical advice - as individual needs may vary - and everyone should consult their own doctor. The following is presented for educational uses only.

 

#19,296

Sixteen years ago, in A Hot Topic For Further Research, we saw a retrospective analysis in the Journal of the Royal Society of Medicine showing the risk of mortality increased by roughly 33% when antipyretics (aspirin, paracetamol, and diclofenac) were used in influenza-infected (non-human) animals.

While the mechanism behind this reported increased mortality wasn't established, it was suggested that the reduction of the natural host response to infection - fever - may have been a contributing factor.

There were a lot of limitations to that study, not the least of which is that research on mice, chickens, and even ferrets isn’t always applicable to humans. Over the next few years, we saw several other studies emerge, including:

• In 2011, in A Feverish Debate, the well respected Wellington based Medical Research Institute of New Zealand, published a paper (Antipyretic therapy for influenza infection—benefit or harm?) in the New Zealand Medical Journal that questioned the conventional wisdom of using these antipyretic drugs with influenza.

• Also from 2011 - the American Academy of Pediatrics (AAP) released a report on the use of antipyretics in children, suggesting that we ought not over-treat fevers (Clinical Report—Fever and Antipyretic Use in Children)

• And in 2013, in Adding To A Feverish Debate, we looked at a study in the Journal of Pediatrics on another possible (albeit, rare) adverse effect seen in a small number of young children with fever and dehydration at a hospital in Indiana who received treatment with NSAIDs - AKI or Acute Kidney Injury.

Somewhat related to all of this have been studies suggesting that the concurrent use of antipyretics may inhibit the immune response when receiving vaccines (see Anti-Inflammatory Meds And Vaccines and Common Pain Relievers May Dampen Vaccination Benefits).

While none of these studies provided definitive proof of harm, they (and others) have raised some interesting questions.

We revisited the topic in 2015's JJID: Evaluating The Mortality Risks Of Taking NSAIDs & ASA With Influenza, which - while subject to a number of limitations - provided some reassurance on the use of antipyretic drugs with influenza, finding that:

We found no compelling evidence that NSAID or ASA use influenced mortality in severe pH1N1.

A 2020 Danish study, published in JAMA (Association of Nonsteroidal Anti-inflammatory Drug Use and Adverse Outcomes Among Patients Hospitalized With Influenza) was similarly unable to find a link between NSAID use and increased mortality with influenza.

In this study, NSAID use was not associated with a clinically significant increased risk of ICU admission or death in patients hospitalized with influenza. While studies on the association of NSAIDs with the disease course of COVID-19 are clearly needed, the currently available data, including the present study, do not seem to support strong recommendations against using NSAIDs in patients with viral pneumonia. 

That said, this study did not establish that NSAIDs are harmless in every patient or scenario, as long-term use of NSAIDs was associated with ICU admission.

While the data has been mixed, there has also been little evidence to suggest taking NSAIDs following vaccination blunts the immune response (see  No Evidence That Analgesic Use after COVID-19 Vaccination Negatively Impacts Antibody Responses), although prophylactic use remains a concern. 

All of which brings us to a new preprint (not yet peer reviewed) by researchers at the University of Minnesota, which goes as far as to suggest possible benefits from NSAIDs in treating influenza -  although their study was small, single-center, and nonrandomized - making their findings preliminary at best. 

I've reproduced the abstract and a brief excerpt below. Follow the link to read the full report.  I'll have a postscript after the break.

Clinical outcomes of early aspirin versus non-aspirin NSAID use in adults hospitalized with influenza: A retrospective study
Suk Yin Chan-Colenbrander, Qi Wang
doi: https://doi.org/10.64898/2026.08.05.26359840
This article is a preprint and has not been peer-reviewed [what does this mean?].

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Abstract

Seasonal influenza remains a major cause of morbidity and mortality worldwide. Although neuraminidase inhibitors improve clinical outcomes, influenza-related deaths persist. We evaluated the associations of early aspirin and non-aspirin nonsteroidal anti-inflammatory drug (NSAID) use with clinical outcomes in adults hospitalized with influenza. This retrospective study included adults admitted to the University of Minnesota Medical Center from 2016 to 2018.

Multivariable logistic and Cox regression models adjusted for age, sex, race, smoking status, influenza vaccination status, and cardiovascular burden were used to evaluate the associations of early aspirin and NSAID use with clinical outcomes. Among 2,816 patients screened, 320 had laboratory-confirmed influenza.

Compared with unvaccinated patients, vaccinated patients had lower rates of ICU admission (11% vs. 24%; P = 0.003) and ventilatory support (6% vs. 15%; P = 0.009).

In unadjusted analyses, aspirin users had higher rates of cardiovascular complications (27% vs. 16%; P = 0.028) and lower 3-year survival (57% vs. 72%; P = 0.008).

In contrast, NSAID users had lower rates of ICU admission (7% vs. 18%; P = 0.042), cardiovascular complications (4% vs. 23%; P = 0.001), and renal complications (9% vs. 25%; P = 0.010), and higher 1-year (98% vs. 78%; P = 0.0004) and 3-year survival (89% vs. 63%; P = 0.0001).

After adjustment, aspirin use was not independently associated with any study outcome.

Early NSAID use was independently associated with lower odds of renal complications (aOR, 0.35; 95% CI, 0.13–0.97; P = 0.044) and lower hazards of 1-year (aHR, 0.11; 95% CI, 0.01–0.81; P = 0.030) and 3-year mortality (aHR, 0.33; 95% CI, 0.14–0.77; P = 0.011).

Sensitivity analyses using the Charlson Comorbidity Index yielded similar findings. Prospective studies are needed to determine whether early non-aspirin NSAID use improves clinical outcomes in adults hospitalized with influenza.

       (SNIP)

In this study, early non-aspirin NSAID use was independently associated with lower risks of renal complications and reduced 1- and 3-year mortality, whereas early aspirin use was not independently associated with clinical outcomes after multivariable adjustment. These findings emphasize the importance of distinguishing aspirin from non-aspirin NSAIDs in influenza research and raise the possibility that  earlier initiation of non-aspirin NSAIDs during influenza infection may be associated with improved clinical outcomes.

Prospective studies are warranted to determine whether these observed associations are causal and to define the optimal timing, dosage and role of non-aspirin NSAIDs as adjunctive therapy in adults hospitalized with influenza. 

        (Continue . . . ) 

While claims of potential benefits from non-aspirin NSAIDs in treating adult influenza patients may be premature, the pendulum (for now) appears to have swung away from concerns that it may be causing increased mortality.

Further research is needed, of course.

But this tortured route is a reminder why we don't cherry pick one scientific paper, and stubbornly cite it year after year. Science evolves, and our understanding of the world around us inevitably changes over time. 

FAO: Expect The Unexpected - Guidelines on Emergency Response Preparedness in Agriculture in Europe and Central Asia

 

#19,295

Even in years when we aren't facing a looming, and likely record-setting, El Nino - which may bring unexpected droughts and floods, or searing heat, to different parts of the world - the agricultural sector regularly faces numerous threats, including emerging and reemerging disease threats (avian flu, African Swine Fever, and New World Screwworm, etc.)

Add in rising diesel fuel costs, fertilizer shortages, falling water tables, wildfires, hail, soil erosion, and a host of other threats, and it is no wonder that so many farmers (and consumers) are under increasing economic pressure. 

While most of these threats are beyond our control, we can prepare for them; which is the overriding message of an 84-page FAO guidance document released this past week for agricultural interests in Europe and Asia, but which most is applicable worldwide. 

First, some excerpts from an FAO news release, followed by a link and a brief summary for the the document.  

Expect the unexpected – FAO guidance on emergency response preparedness

© FAO/Igor Salinger

13/08/2026

Natural hazards are unavoidable. The way we mitigate and manage them is within our control – and preparedness is the first line of defence.

The Europe and Central Asia region is vulnerable to several types of natural hazards, including floods, storms, droughts, wildfires and landslides. Due to the effects of climate change, climate-related hazards in particular have increased in frequency and intensity over the past few decades.

The agriculture sector and food security are heavily impacted by these phenomena. FAO estimates that the agriculture sector absorbs more than 26 percent of total economic costs from climate-related disasters.

National governments have a responsibility to act when – and before – disasters occur. The Food and Agriculture Organization of the United Nations (FAO) released the publication Guidelines on emergency response preparedness in agriculture in Europe and Central Asia, providing a comprehensive and practical framework to support governments and partners in strengthening disaster preparedness for effective emergency response in the agriculture sector.

Why is preparedness non-negotiable?

Preparedness measures not only lessen the time and money spent on disaster response, but also reduce agricultural damage and loss. According to the United Nations Office for Disaster Risk Reduction (UNDRR), every USD 1 invested in disaster risk reduction can save up to USD 15 in post-disaster recovery – investing in preparedness, therefore, literally pays off.

“Consisting of two parts, the guidelines cover measures related to each agricultural subsector regarding the impacts of various hazards, such as droughts, heatwaves, hurricanes, floods, forest fires, plant and animal pests and diseases, and include specific case studies that focus on the Europe and Central Asia region,” explains Daniela Mangione, FAO Field Programme Officer and Resilience Focal Point at the FAO Regional Office for Europe and Central Asia, who provided technical guidance for the publication. “Smallholder farmers are especially susceptible to the adverse effects of disasters and hazards, as their lives and livelihoods are largely dependent on the agricultural sector. By investing in risk reduction, which includes increasing preparedness for response, countries contribute to building more sustainable and resilient agriculture and food systems, better equipped to handle future shocks and stresses.”

       (Continue . . . )
 

Guidelines on emergency response preparedness in agriculture in Europe and Central Asia

Year of publication 2026
ISBN 978-92-5-140771-4
Permanent link
https://openknowledge.fao.org/handle/20.500.14283/ce0228en
To cite or share
https://doi.org/10.4060/ce0228en

Synopsis (short abstract)

Across the Europe and Central Asia region, the increasing frequency and severity of various types of hazards – from droughts and floods to animal and plant pests, diseases, and wildfires - are adversely impacting agrifood systems and food security. In this context, preparedness is no longer optional; it is a strategic cost-effective strategy to help countries protect livelihoods, especially of smallholder farmers who are at risk and vulnerable to the adverse impacts of these hazards.

Reducing disaster risks and impacts, through enhancing preparedness for response is crucial to build agrifood systems that are more sustainable and resilient to future shocks and stresses. These guidelines provide a comprehensive and practice framework to support governments and partners in enhancing preparedness for effective response in the agriculture sector - in particular for the crops, livestock, forestry, fisheries and aquaculture subsectors. It includes specific case studies that focus on the Europe and Central Asia region as well as provides an extensive list of resources, tools and weblinks that will support governments, policymakers, researchers and development practitioners in designing, planning, implementing and monitoring preparedness interventions. 

These guidelines are divided into two parts. The first part outlines the different disaster risk reduction components on which it is based and closely linked to, including disaster risk assessment, early-warning systems, anticipatory action, contingency planning, and institutional capacity development. The second part provides technical guidance and implementation checklists for enhanced preparedness across ten thematic areas and agricultural subsectors, such as animal health, plant pests, forest, livestock, food safety, One Health, among others.

While most of my readers aren't farmers, and won't feel the need to read the report in full, its takeaway message still applies to everyone on this planet.  There are no guarantees that tomorrow will be like yesterday, and we ignore the threats around us at our own peril. 

Next month is National Preparedness Month, and - as we've done every year for nearly 2 decades - we'll focus on individual, community, and national preparedness. 

For those who'd like a headstart, a sampling of preparedness essays from last year: 

Denk Vooruit: The Netherlands National Citizen Preparedness Drive

#NPM: DOE Resource Adequacy Report & Prepping For Power Outages

Frontiers: HPAI: Pandemic Preparedness for a Scenario of High Lethality with No Vaccines

Australia H5N1 Update: 1st Detection in A Penguin (Victoria) - Penguin Vaccination Campaign Begins Monday

 

#19,294

In the 24 hours between Thursday's update and the latest (Friday's) above, more than 1,800 new hotline reports were received from the public, while the number of confirmed H5N1 `events' rose from 186 to 219. 

The states of South Australia and Victoria continue as the nation's hotspots, with Victoria overnight reporting the first confirmed local penguin infected with the virus.

This little penguin was found on Phillip Island, home to one of the largest colonies (est. 40,000) of little penguins in the world.  First today's announcement, followed by details on the state's plan to vaccinate a large number of endangered penguins. 

H5 bird flu update: new detections in wild birds

15 August 2026

H5 bird flu vaccinations of Phillip Island’s little penguins will begin on Monday evening following Victoria’s first detection of the disease in a penguin.

Three new positive detections of H5 bird flu have been confirmed in wild birds in Victoria, showing spread to East Gippsland. No detections have been found in poultry or other animals.

The latest positive detections are:

• One little penguin from Phillip Island
• One crested tern from Lakes Entrance
• One crested tern from Dromana on the Mornington Peninsula.

Chief Biodiversity Officer James Todd said the detection at Lakes Entrance is significant because it confirms H5 bird flu in East Gippsland and shows the virus is continuing to move through wild bird populations across Victoria.

‘The Gippsland Lakes are also habitat for large numbers of seabirds, shorebirds and waterbirds at higher risk from H5 bird flu, so spread of the virus through this area is likely to have significant impacts on wildlife,’ Mr Todd said.

Chief Veterinary Officer Dr Graeme Cooke said Agriculture Victoria and Phillip Island Nature Parks activated plans to vaccinate more than 5,000 little penguins at Phillip Island and St Kilda as soon as the Federal Government authorised the use of H5N1 vaccines for priority native bird species.

‘Agriculture Victoria is working closely with Phillip Island Nature Parks to support vaccination of little penguins from Monday.

‘While the first detection in a little penguin is a concern, vaccination of little penguins on Phillip Island remains a meaningful way to help protect this important colony.

‘Vaccination is not a guarantee against infection but remains an important tool that may help reduce the impact of H5 bird flu in this population.

‘We will continue to monitor the colony closely and adapt our approach as new information becomes available,’ he said.

Community members should avoid touching sick or dead wildlife wherever possible and keep pets away from animals and carcasses. If disposal is required in an affected area, follow the advice provided and take appropriate precautions.

If you see sick or dead birds or wildlife, report it via the Agriculture Victoria website or call the Emergency Animal Disease Hotline on 1800 675 888.

To keep up to date with Victoria's response to H5 bird flu, visit birdflu.

Media contact: sboc.media@agriculture.vic.gov.au

At the time of the following release, no confirmed infections of H5N1 had been reported in penguins, although given H5's history, it was all but inevitable. While only on fraction of the island's birds can be vaccinated, it will hopefully reduce the virus's impact on the colony. 

Protecting Victoria's Penguins From Bird Flu

Published:Wednesday 12 August 2026

The Carroll Labor Government is moving quickly to protect Victoria’s little penguins from H5 bird flu.

Following the Commonwealth’s vaccine announcement yesterday, doses have arrived at Phillip Island and are ready to be administered early next week, pending final regulatory approvals.

More than 5,000 little penguins at Phillip Island and St Kilda are expected to be vaccinated as part of the program.

Vaccinating wild birds is challenging because each bird needs to be caught twice to receive two doses.

Little penguins usually return to the same colonies and burrows, providing a rare opportunity to vaccinate a wild population and monitor their response over time.

Vaccination won’t stop H5 bird flu from circulating, but it can help reduce its impact alongside existing biosecurity, surveillance and wildlife response measures.

The broader vaccine rollout will also prioritise vulnerable species held in captivity, including animals in zoos and other managed populations across Victoria.

The rollout comes as H5 bird flu continues to be detected in wild birds, predominantly greater crested terns, with new cases at Phillip Island, Mildura, Warrnambool, Hamilton, St Andrews Beach and Hawkesdale.

There have been no detections of H5 bird flu in little penguins in Victoria or Australia to date.

Over the past three years, Phillip Island Nature Parks has invested significantly in protecting little penguin habitat.

Victoria has invested more than $130 million in biosecurity and continues to strengthen surveillance and respond as the situation evolves. 

Michigan DOH Confirms H1N2v (swine flu) in Fair Exhibitor

Credit Wikipedia


#19,293

Three days ago, in Kent County MI Health Department Bulletin on Swine Flu (in pigs) at Local Fair, we saw a local health department advisory on a pig death at the Kent County, MI county fair, and reports of `influenza-like' illness among individuals who had contact those pigs.

Late yesterday the Michigan Dept of Health and Human Services (MDHHS) confirmed at least on case of human H1N2v infection in a pig exhibitor.   

While details on the infected individual are scant (no age, condition, treatment, etc. provided) - and there is no word on any additional suspected cases - local and state public health authorities are urging anyone who attended the Kent County fair to be alert to to be alert to symptoms and take appropriate precautions.

The CDC's Assessment of the Risk from these viruses reads:

 

Sporadic infections and even localized outbreaks among people with variant influenza viruses may occur. All influenza viruses have the capacity to change and it’s possible that variant viruses may change such that they infect people easily and spread easily from person-to-person. The Centers for Disease Control and Prevention (CDC) continues to monitor closely for variant influenza virus infections and will report cases of H3N2v and other variant influenza viruses weekly in FluView and on the case count tables on this website.

The CDC's IRAT (Influenza Risk Assessment Tool) currently lists 3 North American swine viruses as having at least some pandemic potential (2 added in 2019).

H1N2 variant [A/California/62/2018]  Jul   2019   5.8  5.7 Moderate

H3N2 variant [A/Ohio/13/2017]          Jul   2019   6.6  5.8 Moderate

H3N2 variant [A/Indiana/08/2011]      Dec 2012   6.0  4.5 Moderate

 First the MDHHS statement, after which I'll have a bit more. 

MDHHS confirms detection of influenza A H1N2 variant (swine flu) in Michigan resident

August 14, 2026

LANSING, Mich. – The Michigan Department of Health and Human Services (MDHHS), Kent County Health Department (KCHD) and Ionia County Health Department have identified a human case of influenza A H1N2 variant (swine flu) in an Ionia County resident who was a swine exhibitor at the Kent County Youth Fair. The fair took place Aug. 3-8 at the Grand Agricultural Center of West Michigan in Lowell.

The individual tested presumptive positive at the MDHHS Bureau of Laboratories for swine flu and was confirmed by the Centers for Disease Control and Prevention (CDC) on Friday.

MDHHS and KCHD have been reaching out to swine exhibitors and their families who visited the swine barns at the Kent County Youth Fair to identify any additional illnesses in those who may have been exposed to influenza from infected pigs. KCHD has alerted providers in the area to watch for patients presenting with respiratory symptoms who report exposure to swine or visited the fair.

“While the risk to the general public remains low, we want visitors who attended the Kent County Youth Fair to be alert to symptoms and take appropriate precautions,” said Dr. Natasha Bagdasarian, chief medical executive. “Anyone who develops flu‑like symptoms after possible exposure should contact their health care provider and let them know about their recent contact with pigs at the fair. Individuals who are sick should stay home until they have fully recovered.”

“It’s not unusual for flu viruses to occur in pigs, and while rare, those flu viruses can be transmitted to people by sick pigs,” said Dr. Nora Wineland, State Veterinarian, Michigan Department of Agriculture and Rural Development (MDARD). “MDARD encourages exhibitors to follow disease prevention practices and work with their veterinarian if they suspect illness in an animal. It is still safe to enjoy your local fair, and visitors are encouraged to follow simple hygiene practices to help keep both people and animals healthy.”

Pigs may be infected with swine influenza viruses that are different from human flu viruses. Swine flu viruses spread among pigs and – while rare – they can spread from pigs to people too. Spread of swine flu viruses from a pig to a person is thought to happen in the same way that human flu viruses spread; mainly through droplets when infected pigs cough and sneeze.

MDHHS reiterates precautions the public can take to avoid potential exposure at farms, fairs and exhibits:

• Do not eat or drink in livestock barns or show rings.
• Do not take toys, pacifiers, cups, baby bottles, strollers or similar items into pig areas.
• Anyone who is at high risk of serious flu complications should avoid contact with pigs and swine barns when attending a fair.
• Get an annual influenza vaccination.

Below are some steps you can take to protect yourself and prevent the spread of any illness:

• Wash hands often with soap and water. If soap and water are not available, use an alcohol-based hand rub.
• Avoid touching your eyes, nose and mouth. Germs spread this way.
• Cover your nose and mouth with a tissue when you cough or sneeze. Throw the tissue in the trash after you use it.
• Avoid close contact with sick people. If you are sick, stay home from work or school until your illness is over.
• Avoid contact with pigs if you have flu-like symptoms. Wait seven days after your illness started or until you have been without fever for 24 hours without the use of fever-reducing medications, whichever is longer.

Symptoms of variant influenza infection in people are similar to those of seasonal flu viruses and may include:

• Fever.
• Cough.
• Runny nose.
• Body aches.
• Nausea.
• Vomiting.
• Diarrhea.

Variant influenza infections, including influenza A H1N2 can sometimes cause severe disease, even in healthy people.

Severe illness can include complications, such as pneumonia, which may require hospitalization, and in some cases can result in death.

People who are at high risk of developing complications if they get variant influenza infection include:

• Children younger than five years of age.
• People 65 years of age and older.
• Pregnant people.
• People with certain long-term health conditions, such as asthma, diabetes, heart disease, weakened immune systems and neurological or neurodevelopmental conditions.

The time period it takes from exposure to illness for variant influenza is similar to that of seasonal influenza, which can be up to 10 days, but is most commonly three days. Currently, there is no human vaccine for swine flu and the seasonal flu vaccine will not protect against swine flu; however, prescription antiviral drugs, such as oseltamivir and zanamivir, are effective in treating swine flu in humans. Early treatment works best and may be especially important for people with a high-risk condition.

For more information, visit CDC.gov/Swine-Flu.

Most (but not all) swine variant infections are mild or moderate, self-limiting, and are clinically indistinguishable from regular seasonal influenza.

Since most people never see a doctor or get tested for uncomplicated `flu-like symptoms' (see pyramid graphic above), it is assumed that many swine variant infections go unreported.

During a small outbreak of H3N2v (n=13) 15 years ago, researchers estimated that fewer than 1 in every 200 cases was identified (see CID Journal: Estimates Of Human Infection From H3N2v (Jul 2011-Apr 2012).

Results. We estimate that the median multiplier for children was 200 (90% range, 115–369) and for adults was 255 (90% range, 152–479) and that 2055 (90% range, 1187–3800) illnesses from H3N2v virus infections may have occurred from August 2011 to April 2012, suggesting that the new virus was more widespread than previously

 

While the pandemic risk from swine variant viruses is currently thought to be low, these viruses continue to reinvent themselves as they circulate in pigs, and so we pay very close attention whenever they jump species to humans.

(Referral) OFFLU Statement: Incursion of HPAI H5 Into Australia and New Zealand . . . .

 

#19,292

This week OFFLU - the WOAH/FAO joint network of expertise on avian influenza - published a 33-page statement which serves as both a detailed account on the opening 6 weeks of the first incursion of HPAI into Australia/New Zealand, and a One-Health technical briefing on the likely implications of H5 HPAI for the region.

This statement has an excellent pedigree, and many of the authors will be familiar names to regular readers of this blog. 

Due to its length, rather than try to summarize it, I've posted the Executive summary and and a brief excerpt, and would urge my readers to follow the link to read it in its entirety.  

I'll have a brief postscript after the break.  

10 August 2026

OFFLU WILDLIFE STATEMENT IV:

INCURSION OF HIGH PATHOGENICITY AVIAN INFLUENZA H5 INTO AUSTRALIA AND NEW ZEALAND, WITH POTENTIAL TO IMPACT WILDLIFE POPULATIONS AND TO SPREAD FURTHER IN OCEANIA

Thijs Kuiken — co-chair, OFFLU Wildlife Technical Activity, Lineke Begeman — lead, OFFLU Wildlife Technical Activity, Andrew Breed — co-chair, OFFLU Wildlife Technical Activity, Ruth Cromie, Jolene Giacinti, Manabu Onuma, Laura Roberts, Yoshi Sakoda, David Stallknecht, Marcela M. Uhart — chair, OFFLU Steering Committee, Jonas Waldenström, Michelle Wille 

Executive summary

What was long expected, has now come to pass: high pathogenicity avian influenza H5 (HPAI H5) has been detected for the first time in wild birds in Australia in June 2026 and in New Zealand in July 2026.

HPAI H5 has a high burden of disease for poultry and wildlife, as well as a zoonotic risk for humans. Since the emergence of HPAI H5 (specifically, the A/Goose/Guangdong/1/1996 lineage)in Asia in 1996, it has been detected in ever more continental regions. It spread from Europe to North America in 2021, to South America in 2022, and to the Antarctic region (Antarctica and sub- Antarctic islands) in 2023. Since its incursion in the Antarctic region, it spread nearly 6,500 km eastwards in two years, from South Georgia in the South Atlantic Ocean in October 2023 to Heard Island in the southern Indian Ocean in October 2025.

It is likely that HPAI H5 was carried from the Antarctic region to Australia and New Zealand by migratory seabirds. Between 14 June and 31 July 2026, HPAI H5 was detected in 1 Brown Skua (Stercorarius antarcticus) and 17 giant petrels (Macronectes sp.) on the coast of Australia, and 1 Brown Skua on the coast of New Zealand. These species breed in spring in the Antarctic region, where they are known to have been infected by HPAI H5. In the non-breeding period, these species may disperse widely, including northwards to waters off the coasts of Australia and New Zealand. Preliminary phylogenetic analysis shows that the HPAI H5 virus detections in wild birds in Australia are closely related to viruses from Heard Island in the Antarctic region.

HPAI H5 has subsequently spilled over from these seabirds to resident bird species in Australia and New Zealand. In Australia, HPAI H5 has been detected in 34 Greater Crested Terns (Thalasseus bergii) as of 31 July 2026. The Greater Crested Tern is a largely resident species in Australia and occurs widely along the coast and offshore islands, a habitat shared with many other seabird species. In New Zealand, HPAI H5 has been detected in one Swamp Harrier (Circus approximans) as of 31 July 2026. The Swamp Harrier is a resident species in New Zealand. In winter it feeds largely on carrion, which is a likely source of infection in avian scavengers.

Based on the sequence of events in other continents, HPAI H5 is likely to spread among wild birds and mammals in Australia and New Zealand. The main wildlife groups at risk are seabirds (e.g. gannets, terns and albatrosses), other waterbirds (e.g. ducks, swans and grebes), pinnipeds (e.g. seals and sea lions), and predatory and scavenging birds and mammals (e.g. raptors, corvids, Dingoes (Canis familiaris dingo) and quolls). From Australia and New Zealand, HPAI H5 may spread to other parts of Oceania (Melanesia, Micronesia, Polynesia), most likely via medium- or long-distance movements of wild birds.

The potential conservation impact from HPAI-H5-associated wildlife morbidity and mortality in Oceania is enormous. Oceania contains many geographically restricted and threatened wildlife populations. For susceptible species, particularly colony-nesting seabirds and pinnipeds, additional mortality associated with HPAI H5 could compound existing pressures on populations.

Although it is not possible to stop the geographical spread of HPAI H5, there are response options to reduce its spread and impact on wildlife, as well as the risk of such HPAI panzootics occurring in the future. Short-term response options include expanding and improving avian influenza surveillance in wildlife, coordination of surveillance across Oceania, removal of infected wildlife carcasses, management of human activities in regions with affected wildlife, vaccination of threatened wildlife species, and avoidance of activities that harm or disturb wildlife and theirhabitats. In case of HPAI H5 spillover to poultry (which has so far not been reported in Australia or New Zealand), short-term response options include rapidly controlling outbreaks and limiting concurrent infections in poultry populations, thereby reducing opportunities for continued viral evolution and recurrent spillback into local wildlife. Medium- and long-term response options include long-term monitoring of impacted wildlife populations, increasing resilience of susceptible wildlife populations (including by actively reducing other threats and promoting actions to enable recovery of populations) and reducing the risk of HPAI emergence and spillover from poultry in the future.

Post scriptum (10 August 2026): Following the drafting of this statement, further cases of HPAI H5 have been detected in wild birds in Australia. These include: a mass mortality event in Greater Crested Terns in South Australia involving over 80 sick or dead individuals. Several detections have been made in Silver Gulls (Chroicocephalus novaehollandiae), a widespread resident species in Australia and New Zealand that occurs both on the coast and inland, including wetland habitats and urban environments. A single detection has been made in an Australian Magpie (Gymnorhina tibicen), a widespread resident species in Australia, member of the Artamidae family and is omnivorous. As of 10 August 2026, there have been 231 confirmed detections of H5 HPAI in wild birds in Australia (10 in Western Australia, 163 in South Australia, 53 in Victoria, 4 in New South Wales and 1 in Queensland), while there the number of confirmed detections in New Zealand has remained at two.

        (SNIP)

The potential conservation impact on the wildlife of Oceania is enormous. According to the IUCN Red Data List, a disproportionately large number of mammalian and avian species in Oceania face high extinction risks. In part this is due to island biogeography, and threats such as invasive species and climate change. The IUCN Red Data List shows 248 avian species in Oceania at the top three levels of extinction risk: 48 Critically Endangered, 67 Endangered and 133 Vulnerable (Appendix 1). Of these species, 90 occur in Australia, 83 in New Zealand and 150 in the rest of Oceania. Similarly, 158 mammalian species are listed at the top three extinction risk levels: 28 Critically Endangered, 58 Endangered and 72 Vulnerable (Appendix 2). Of these species, 76 occur in Australia, 14 in New Zealand and 90 in the rest of Oceania. These appendices are not intended to imply that all listed species are equally susceptible to HPAI H5 virus infection or mortality. Rather, they identify species for which additional mortality could have important conservation consequences and provide a starting point for prioritizing species for further HPAI risk assessment.  

        (Continue . . . )

The history of HPAI's global expansion suggests that as it conquers new territories, it encounters new host species and previously unseen LPAI viruses, which can promote both adaptation and reassortment. 

In the first three years after H5N1's arrival in North America more than 100 new genotypes were identified - and while most were no improvement on its ancestors - at least three new reassortants of note emerged: 

• B3.13 aka the `bovine' strain affecting dairy cattle in at least 19 states and infecting dozens of humans
• D1.1   a wild bird/poultry strain which has spilled over into > a dozen people in Washington State and a teenager in British Columbia
• D1.2  a wild bird/poultry strain which recently detected in poultry and 2 pigs in Oregon

We've also seen new subtypes emerge, including H5N2, H5N5, H5N6, and H5N9.  

As any kid with an erector set can tell you (yes, I'm showing my age. Feel free to substitute Lego (tm)), the larger and more varied supply of components you have, the more complex things you can build. 

The same logic seems to apply to viruses.  And by reaching Oceania, HPAI H5 has just accessed a fresh supply of new building blocks to play with. 

While what it may eventually create is unknown, we should be prepared for surprises.