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. 

Australia Changes How They Report H5N1 - Tasmania Detects 1st H5 Positive Bird

Credit https://www.agriculture.gov.au/campaigns/birdflu

#19,291

As we discussed a month ago, the number of daily citizen reports of sick or dead birds in Australia was already far outpacing their government's ability to investigate and test carcasses. 

 Graphic generated by Gemini

Yesterday, DAFF announced major changes in how they will report H5N1. No longer will individual detections be announced, instead they will track individual `events'. 

Event reporting

*From 12 August 2026, we have changed how we report on H5 bird flu detections. Reporting will be based on events, rather than individual bird detections, where an event may involve one or more birds. The new number of positive events captures all previously reported individual confirmed detections.

As of 4pm AEST, 13 August 2026, Australia has 186 confirmed events of H5 bird flu in wild birds.

• 10 in Western Australia (WA)
• 123 in South Australia (SA)
• 4 in New South Wales (NSW)
• 1 in Queensland (QLD)
• 48 in Victoria (VIC).

As H5 bird flu is confirmed in more locations and species in Australia it will not be necessary to continue testing all species in known areas of transmission, or to test every bird involved in an investigation. Reporting will be targeted to provide a clear picture of the national H5 bird flu situation in wildlife in Australia and key developments.

Definitions

Investigation: An event where one or more wild birds or wild mammals showing signs of H5 bird flu have been reported to state or territory authorities and samples have been collected for laboratory testing.

Positive event: An investigation where H5 bird flu has been confirmed through laboratory testing.

Negative event: An investigation where laboratory testing has ruled out H5 bird flu.

Hotline report: A report to relevant state or territory authorities through the Emergency Animal Disease Hotline or other official sources.

Disclaimer

Data reflects information provided by state and territory governments to the Australian Government as at 17:00 AEST daily. The Australian Government publishes this information for national reporting purposes. Responsibility for the accuracy, completeness and currency of the data remains with the relevant state or territory government. Due to differences in reporting timing, information on the national dashboard may differ from information published on state or territory government websites.

 

While it is always disappointing to get less precise data, with the number of citizen reports (n=18,869) now running 13 times higher than the number of completed investigations (n=1459), something had to give. 

It isn't clear how this change will affect individual state and territorial reporting, as this new format hasn't yet appeared on either the Victoria or South Australia bird flu update web pages. 

Meanwhile, Tasmania has reported its first local positive detection of H5 in a brown skua. Samples have been sent to CSIRO for confirmation and subtyping.

This from NRE Tas.

H5 bird flu detected in Tasmania

​The Department of Natural Resources and Environment Tasmania (NRE Tas) has detected H5 avian influenza (bird flu) in a wild brown skua.

The bird was identified through NRE Tas surveillance efforts near Rocky Cape in the state’s north west and sent for testing at the Animal Health Laboratory in Launceston.

Following the initial positive test result, samples have been sent to the CSIRO’s Australian Centre for Disease Preparedness in Geelong to confirm the positive detection.

This is Tasmania’s first positive detection in a wild bird. There have been no detections in poultry and there is no evidence of other species mortalities at this time.

Tasmania has been preparing for the arrival of H5 bird flu, working with other government agencies, stakeholders and the community, and is well prepared to respond.

NRE Tas will expand planned surveillance in and around the detection area, including King and Flinders islands. This will include further wildlife monitoring, sample collection and risk assessment activities.

Tasmania has a robust biosecurity system but it is not possible to stop infected wildlife from entering Tasmania.

The Tasmanian Avian Influenza Readiness and Response Plan sets out how NRE Tas will respond to an outbreak of H5 bird flu, and how you can prepare.

In the event of an outbreak, our response will also be guided by the Animal Health Australia AUSVETPLAN response strategy for avian influenza. AUSVETPLAN contains the nationally agreed approach for responding to emergency animal disease incidents in Australia.

Tasmania is also actively advancing vaccination for captive Orange-bellied Parrots as an additional protection measure for this endangered species however vaccination is not practical for most wild bird populations.

There is no approved vaccine in Australia for backyard, domestic or commercial poultry and birds. There is also no vaccine available for seals, dolphins and Tasmanian devils. The Australian Government is working to make new vaccines available and ensure they are safe for use.

For now, H5N1 has not been detected in poultry, livestock, or non-avian wildlife.  But the odds that status quo will last are slim. Hopefully Australia is working on new and better ways to effectively communicate this rapidly evolving crisis to its public, and the world. 

A little over 2 weeks ago we looked at a preprint by Raina MacIntyre et al. (HPAI H5N1 risk in Australia: a model for the prediction of poultry outbreaks) which included a map showing current HPAI H5 detections overlaying poultry production zones.

 

You can still view an updated interactive map at EPIWATCH, which shows the continued encroachment of HPAI in wild birds to these sensitive regions.

  

J. Virology: Risk assessment of avian influenza A(H5N5) virus from the first human case using the ferret model

Credit: Multiple transatlantic incursions of HPAI
clade 2.3.4.4b A(H5N5) virus into North America
and spillover to mammals

#19,290

Last November we saw the first, and as far as we know - only - human infection with emerging H5N5 subtype of avian flu in a resident of Washington State who had contact with backyard poultry and/or wild birds. 

We've been following HPAI H5N5's spread in birds and small mammals - first in Europe, then in Canada and the United States - for several years, including a report last month; Preprint: HPAI H5N5 in a Polar Bear and Atlantic Walrus, Svalbard, 2026, with Widespread Seroconversion in Polar Bears.

In late July we saw a Preprint: A lethal human H5N5 influenza virus isolate exhibits low pandemic risk traits, which somewhat reassuringly found the virus displayed relatively low pandemic risk traits:

• It replicated relatively poorly (compared to seasonal H1N1) in upper respiratory cell cultures, 
• It has a more avian-like pH inactivation point (about 5.5)  compared to human-adapted flu strains
• And - unlike in the Erdelyan et al. study (which reported rapid 100% mortality and some transmission in ferrets) - they reported that  infected ferrets did not infect healthy co-housed ferrets.

Today we've a study published in the Journal of Virology by researchers at the CDC's Influenza Division, NCIRD, which is slightly less reassuring. 

• While they still found no evidence of airborne transmission in the ferret model, they report limited direct-contact transmission in 2 of 3 co-housed ferrets. 

• And while the preprint reported moderate disease severity in ferrets, today's study reports uniformly severe/fatal disease, with rapid systemic spread. 

• And where the preprint characterized WA/2148 as having reduced replication in human bronchial epithelial cultures, the CDC study instead found robust replication in polarized Calu-3 airway cells at both 33°C and 37°C. 

There were differences in both the methods and materials used in these two studies, which could account for these disparities. Today's study even notes that primary human airway cultures or organoids would provide a more physiologically relevant comparison than the proxies used by these two studies.

And as always, the caveat remains that we can only draw limited conclusions from the evaluation and characterization of a single isolate, since even minor differences between strains or genotypes can make significant changes to its behavior.

Due to it length, and technical nature, I've only reproduced the abstract and some excerpts from the study below.  Follow the link to read it in its entirety.  I'll have a brief postscript after you return.

Risk assessment of avian influenza A(H5N5) virus from the first human case using the ferret model
Authors: Joanna Pulit-Penaloza , Jessica A. Belser, Nicole Brock, Troy J. Kieran, Claudia Pappas, Hui Zeng, Xiangjie Sun, Juan A. De La Cruz, Yasuko Hatta, Han Di, C. Todd Davis , Taronna R. Maines 
https://doi.org/10.1128/jvi.00856-26
 
PDF/EPUB

ABSTRACT

The incursion of Eurasian-origin genotype A6 A(H5N5) virus into North America expanded the genetic diversity among North American highly pathogenic avian influenza viruses and heightened concern about zoonotic risk. Following a fatal human infection with the A(H5N5) virus A/Washington/2148/2025, viral replication was assessed in polarized human bronchial epithelial cells, and pathogenicity, transmissibility in direct contact and respiratory droplet models, and airborne virus shedding were evaluated in ferrets to inform pandemic risk assessment.

A(H5N5) displayed robust replication in Calu-3 cells at 33°C and 37°C, showing kinetics and peak titers comparable to those of contemporary genotype B3.13 and D1.1 A(H5N1) viruses. In ferrets, A(H5N5) replicated efficiently in the respiratory tract, disseminated to extrapulmonary tissues, and caused fatal disease in all inoculated animals. Airborne transmission was not observed, and infrequent, low-level detection of virus in air samples paralleled that of A(H5) viruses that are not transmissible via air in ferrets.

In a direct contact model, limited transmission was detected within 4 days of exposure, with evidence of lower respiratory tract replication in contact animals. These findings indicate that the A(H5N5) virus has the capacity for robust replication in an airway epithelial cell line and can cause severe systemic infection and mortality in ferrets but has not acquired adaptations for airborne spread in mammals. Collectively, these results underscore heterogeneity among clade 2.3.4.4b A(H5Nx) viruses in North America and the need for genotype-by-genotype evaluation of newly emerged viruses to understand public health risk.

IMPORTANCE

The emergence of Eurasian-origin genotype A6 highly pathogenic avian influenza A(H5N5) virus in North America has increased viral diversity and raised concerns about zoonotic and pandemic risk. In this study, we evaluated the replication kinetics, pathogenesis, and transmission of A/Washington/2148/2025 A(H5N5) virus, which was isolated from the first reported human infection with this influenza virus subtype, using polarized human bronchial epithelial cells and the ferret model. 

The A(H5N5) virus replicated efficiently in vitro at temperatures representative of the upper and lower respiratory tracts and caused fatal systemic disease in inoculated ferrets. Limited transmission was observed during 4 days of direct contact. Airborne virus detection was infrequent and did not result in airborne transmission. These findings show that A(H5N5) virus can replicate robustly in mammalian cells and cause severe disease but lacks adaptations supporting efficient airborne spread, informing assessment of the pandemic risk posed by genotype A6 influenza viruses.

        (SNIP)

DISCUSSION

The rapid expansion of clade 2.3.4.4b A(H5N1) influenza viruses into novel mammalian hosts has necessitated comprehensive risk assessments of representative viral isolates from different genotypes associated with human infection and detections in mammalian hosts (19, 20).

Collectively, these studies have revealed that clade 2.3.4.4b A(H5N1) viruses can replicate efficiently in a diversity of mammalian epithelial cell types derived from the human respiratory tract (21–23), cause severe and fatal disease in animal models, and have varied capacity for airborne transmission to susceptible contacts (4–6, 18, 24).

 

The detection of A(H5N5) virus associated with fatal human disease in 2025 underscores the confounding unpredictability of A(H5) viruses, and their continued threat to human health.

       (SNIP) 

Overall, the WA/2148 A(H5N5) virus showed the capacity to cause severe, systemic mammalian infection and robust replication in polarized human airway epithelial cells, characteristics similar to those of other contemporary A(H5Nx) viruses. However, the virus lacked clear adaptation for efficient airborne spread, indicating limited adaptation to a mammalian host. Our findings underscore substantial heterogeneity in pathogenesis and transmission among clade 2.3.4.4b A(H5Nx) viruses, supporting continued genotype-by-genotype evaluations.

       (Continue . . .)

As a pandemic virus, H5N5 may not be ready for prime time, but as a zoonotic threat it already appears to be capable of robust replication in human airway cells and causing severe systemic disease in mammals.

All of which makes it a virus very much worth our continued attention. 

Kent County MI Health Department Bulletin on Swine Flu (in pigs) at Local Fair

Credit Wikipedia


#19,289

We've seen an unusually quiet year of reporting on Swine Variant Influenza, with only 2 H1N2v (human) cases reported since October 1st of 2025; a far cry from the average of 36 human infections per year since tracking began in 2011 (n=581). 

The CDC describes swine influenza viruses as: 

• Swine influenza is a respiratory disease of pigs caused by type A influenza viruses that regularly cause outbreaks of influenza in pigs.
• Influenza viruses that commonly circulate in swine are called “swine influenza viruses” or “swine flu viruses.”
• Like human influenza viruses, there are different subtypes and strains of swine influenza viruses.
• The main swine influenza viruses circulating in U.S. pigs in recent years have been, swine triple reassortant (tr) H1N1 influenza virus, trH3N2 virus, and trH1N2 virus.

When a swine influenza virus spills over into a human, it is called a swine-variant virus. The CDC's IRAT (Influenza Risk Assessment Tool) 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

While no additional cases have been confirmed, this week the Kent County Health Department announced the closure of their county fair's swine barn after the sudden death of a pig, and `several other pigs developed signs of illness'. 

KCHD is reportedly investigating reports of `influenza-like' illness among individuals who had contact with pigs at the fair, but no confirmed human infections have been reported at this time.

They are urging the public:

“Anyone who develops flu-like symptoms after having contact with pigs at the fair should contact the Kent County Health Department and let their health care provider know about their exposure.”

So far, we've no indication of the subtype involved or the severity of the human `influenza-like' illnesses they are investigating. Typically, swine variant infections are mild or moderate in humans, with only a couple of deaths reported since 2011. 

The bulletin advises that the Kent County Fair has ended, but attendees who had contact with pigs at the fair should monitor for flu-like symptoms for 10 days.  They then go on to list the precautions other fair-goers in Michigan should take when attending agricultural events. 

First, the Health Department announcement, after which I'll have a bit more.

Health Officials Raise Awareness Following Swine Flu Detection in Pigs at the Kent County Youth Fair

 

GRAND RAPIDS, MI. (August 10, 2026) — The Kent County Health Department (KCHD), in partnership with the Michigan Department of Health and Human Services (MDHHS) and the Michigan Department of Agriculture and Rural Development (MDARD), is advising people who may have had contact with pigs at the Kent County Youth Fair to monitor for influenza-like symptoms due to a detection of swine influenza.

On Friday, August 7, a pig at the Kent County Youth Fair died suddenly, and several other pigs developed signs of illness. The sick pigs were isolated, and the swine barn was immediately closed to the public. However, as a precaution, the KCHD is investigating reports of influenza-like illness among individuals who had contact with pigs at the fair.

“While we do not have confirmation of human infection at this time, we are taking this situation seriously and want people who may have been exposed to know what symptoms to watch for and what to do next,” said Kent County Health Department Health Officer Dr. Adam London.

“Anyone who develops flu-like symptoms after having contact with pigs at the fair should contact the Kent County Health Department and let their health care provider know about their exposure.”

Signs and Symptoms in Humans

Symptoms of swine flu can be similar to the seasonal flu and may include:

• Fever
• Lethargy (tiredness)
• Lack of appetite
• Coughing
• Runny nose
• Sore throat
• Eye irritation
• Nausea
• Vomiting
• Diarrhea

Anyone who had contact with pigs at the fair should monitor for these symptoms for 10 days. Those who develop symptoms should contact their healthcare provider or their local health department for testing. The KCHD Communicable Disease Unit can be reached at 616-632-7228.

Protecting Animal and Human Health at the Fair

While the Kent County Youth Fair has ended, people who plan to attend other agricultural fairs or have contact with animals should take the following precautions to reduce the risk of influenza and other diseases that can spread between animals and people:

• Avoid interacting, touching, or petting animals if you have an increased risk for severe influenza complications.
• Don't eat, drink, or put anything in your mouth in areas with animals.
• Don't take toys, pacifiers, cups, baby bottles, strollers, or similar items into areas with animals.
• Wash your hands with soap and water before and after exposure to pigs or other animals, using hand-sanitizer if water and soap are not available.
• Change and wash clothing and clean footwear or equipment after visiting animal areas, particularly if you have livestock at home.
• Avoid close contact with animals that appear sick, including animals showing loss of appetite, fever, tiredness, eye redness, discomfort, coughing, or a runny nose.
• If you must come in contact with animals that may be ill, then wear personal protective equipment (PPE). This includes protective clothing, gloves, and a well-fitting mask that covers your mouth and nose and immediately contact the fair veterinarian. Parents and caregivers should review considerations for specific groups of people when selecting a respirator or mask for children.
• Stay home and away from others, including animals, if you are experiencing flu-like symptoms

Pork Remains Safe to Eat 

Swine flu in pigs is not a food safety concern, and people cannot contract influenza by eating properly handled and cooked pork or pork products. Consumers should continue to follow standard food-safety practices when handling and preparing pork.

For more information about preventing swine flu, please visit the Centers for Disease Control and Prevention (CDC) website.

This isn't just an American problem, as there is much diversity among swine flu viruses around the globe, with China's EA H1N1 `G4' virus often cited as the biggest pandemic threat. We've also followed repeated spillovers in Brazil, and last year the Eurasian 1C Swine Influenza A Virus was labeled a `high pandemic risk'.

The reality is, surveillance and testing for swine influenza A viruses is notoriously sub-optimal, and many strains circulate under the radar.  

For more on the risks of exposure to influenza infected pigs, you may wish to revisit:

Preprint: Occupationally Exposed & General Population Antibody Profiles to Influenza A Viruses Circulating in Swine as an Indication of Zoonotic Risk