Preprint: Efficient Replication of Influenza D Virus in the Human Airway Underscores Zoonotic Potential

Credit NIAID

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One of the more intriguing influenza discoveries of the past dozen years has been the identification of a previously unknown type of flu - Influenza D - infecting swine, cattle, and apparently even humans.

We first learned of this new flu early in 2013 when researchers reported finding a novel influenza virus in swine from Oklahoma - initially classified as a novel Influenza C virus - but which would later be designated as Influenza D. 

Their research – published PLoS Pathogens – was called Isolation of a Novel Swine Influenza Virus from Oklahoma in 2011 Which Is Distantly Related to Human Influenza C Viruses, and it immediately caused a stir in the flu research community.

The authors found that this new (provisional) influenza C virus could infect, and transmit, in both ferrets and pigs. The following year, in mBio: Characterizing A Novel Influenza C Virus In Bovines & Swine, cattle were added to the list, and identified as the virus's primary reservoir.

Over time the virus was reclassified as `Influenza D', and researchers found evidence of a much wider spread of this virus than just in the American Midwest. (see EID journal’s Influenza D Virus in Cattle, France, 2011–2014 and EID Journal: Influenza D In Cattle & Swine – Italy).

And while it isn't known if Influenza D can cause symptomatic illness in humans, in 2016's Serological Evidence Of Influenza D Among Persons With & Without Cattle Exposure, researchers reported finding a high prevalence of antibodies against Influenza D among people with cattle exposure. 

They wrote:

IDV poses a zoonotic risk to cattle-exposed workers, based on detection of high seroprevalence (94–97%). Whereas it is still unknown whether IDV causes disease in humans, our studies indicate that the virus may be an emerging pathogen among cattle-workers.

Since then, we've revisited Influenza D research often, including these recent posts.

EID Journal (Perspective): Emerging Respiratory Virus Threats from Influenza D and Canine Coronavirus HuPn-2018 

EID Journal: Influenza D Virus in Domestic and Stray Cats, Northern China, 2024)

Today we've a preprint with an excellent pedigree (by researchers from Ohio State University,  St. Jude Children's Research Hospital, and the Abigail Wexner Institute) which provides even more reasons to continue to track this emerging influenza type. 

Not only did they find that influenza D replicates efficiently in the human respiratory tract, they discovered it did not set off the innate immune system's `alarm bells' (interferon and ISG signaling) to the extent that influenza A typically does.

For now, Influenza D appears to produce a muted immune response in humans, which likely explains its extremely mild or subclinical presentation. This stealthy behavior, however, gives it more opportunities to spread unnoticed while potentially better adapting to human hosts. 

I've just reproduced the abstract and a brief excerpt from the preprint. Follow the link to read it in its entirety.  I'll have a bit more after the break.

Efficient replication of influenza D virus in the human airway underscores zoonotic potential
Christina G Sanders, Min Liu, Jovanna A Fusco, Elizabeth M Ohl, Natalie N Tarbuck, Emily M King, Devra Huey, Thomas P Fabrizio, Phylip Chen, Amanda R Panfil, Richard J Webby, Mark E Peeples, Andrew S Bowman, Cody J Warren
doi: https://doi.org/10.64898/2026.02.07.704474
This article is a preprint and has not been certified by peer review [what does this mean?].
 
Preview PDF

Abstract

Influenza D virus (IDV), primarily found in livestock species, has demonstrated cross-species transmission potential, yet its threat to humans remains poorly understood. Here, we curated a panel of IDV isolates collected during field surveillance from 2011 to 2020 from swine and cattle to assess their ability to infect human airway cells as a proxy for zoonotic threat assessment.

Using lung epithelial cell lines, primary well-differentiated airway epithelial cultures, and precision-cut lung slices, we demonstrated that IDV efficiently propagates in cells and tissues from the human respiratory tract, reaching titers comparable to human influenza A virus (IAV).

Infection kinetics in primary porcine airway cultures and respiratory tissues mirrored those from human, suggesting similar infectivity across species.

To define host responses to IDV infection, we evaluated innate immune sensing and downstream interferon signaling in human respiratory cells. IDV infection resulted in markedly reduced activation of interferon regulatory factor (IRF) signaling and diminished induction of interferon lambda 1 and interferon-stimulated genes compared to IAV, indicating inefficient activation of innate immune sensing pathways.

However, IDV replication was potently restricted in interferon-pretreated cells, demonstrating sensitivity to interferon-mediated antiviral effector mechanisms once an antiviral state was established.

Together, these findings show that IDV can efficiently infect the human airway while limiting innate immune sensing, a feature that may facilitate zoonotic spillover. Our study highlights the need for enhanced surveillance of IDV at the animal-human interface and provides a foundation for further investigation into its biology and potential for causing human infection and disease.

        (SNIP)

Taken together, our findings indicate that IDV can infect and replicate efficiently in human respiratory tissues with minimal innate immune restriction. Although human infections documented so far appear subclinical, published studies demonstrate that IDV transmits efficiently among mammalian hosts—including airborne transmission between ferrets (49)— suggesting that the virus already possesses several traits compatible with respiratory spread in humans.

While our study did not directly evaluate the evolutionary steps required for sustained human-to-human transmission, these observations raise important questions about the degree of additional adaptation needed.

This uncertainty underscores the importance of intensified surveillance and mechanistic studies that define the viral and host determinants of IDV transmissibility. What appears today as a quiet livestock virus could, with little warning, ignite the next influenza pandemic. 

        (Continue . . . )

IDV is not detected by routine human influenza surveillance programs, and while some research is underway (see Novel Influenza D Virus Vaccine Strategy) there are currently no vaccines available for humans or animals.

Admittedly the zoonotic potential of Influenza D appears to be low right now, but that could change over time. Like influenza A viruses, influenza D and C viruses have segmented RNA genomes, which allows for reassortment.

The  discovery of frequent reassortment between IDV clades D/660 and D/OK, along with spillovers into new hosts (like dogs and cats), makes influenza D a virus very much worthy of our attention.

More Than One Way To Start An Epidemic . . .

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Last week, in Taiwan: Another Avian Flu `Incident', we looked at the latest in a series (see here, here, and here) of high profile illegal (avian or swine) vaccine smuggling and/or manufacturing operations detected by Taiwanese officials. 

Counterfeit vaccines are particularly worrying, since they may exacerbate existing epizootic threats, but they are far from the only imported zoonotic threats. 

There is a huge global trade in both illegal bushmeat, and in smuggled wildlife, both of which can transport infectious diseases into new regions of the world. Just yesterday Hong Kong Customs reported their seizure of more than 100 wild birds at one of their border crossing points with the Mainland. 

Hong Kong Customs seizes suspected illegally imported live birds (with photo)

 

Hong Kong Customs today (February 7) detected a suspected case of illegal importing of live bird at the Lo Wu Control Point. 112 live birds with an estimated market value of about $15,000 were seized.

Customs officers today intercepted an incoming 26-year-old female passenger at the arrival hall of the said control point. Upon examination, 112 live birds contained in bird cages were seized from the trolley she carried, and she was subsequently arrested.

The case was handed over to the Agriculture, Fisheries and Conservation Department for follow-up investigation.

Under the Public Health (Animals and Birds) Regulations, it is an offence to import any bird unless it is accompanied by a valid health certificate. The maximum penalty upon conviction is a fine of $25,000.

Members of the public may report any suspected activities of illegal import of live birds to Customs' 24-hour hotline 182 8080 or its dedicated crime-reporting email account (crimereport@customs.gov.hk) or online form (eform.cefs.gov.hk/form/ced002).

Ends/Saturday, February 7, 2026

The most obvious concern is of accidentally importing avian flu, which has happened before:

Vienna: 5 Smuggled Birds Now Reported Positive For H5N1

Taiwan Seizes H5N1 Infected Birds

Bulgarian NVS: Confirmed Avian Flu In 2 Illegally Transported Birds

But avian flu isn't the only concern, as we've seen literally dozens of reports over the years of `parrot fever' (see China: Media Reports Of A Psittacosis Outbreak (Parrot Fever) in Zhejiang Province) outbreaks in Asia and in Europe.

The United States famously saw a national panic over `Parrot Fever' in 1929 (see How Parrot Fever Changed Public Health In America), with many fearing a return of the 1918 pandemic.

We've seen horrific examples of the lengths that some people will go to in order to illegally import live birds, including in 2010, when two men were indicted for attempting to smuggle dozens of song birds (strapped to their legs inside their pants) into LAX from Vietnam. 

Sadly, many of the birds did not survive the plane trip.

 Last December Interpol reported on their enforcement efforts in 2025, reporting:

30,000 live animals seized in global operation against wildlife and forestry crime

11 December 2025

134 participating countries make record seizures of protected plants, animals and timber

LYON, France — A global operation against the illegal trafficking of wild fauna and flora has led to the seizure of nearly 30,000 live animals and the identification of 1,100 suspects.

From 15 September – 15 October, law enforcement agencies comprising police, customs, border security and forestry and wildlife authorities from 134 countries made a total of 4,640 seizures during Operation Thunder 2025. This record number of seizures included tens of thousands of protected animals and plants and tens of thousands of cubic metres of illegally logged timber, as well as more than 30 tonnes of species classified as endangered under the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).

Coordinated by INTERPOL and the World Customs Organization (WCO), with the support of the International Consortium on Combating Wildlife Crime (ICCWC), the operation sought to intercept and seize illegally traded wildlife and forestry commodities across the global supply chain and identify, disrupt and dismantle criminal networks involved in these types of environmental crime.

(SNIP)

While live animal seizures reached a record high this year — driven largely by demand for exotic pets — most wildlife trafficking involved animal remains, parts and derivatives, often used in traditional medicine or specialty foods.

Estimates put the annual value of wildlife crime at USD 20 billion, but the clandestine nature of the trade suggests that the real figure is likely much higher.

        (Continue . . . )

The full report is very much worth reading in its entirety (but warning, some of the photos are hard to look at . . ).

In the summer of 2010 headlines were made when a study – published in the journal Conservation Letters looked at the amount of smuggled bushmeat (est. 5 tons a week) that was coming into Paris's Charles de Gaulle airport over a 17 day period on flights from west and central Africa. 

Not all cases of smuggling are part of elaborate criminal conspiracies, sometimes it's just a traveler trying to bring a bit of `home' back to the United States. 

In May of 2013, in All Too Frequent Flyers, we saw a Vietnamese passenger, on a flight into Dulles Airport, who was caught with 20 raw Chinese Silkie Chickens in his luggage. 

But in some cases, illegal imports are being done on a commercial scale, as evidenced by the next two reports which came during the height of China's ASF epidemic. 

• In 2022's USDA/APHIS Seize Nearly 1 Ton Of Illegal Pork Products in NYC Imported From China

• In 2019 (see Feds Seize 1 Million Pounds of Illegal Chinese Pork Products In New Jersey).

Much of the global spread of ASF over the past 15 years has been attributed to careless or illegal transport of contaminated products, making this a serious and ongoing concern. 

An infamous example of the potential zoonotic risks, in 2003 the United States experienced a multi-state (Illinois, Indiana, Kansas, Missouri, Ohio, and Wisconsin) outbreak of Monkeypox when a Texas animal distributor (legally) imported hundreds of small animals from Ghana, which in turn infected prairie dogs that were subsequently sold to the public (see MMWR Update On Monkeypox 2003).

By the time that outbreak was quashed, the U.S. saw 37 confirmed, 12 probable, and 22 suspected human cases. Among the confirmed cases 5 were categorized as being severely ill, while 9 were hospitalized for > 48 hrs; although no patients died (cite).

At roughly the same time the United States was dealing with Monkeypox, Asia, Canada, and the rest of the world were dealing with another zoonotic threat; the first SARS-CoV outbreak (see SARS and Remembrance).

That outbreak was linked to the practice of serving exotic animals - including masked palm civets (and possibly raccoon dogs) - in `wild flavor' restaurants (see A Hong Kong Civets Lesson).

China and the United States (along with many other countries) have since  tightened up their laws and regulations regarding the importation, or consumption, of many of these exotic animals, but the evidence suggests that better laws haven't proven to be an effective deterrent. 

All reasons while increased vigilance is needed if we are to prevent the next global (human or agricultural) infectious disease crisis. 

NERC: Long-Term Reliability Assessment (Jan 2026)

 

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NERC, or the North American Electric Reliability Corporation,  was tasked with "ensuring the reliability of the North American bulk power system" in 2006 following the 2003 Northeast blackout which affected more than 50 million people in the United States and Ontario, Canada.

Over the years we've looked at a number of their summer and winter reliability reports (see The NERC 2025-2026 Winter (Electrical Grid) Reliability Assessment) and their drills and exercises (see GridEx 2013 Preparedness Drill), amid growing governmental concerns over the reliability of the electrical grid (see NIAC: Surviving A Catastrophic Power Outage).

Previously, the biggest threats to the grid were thought to be natural disasters (hurricanes, ice storms, severe space weather, etc.), `bad actors' (cyber-threats, sabotage, etc.), or aging infrastructure (see ASCE report card on America’s infrastructure). 

But the recent and rapidly increasing power demands from A.I. data centers have added yet another potential failure point. 

Last summer's the U.S. Department of Energy published a 73-page report that warned that if current schedules for retirement of reliable power generation (especially baseload) continue, without enough firm replacement, the risk of blackouts in 2030 could increase by 100× over current levels.

Number one on their Key Takeaways is:

Status Quo is Unsustainable. The status quo of more generation retirements and less dependable replacement generation is neither consistent with winning the AI race and ensuring affordable energy for all Americans, nor with continued grid reliability (ensuring “resource adequacy”). 

Absent intervention, it is impossible for the nation’s bulk power system to meet the AI growth requirements while maintaining a reliable power grid and keeping energy costs low for our citizens.

To this growing chorus we can add a 181-page NERC Long-Term Reliability Report - published in January - which also warns that our power grid is facing a growing risk of electrical shortfalls over the next decade.

For those wanting a brief summary, NERC has published the following press release (see Resource Adequacy Risks Intensify Across North America as Demand Growth Surges).

January 29, 2026

WASHINGTON, D.C. – NERC’s 2025 Long-Term Reliability Assessment (LTRA) and infographic spotlight intensifying resource adequacy risks throughout the North American bulk power system (BPS) over the next 10 years. Summer peak demand is forecast to grow by 224 GW, a more than 69% increase over the 2024 LTRA forecast with new data centers for artificial intelligence and the digital economy accounting for most of the projected increase.

Winter demand growth continues to outpace summer demand growth with 246 GW of growth forecast over the next 10 years, reflecting the evolution of electricity usage. Uncertainty and lag in the pace of new resource additions are driving heightened concerns that industry will not be able to keep up with rapidly increasing demand.

       (Continue . . . )

Some brief excerpts from the executive summary include:

Executive Summary

The overall resource adequacy outlook for the North American BPS is worsening: In the 2025 LTRA, NERC finds that 13 of 23 assessment areas face resource adequacy challenges over the next 10 years. Projections for resource and transmission growth lag what is needed to support new data centers and other large loads that drive escalating demand forecasts. 

Most new resources in development to come on-line in the next five years consist of battery storage and solar photovoltaic (PV), which are inverter-based and weather-dependent resources that increase the complexity of planning and operating a reliable grid. Meanwhile, more fossil-fired generator retirements loom in the next five years, reducing the amount of generation that has fuel on site and impacting the system’s ability to respond to spikes in demand. 

The continuing shift in the resource mix toward weather-dependent resources and less fuel diversity increases risks of supply shortfalls during winter months. As Resource Planners, market operators, and regulators grapple with steep increases in demand and swelling resource queues, they face more uncertainty, adding to the already-complex endeavor of planning for resource adequacy during this period of rapid grid transformation. 

To ensure there are sufficient resources for supplying electricity in the future and to reliably meet the growing electricity needs for North Americans, industry, regulators, and policymakers need to be vigilant for shifting projections, keep plans for deactivating existing generators flexible, expedite system development, and perform robust adequacy assessments of future scenarios. In addition, careful planning and broad cross-sector coordination will be needed to navigate a period of potentially strained electricity resources.

The findings presented here are vitally important to understanding the reliability risks to the North American BPS as it is currently planned and being influenced by government policies, regulations, consumer preferences, and economic factors. Summaries of the report sections are provided below.

       (Continue . .  )

 
While the tone of this report is cautiously optimistic that the risks going forward are manageable; it stresses that `broad cross-sector coordination will be needed to navigate a period of potentially strained electricity resources.'

The same sort of  broad cooperation that is often called for - but is rarely seen - for mitigating climate change or preventing the next pandemic. 

Hopefully, this time the stakes will be deemed high enough that our collective  response will be different.  

But I'm not planning on selling my solar panels anytime soon.  

Taiwan: Yunlin County Reports Another `Midnight' Dumping of H5N1 Infected Poultry

 

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Last week Taiwan's poultry industry was roiled by the discovery of thousands of H5N1 infected poultry illegally dumped or buried in locations spanning two counties (see Taiwan: The Plot Thickens . . .), while earlier this week Taiwan's APHIA announced the seizure of a large quantity of illegal Chinese poultry vaccines, which were (reportedly) purchased from a Chinese online shopping website.

Given the steep civil and criminal penalties involved in these types of activities, it gives us some idea of how desperate the HPAI situation must be for some farmers in Taiwan.

Today, the Yunlin County Animal and Plant Disease Control Center (YCAPDCC) is reporting a similar incident, involving the illegal dumping of hundreds of H5N1 infected geese into a local fish pond.

First the translated statement from Yunlin County, after which I'll have a bit more.

Bird flu alert! Urges to implement food safety measures, proactive reporting, and severe penalties for concealing or disposing of dead poultry.
Issuing unit: Institute of Zoology and Plant Disease Control

 Yunlin County Government News Reference Material 115.02.06

On February 4, 2016, the Yunlin County Animal and Plant Disease Control Center (hereinafter referred to as the Disease Control Center) received a report that dead poultry (meat geese) had been randomly dumped next to a fishpond in Kouhu Township.

The source farm (Sihu Township) was found to have H5N1 subtype highly pathogenic avian influenza. In accordance with standard operating procedures, 1,626 7-week-old meat geese were culled and destroyed. The Center also supervised the operator to complete the cleaning and disinfection of the farm area.

County Magistrate Chang Li-shan stated that it is currently the peak season for avian influenza, and poultry farmers must not only implement biosecurity measures on their farms but also cooperate with relevant disease prevention measures.

Regarding the farm's indiscriminate disposal and failure to proactively report the outbreak, the county government will, in accordance with the Animal Infectious Disease Prevention and Control Act, not compensate for the losses from culling animals and destroying materials, and will impose a fine of up to NT$1 million. Furthermore, the failure to properly process the dead poultry will also be punished according to the Animal Husbandry Act.

Liao Pei-chih, director of the Disease Control Center, stated that disinfection of public areas will be strengthened at farms where highly pathogenic avian influenza cases have been confirmed and at sites where dead poultry are disposed of. Sampling and site visits will also be conducted at two poultry farms within a 1-kilometer radius to control the risk of disease transmission.

Highly pathogenic avian influenza can spread through migratory birds and then horizontally through the production and sales system. It is imperative for poultry farms to strengthen their own biosecurity measures. Poultry farmers are urged to continue implementing bird-proofing facilities and access control at their farms. All personnel, vehicles, and equipment (including egg boxes and cages) entering the farm must be thoroughly cleaned and disinfected.

Farmers should also be vigilant and monitor the health of their poultry daily. If any abnormalities are found, they should be reported immediately (reporting hotline: 0932-690674) to prevent the spread of the virus and avoid significant economic losses to the industry.

We've often seen this sort of `midnight' dumping in places like China, India, and Vietnam, but it even occurs occasionally here in the United States (see news report Dozens Of Illegally Dumped Dead Chickens In Acton Test Positive For Contagious Avian Disease).  

Note: in this case, the disease was Infectious Laryngotracheitis, or ILT - not avian flu.

The wholesale dumping of ASF infected pigs in China (and elsewhere) likely contributed to the further spread of the disease (see Philippines Ag. Dept. Warns On Illegal Disposal Of Dead Pigs), and there are similar concerns with HPAI.

Soberingly, there is probably a lot more of this illegal activity than we ever hear about.  

South Korea CDC: `Traveler Respiratory Disease Testing Service' Expanded to 13 Airports & Ports Nationwide

 

Translated KCDC Graphic

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South Korea continues to be openly proactive in their preparations for the next pandemic threat:

• Eighteen months ago, in South Korea CDC Releases Revised ‘Influenza Pandemic Preparedness and Response Plan’, warning “In the event of a new or variant influenza pandemic, it can surpass COVID-19”.

• In May of 2025, South Korea partnered with SK Bioscience to develop an Avian Flu Vaccine.

• Last September, in South Korea Conducted A 19-day, Nationwide, Mock-Training Exercise to Prepare for Zoonotic Influenza.

• Last December, South Korea was one of 31 Asian countries to participate in WPRO Table-Top Exercise Crystal: A `Bovine' Novel Flu Outbreak Scenario

• And we are currently watching some of the most aggressive culling and quarantine operations on the planet with with their triple outbreak of HPAI, ASF, and FMD on South Korean farms. 

A year ago, South Korea instituted a voluntary respiratory testing pilot program at two airports (Gimpo and Jeju), which was expanded to 5 more by mid summer.  

Today, based on their success, they are announcing the program will expanded to 13 airports and ports nationwide, starting February 10th.  This comes a week before the Lunar New Year, and the height of the spring travel season. 

While a few other countries (including the United States) have set up limited screening programs in a few select ports of entry, few are as sophisticated or as extensive as the system now in place in South Korea. 

I've reproduced the (translated) KCDC press release below.  I'll have a bit more after the break. 

The "Traveler Respiratory Disease Testing Service" will be expanded to 13 airports and ports nationwide (Friday, February 6).

Date of writing February 6, 2026
Last modified date February 6, 2026
Department in charge Quarantine Policy and
contact 043-719-9216

- The "Traveler Respiratory Disease Testing Service" has been expanded to 13 airports and ports nationwide.

- Free testing will be provided to all arrivals with respiratory infection symptoms starting February 10th.

- Health insurance benefits are applicable when you visit a medical institution with a positive test result.

【Related National Policy Tasks】 84. Eliminate regional disparities, expand essential medical services, and strengthen public health care.

The Korea Disease Control and Prevention Agency (KDCA) (Director Seung-Kwan Lim) will expand the "Traveler Respiratory Infectious Disease Testing Service" to 13 quarantine stations (12 branch offices) at airports and ports nationwide, starting February 10, 2026.

This project has been piloted at Gimpo and Jeju Airports since February 2025, followed by Gimhae Airport (April), Daegu and Cheongju Airports, and Busan and Incheon Ports (July). Based on comprehensive considerations of the operational results, traveler awareness surveys, and on-site conditions, the project will be expanded nationwide.

< Overview of Traveler Respiratory Infection Testing Services >

division

Key Contents

Translated KCDC Graphic

Target audience

Only those who wish to be tested among symptomatic overseas arrivals at the airport and those without epidemiological links

Inspection location

Quarantine station , overseas infectious disease reporting center, etc.

Inspection items

Animal influenza human infection (AI), COVID -19, influenza A/B (3 types )

Inspection method

PCR and genomic analysis of positive samples

< Intention to use ' Free Quarantine Testing ' >

< Reasons for using ' Free Quarantine Testing ' >

Translated KCDC Graphics

Through this project, the Korea Disease Control and Prevention Agency (KDCA) is proactively monitoring new and mutated pathogens entering the country. According to pathogen analysis results from 2025, 18 COVID-19 cases and 53 influenza cases (51 A and 2 B) were detected out of a total of 169 cases. Genomic analysis has identified COVID-19 subtypes (e.g., NB.1.8.1) and influenza subtypes (H1N1, H3N2, B (Victoria)), and ongoing monitoring is underway.

Meanwhile, according to the results of a survey on awareness of quarantine services conducted on 530 adult men and women in their 20s to 60s who have traveled abroad within the past year (November 25), 9 out of 10 respondents (88.9%) expressed their intention to use free quarantine testing if they develop symptoms of an infectious disease at the entry stage, confirming that there is high public demand for quarantine services.

< Results of a survey on awareness of free quarantine testing >

If an inbound traveler with respiratory infectious disease symptoms such as a cough wishes to be tested, he or she can receive free testing for three types of respiratory infectious diseases (COVID-19, influenza A/B, and animal influenza human infection (AI)) at the quarantine station quarantine desk or overseas infectious disease reporting center.

Test results will be individually notified via text message or email. If your test result is positive, you can receive National Health Insurance benefits by visiting a medical institution with a certificate of positive test result issued by the quarantine station.

Lim Seung-kwan, director of the Korea Disease Control and Prevention Agency, said, “Through this nationwide expansion, we plan to strengthen the surveillance system for respiratory infectious diseases imported from overseas and establish a response foundation linked to the domestic infectious disease surveillance system by detecting new and mutated pathogens early.” He also asked, “In particular, if you have respiratory symptoms during the Lunar New Year holiday, please participate in protecting the safety of your family and neighbors by taking a simple test before returning home.”

        (Continue . . . )

 
Long-time followers of infectious disease outbreaks will recall that South Korea was badly burned in the summer of 2015 by an international traveler who arrived from the Middle East carrying MERS-CoV - which subsequently:

• forced the quarantining of > 16,000 people
• the closure of 2,400 schools and 22 Universities
• spread through 17 hospitals
• was confirmed in 186 people (185 in the Republic of Korea and 1 in China),  
• resulting in 38 deaths
• and the loss of billions of dollars

While ultimately contained, this was an early close call with a particularly deadly coronavirus. For more details, see The Lancet: Mapping The Korean MERS-CoV Superspreading Event. 

Which may help explain why South Korea has become so visibly proactive in preparing for the next global health crisis, while so many other countries appear eager to downplay the threat, and hope for the best.

Norwegian Vet. Institute: Update On Avian Flu Detections In Wild Birds

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Although the above map (EFSA Avian Flu Dashboard) is only current through mid-December, it illustrates just how impressive this year's invasion of (mostly) HPAI viruses has been in Europe (note: not all countries test, or report cases). 

While we await further word from the Netherlands on their detection of H5N1 antibodies in dairy cattle, we have the following update from the Norwegian Veterinary Institute, on a recent surge in HPAI H5 detections in wild birds. 

As we've seen in other European countries, H5N1 continues to expand its host range in both mammals and avian species.  I've reproduced the (translated) press release below.

Increased number of detections of avian influenza in swans
Published 05.02.2026

The Norwegian Veterinary Institute has detected an increasing number of cases of avian influenza in wild birds, especially swans, since mid-November 2025. Both mute swans and whooper swans have been affected, and the findings have been made in Trøndelag, Eastern Norway, Southern Norway and Western Norway.

Illustration image: Colourbox

– Swans are among the species that often show clear signs of illness when they get influenza, and there are many people who follow them, so it is quickly caught when they become infected, says Bjørnar Ytrehus, head of wildlife health at the Norwegian Veterinary Institute.

Swans show clear signs of illness

Most of the sick swans have shown clear signs of neurological disease, such as swimming in circles, lying with their heads on the water surface or losing the ability to keep their balance. Sick swans are probably an indicator that there is now a lot of avian influenza virus circulating among wild birds in large parts of Norway, says Ytrehus.

Geese, ducks, birds of prey and seagulls are also affected.

In addition to swans, bird flu has been detected in several species of geese and ducks, as well as some birds of prey and gulls. Several of these birds have also been sick. However, ducks can also be healthy carriers of the infection and contribute to the spread without showing signs of illness.

If there is suspicion of infection with avian influenza in birds and other animals, the Norwegian Food Safety Authority must be notified.

The same virus variant dominates in Europe

It is the same variant of the H5N1 virus that caused a strong increase in infections in wild birds in Europe this autumn, which now also dominates in Norway. Several other European countries have also reported increased infections in ducks in recent months. In Europe, there have also been many outbreaks of bird flu in poultry and hobby birds during this period, while in Norway we had the last outbreak in September 2025.

See an overview of previous outbreaks in poultry in Norway.

– A high infection pressure among wild birds emphasizes the importance of maintaining good infection control in commercial poultry farms and hobby bird keeping throughout the country to avoid the introduction of infection, says Grim Rømo, head of poultry at the Norwegian Veterinary Institute.

Can also infect other animals

Bird flu can be transmitted from wild birds to mammals, and in rare cases to humans. From 2022 to now, bird flu virus has been detected in 18 wild mammals in Norway. See an overview of cases in mammals on the Norwegian Veterinary Institute's website.

– If sick or dead birds are found, they should not be touched, emphasizes Ytrehus. Such birds should only be handled by trained personnel with appropriate infection control equipment. Dogs and cats should also be kept away from sick and dead birds.

More information and advice about bird flu can be found on the Norwegian Food Safety Authority's website.

Monitoring the situation

The Norwegian Veterinary Institute monitors avian influenza as part of its core activity, and also participates together with the Norwegian Institute of Public Health in the EU-funded One Health for Surveillance (OH4S) project. One of the goals of OH4S is to strengthen surveillance of avian influenza in wild birds in order to better assess the risk of infection to humans. Read more on the Norwegian Veterinary Institute's website.

Advice for preventing bird flu infection in humans can be found on the Norwegian Institute of Public Health's website