EID Journal: Serologic Evidence of Avian Influenza Virus Exposure in Livestock, Egypt, 2024–2026

#19,402

In the spring of 2024 a mysterious illness spreading among Texas, Kansas, and New Mexico dairy cattle was identified as avian H5N1, an outbreak that has now spread to at least 21 states, and has affected > 1200 herds.  

At that time cattle were believed poorly susceptible to influenza A (see A Brief History Of Influenza A In Cattle/Ruminants), and so testing for H5N1 was delayed.   

The immediate global reaction was that this was an `American problem', caused by a new (and presumably unique to North America) strain (B3.13) of H5N1 (see DEFRA Risk Assessment Of HPAI H5N1 Occurring in Cattle In the UK), and unlikely to occur in Europe. 

This strain has not been detected in the UK, and none of the viruses detected in the UK over the 2020 to 2024 HPAI outbreak period have contained genetic material originating from North or South American viruses. 

 The risk to GB of H5N1 in livestock is assessed at very low. 

That assumption was challenged in June of 2024 (see Germany: FLI Statement On Experimental Infection Of Dairy Cows With European H5N1 Virus) when researchers demonstrated that a German virus isolate could replicate in a cow's udder after experimental infection.

Over the summer of 2024 the USDA reassuringly suggested that B3.13 entered dairy cattle via a single spillover from birds - and was subsequently spread by the interstate transport of infected dairy cows. That assumption held until early 2025 when another genotype (D1.1) turned up in dairy cattle in two states (Nevada & Arizona).

In March of 2025, the UK's Defra reported H5N1 Detected In Domestic Sheep with Mastitis, and over the previous year we'd seen reports of other non-B3.13 H5N1 in goats and sheep in Pakistan, horses in Mongolia, and pigs in Oregon.

Also in the spring of 2025, Chinese scientists warned that Clade 2.3.4.4b HPAI H5N1 influenza Viruses from Birds in China Replicated Effectively in Bovine cells.

Last April, in Preprint: Infection of the Bovine Mammary Gland by Avian H5N1 Subclade 2.3.4.4b Influenza viruses. we saw even more evidence that diverse HPAI H5 strains could infect dairy cattle. The authors wrote:

Our findings show that mammary tissue from common cattle breeds is permissive to clade 2.3.4.4b H5N1 infection. These results support the view that bovine mammary epithelium represents a susceptible tissue environment and suggest that IAV infection in cattle may be more widespread than previously assumed.

Four months ago, in Eurosurveillance: Detection of antibodies against avian influenza in European dairy cattle, the Netherlands, January 2026), we saw additional evidence of HPAI spillover into dairy cattle outside of the United States. 

A little over a a year ago, WOAH embraced an 11-page OFFLU technical document (see OFFLU Guidelines for High Pathogenicity Avian Influenza Virus Risk Mitigation in Cattle) which - among other things - finally made HPAI in cattle a `reportable disease'.

But surveillance remains passive, and testing largely up to the discretion of the livestock owner. Something that many farmers find unappealing, fearing the quarantining of their herds and the stigma of infection.

Today we've an EID Journal research letter which reports compelling serological evidence not only of HPAI H5 infection in Egyptian cattle, but LPAI H9N2 as well.  The authors write:

Our findings indicate that spillover of avian influenza viruses to cattle and other livestock is not geographically restricted or caused by certain genotypes of H5N1 virus.

Testing included both hemagglutination inhibition (HI) and microneutralization (MN) assays, and positive results weren't confined to cattle.  Sheep and goats tested positive for LPAI H9N2 as well.  

I've only posted some excerpts from this letter. Follow the link to read it in its entirety. I'll have a postscript after the break.

Volume 32, Number 12—December 2026
Research Letter
Serologic Evidence of Avian Influenza Virus Exposure in Livestock, Egypt, 2024–2026

Mokhtar Gomaa, Rabeh El-Shesheny, Ahmed El Taweel, Omnia Kutkat, Hager Emam, Basant Helal, Ayat Swelam, Mohamed GabAllah, Ahmed Kandeil, Pamela P. McKenzie, Richard J. Webby, Mohamed Ahmed Ali, and Ghazi Kayali

Abstract

Spillover of influenza A(H5N1) virus to cattle in the United States sparked global concern. We investigated whether endemic avian influenza viruses are potentially spilling over into domestic livestock in Egypt. We detected influenza H9N2 antibodies in 2.5% and H5N1 antibodies in 2.9%–4.5% of tested animals. Additional surveillance will elucidate host infection dynamics.

       (SNIP) 

Clade 2.3.4.4b H5N1 virus and low-pathogenicity avian influenza A(H9N2) virus are widely and endemically circulating in poultry in Egypt on farms and backyards and at live bird markets (7). Subtype H5N1 was detected in feral rats in poultry production areas (8). In addition, reassortment events between the H5N1 and H9N2 subtypes led to the emergence of novel clade 2.3.4.4b influenza A(H5N2) viruses (9). To determine whether those viruses are spilling over to livestock in Egypt, particularly in mixed-species settings, we conducted a serosurveillance study in northern Egypt.

During October 2024–January 2026, we collected 444 serum samples from 33 conveniently selected small farms (≈10 cattle, no mixed species) and backyards housing cattle (1–3 cattle with mixed species) in 3 governorates (n = 155, n = 59, and n = 230) in northern Egypt, representing common practices in Egypt. Sheep and goats were also sampled if housed in the same backyards as cattle. All sampled animals were apparently healthy adults.

We tested serum samples for antibodies against a 2025 Egyptian clade 2.3.4.4b H5N1 (A/duck/Egypt/BA20361C/2022) virus using hemagglutination inhibition (HI) and microneutralization (MN) assays and against a G1-like Egypt influenza A(H9N2) (A/chicken/Egypt/RA20191OP/2022) virus by HI in accordance with World Health Organization protocols (10). We considered an antibody titer >1:40 as positive for both assays. Data on the number of cows, presence of other mammals (e.g., donkeys and horses), and presence of avian species (poultry and/or wild birds) were available for 271 samples. We performed statistical comparisons with χ2 or Fisher exact tests; we considered p<0.05 statistically significant.

Overall, 11 (2.5%) serum specimens tested positive for influenza A(H9N2) antibodies, 20 (4.5%) were positive for influenza A(H5N1) antibodies by HI, and 13 (2.9%) were positive for influenza A(H5N1) antibodies by MN (Figure, panel A). Positive titers were 40–160 (Figure, panel B). None of the samples tested positive for antibodies against both viruses. Of the 20 H5N1 virus specimens positive by HI, 12 tested positive by MN; 1 specimen was negative by HI and positive by MN. All influenza H9N2-positive specimens were from 3 locations in the same governorate (p = 0.005). Influenza A(H5N1) antibodies were detected in 2 governorates; the differences in detection rates by governorate were statistically significant (0%, 1.3%, and 4.8%; p = 0.049). All H5N1 virus–seropositive specimens were from cattle (Table).

We detected H9N2 antibodies in 6/374 (1.6%) of cattle specimens, 1/31 (3.2%) of goat specimens, and 4/39 (10.3%) of sheep specimens (p = 0.004). Presence of other animals did not predict seropositivity. Small farms had a significantly higher proportion of H5N1 virus–positive animals tested by MN (p = 0.039).

Our findings indicate that spillover of avian influenza viruses to cattle and other livestock is not geographically restricted or caused by certain genotypes of H5N1 virus. Clade 2.3.4.4b H5N1 virus of the EA-2021-AB genotype and G1-like H9N2 virus appear to be spilling over into livestock in Egypt; however, because our evidence is serologic, we could not ascertain whether true infection is occurring and whether the same signs seen in the United States are common in cattle in Egypt. 

Even so, the evidence is a strong indicator that spillover is occurring, similar to that reported in Europe (4,6). Furthermore, spillover is not restricted to cattle; some sheep and goats tested in our study were seropositive for influenza A(H9N2) virus. Surveillance for avian influenza viruses in Egypt and other countries, especially those in which avian influenza is endemic, will verify infection and provide data on frequency, routes of transmission, and factors affecting infection of and transmission to livestock.

       (Continue . . . )
 

Despite the accrued evidence to date -  for a myriad of political, societal, economic, and logistical reasons - governments around the world appear slow to respond to HPAI (and now LPAI) spillover into mammalian livestock.   

We see this same reluctance in investigating HPAI spillover into other species, including farmed mink (see Virological (Referral): Preliminary report on H5N1 highly pathogenic avian influenza in Utah mink, August 2026).

Although this laissez faire approach may work out in the short run, it provides these viruses with ample opportunities to spread, to evolve, and to adapt. 

Admittedly, most of these viruses will likely never pose a serious public health threat. 

But it only takes one overachiever - aided and abetted by inaction on our part - to plunge the world back into another pandemic crisis. 

NOAA Climate Prediction: West Coast Atmospheric River Event (Nov 10th-16th)

 

NOAA Forecast Issued Nov 3rd

#19,401

As we discussed 2 months ago in #NPM26: Preparing For An El Niño Winter, the west coast and the southern tier of states have been warned to expect an unusually wet and stormy winter due to the record Pacific El Niño. 

Predicting exactly where unusual or severe weather will occur this winter   is impossible, but generally, the jet stream across the United States shifts storm tracks to the southern tier of states during an El Niño winter.

Parts of Florida have already seen record flooding in the past week, but it appears that next week Northern California and the Pacific Northwest will be faced with a substantial atmospheric river event; one which could bring heavy rain and snow to much of the west coast. 

 

NOAA's Climate Prediction Center published the following warning yesterday:

Key Messages from the NOAA Climate Prediction Center
Issued November 2, 2026 and Updated November 3, 2026

Atmospheric River Expected to Affect the West Coast States

Atmospheric river activity is expected to pull significant amounts of moisture into much of the West Coast during the second week of November and weekend, with a potential secondary moisture surge later in the period. Strong surface low pressure just north of the region will also likely drive high winds along the immediate coastline.

(a) A moderate risk (40 to 60%) of heavy precipitation and possible flooding is indicated for Nov 11 to 15 across parts of the Pacific Northwest and northern/central California, while a slight risk (20 to 40%) extends to Nov 17 across the West Coast into the Desert Southwest, Great Basin, and Southern Rockies. High winds are possible across much of the West, including a moderate risk along the immediate West Coast Nov 11 to 15 and a broader slight risk extending to Nov 17.

(b) A moderate risk of heavy snow is indicated across the higher elevations of the Klamath and Sierra Nevada Nov 11 to 15. Slight risks of heavy snow extend to Nov 17 for high elevations of the Cascades, Klamath, and Sierra Nevada, as well as the Northern Intermountain, Great Basin, and Central and Northern Rockies.

Monitor local forecasts for safety alerts, avoid driving through flooded roadways, and use caution if traveling through high elevations. Be prepared for power outages due to high winds.

This is likely just the first of many such storms expected to impact the west coast this winter, and inland freshwater flooding is a major concern.  Six weeks ago, in anticipation of these events, California Declared a State of Emergency to Bolster Statewide El Niño Preparedness. 

The LA County website is urging both community and individual preparedness for what is expected to be a difficult winter, and advises:

LA County is preparing its flood control and emergency response systems now. Crews are inspecting and maintaining dams, debris basins, channels, storm drains, and pump stations; monitoring burn areas, hillsides, and other areas at risk of flooding and debris flows; and preparing for evacuations, emergency shelter, and other storm response. County teams are also preparing to assist people experiencing homelessness, older adults, and others who may need additional help during severe weather.

Here’s what residents can do now:

• Sign up for emergency alerts: Go to alert.lacounty.gov to receive emergency notifications, including evacuation warnings and orders.
• Know the risks where you live: If you are near a hillside, canyon, recent burn area, or area that can flood, learn your flood and mudflow risk before a storm.
• Make an evacuation plan: Know where you will go and how you will get there if you need to leave quickly.
• Have supplies ready: Keep enough food, water, medications, and other essentials for up to 10 days.
• Prepare your home: Clear gutters, downspouts, and storm drains, fix roof leaks, and get sandbags before heavy rain is in the forecast.
• Consider flood insurance: Standard homeowners insurance does not cover flood damage. Flood insurance is separate and can take at least 30 days to go into effect.
• Need help with mud or debris flow risk? Call LA County Public Works at 1-800-933-0930 to speak with an engineer.
• Know someone experiencing homelessness who needs help? Visit homeless.lacounty.gov/get-help/

While this first round is expected to impact further north, now is the time for everyone along the west coast - and much of the southern United States - to prepare for severe storms and elevated flood risks. 

Those interested in diving into one of the more extreme (albeit, based on  historic events) scenarios of Atmospheric river flooding may wish to revisit 2022's California's ARkStorm Scenario Revisited & National Preparedness Month, but even a far less severe event could be devastating. 

Whether it's coastal storms,  inland flooding, or ice storms or tornado outbreaks in the southland, El Niño has the potential to adversely affect millions of Americans this winter (and potentially billions worldwide). 

So, if the power goes out today for a week, or if flood waters begin to rise . . . do you already have?

• A battery operated NWS Emergency Radio to find out what was going on, and to get vital instructions from emergency officials
• A decent first-aid kit, so that you can treat injuries
• Enough non-perishable food and water on hand to feed and hydrate your family (including pets) for the duration
• A way to provide light when the grid is down.
• A way to cook safely without electricity
• A way to purify or filter water
• A way to handle basic sanitation and waste disposal.
• A way to stay cool (fans) or warm when the power is out.
• A small supply of cash to use in case credit/debit machines are not working
• An emergency plan, including meeting places, emergency out-of-state contact numbers, a disaster buddy, and in case you must evacuate, a bug-out bag
• Spare supply of essential prescription medicines that you or your family may need
• A way to entertain yourself, or your kids, during a prolonged blackout

If not, you've got some important work to do.

A good place to get started is by visiting Ready.gov, or by hitting this link which will serve up a series of my preparedness blogs.

When Flu Viruses Collide

 

Antigenic `Shift' or Reassortment 

#19,400 

Influenza co-infections in humans - or in any other susceptible host (birds, pigs, cattle, sheep, etc.) - are a public health concern because they can allow two (or more) influenza viruses to swap genetic material (reassort) and produce a hybrid virus.

It's more than just a theoretical concern, as twice in my lifetime (1957 & 1968) a reassortment between seasonal flu and an avian flu virus - possibly in a human host - produced a pandemic virus. 

• The first (1957) was pandemic H2N2, which According to the CDC  emerged after three different genes from an H2N2 avian influenza A virus combined with 5 genes from the existing H1N1 virus.

• In 1968 a novel H3N2 virus emerged (a reassortment  consisting of 2 genes from a low path avian influenza H3 virus, and 6 genes from seasonal H2N2) which continues to spark yearly epidemics more than 58 years later.

While we'll never know exactly where or how these novel viruses came about, the genetic fingerprints of reassortment are unmistakable. This is the reason why yearly flu vaccination has long been recommended for people who raise pigs or work with poultry and the CDC now urges vaccination in dairy workers.

Coinfection is rare, but not unheard of, and as any virologist will tell you; Shift happens.

With three recent dairy-linked H5N1 cases (1 fatal) reported in Washington state - and previous evidence suggesting mild and/or asymptomatic cases may go unreported (see MMWR: Serologic Evidence of Recent Infection with HPAI A(H5) Virus Among Dairy Workers), the arrival of the fall flu season raises concerns over the possibility of seeing a rare coinfection.  

In addition to vaccination, the CDC also promotes (see Reducing Exposure for Workers to Avian Influenza A Viruses) the use of PPEs, but it isn't clear how many are following this advice.

Since 2009, with increased surveillance and better tools, we've seen a growing number of reports of human co-infection with influenza A:

EID Journal: Nosocomial Co-Transmission Of H7N9 & H1N1pdm09

EID Journal: Human Co-Infection with Avian and Seasonal Influenza Viruses, China

Lancet: Coinfection With H7N9 & H3N2

But evidence of the generation of `biologically fit' reassortant viruses from a human co-infection remain rare.

• In 2025's Eurosurveillance: Novel influenza A(H1N2) Seasonal Reassortant Virus Identified in a Patient, Sweden, April 2025 we saw a rare reassortment between seasonal H1N1 and seasonal H3N2.

• In April of 2020, during the opening of the COVID pandemic, we saw an MMWR Report on a Seasonal H3N2 & H1N1pdm09 Reassortant Infection - Idaho, 2019), involving a 13 year-old boy.

• In 2015's J Clin Virol: Influenza Co-Infection Leading To A Reassortant Virus, we looked at co-infection in a Cambodian patient with both seasonal H3N2 and H1N1pdm09 which led to a new, reassortant H3N2 virus.
• And in 2011 we saw a similar co-infection in a 16 month old boy in Canada that led to the creation of a unique hybrid reassorted virus (see Webinar: pH1N1 – H3N2 A Novel Influenza Reassortment).  

In 2024, Chinese scientists looked at the reassortment potential of H5N1 and H3N2 (see Preprint: Intelligent Prediction & Biological Validation of the High Reassortment Potential of Avian H5N1 and Human H3N2 Influenza Viruses) and predicted the risks to be relatively high.

Another, older (2010) study (see PNAS: H3N2 And H5N1 Reassortment) found that Reassortment between avian H5N1 and human H3N2 influenza viruses creates hybrid viruses with substantial virulence.

While it is difficult to judge the probability of H5N1 successfully swapping genes with H1N1, I've not seen any studies that have shown that these viruses cannot reassort.

Of course, reassortment with seasonal flu doesn't have to happen in a human.  Swine, cattle, and other species can be susceptible to both human and avian flu. 

Just a few of many scenarios

While no one can predict whether H5Nx and seasonal flu will ever hook up and produce a viable threat, there is historical precedence. Which makes anything we can reasonably do to reduce that risk worth doing. 

Simple things; like getting the seasonal flu vaccine, wearing PPEs when in high-risk contact with dairy cattle and poultry, and not consuming raw milk could go a long way in reducing those risks. 

Of course, whether we can be bothered to take these types of proactive steps, remains to be seen. 

Preprint: H5N5 virus transmission is driven by repeated cross-Atlantic introductions and transmission among high latitude seabirds

 

#19,399

While most of the world's avian flu attention is focused on HPAI H5N1, in northern Europe, Iceland, and parts of Canada, a different variant - HPAI H5N5 - has been making substantial inroads in recent years, killing birds and spilling over into cats, foxes, seals, and racoons.  

In 2024's Cell Reports: Multiple Transatlantic Incursions of HPAI clade 2.3.4.4b A(H5N5) Virus into North America and Spillover to Mammals, we saw evidence of multiple introductions of H5N5 into North America, most likely by pelagic seabirds.

While only rarely reported in U.S. birds (just 58 out of 20,539 USDA samples), last November H5N5 infected and killed a resident of Washington State following contact with backyard birds.

Last March, in Viral Creep: H5N5 Update, we looked at its evolution as it has spread across the United States; shifting from almost exclusively EA H5N5 prior to last fall, to largely EA/AM H5N5 since November 2025.

 

Based on USDA Data - Graph created with Gemini

The USDA defines these two strains as:

EA = Eurasian; AM = North American; the EA H5 (2.3.4.4) viruses are highly pathogenic to poultry.

EA/AM: reassortant of H5 goose/Guangdong and North American wild bird lineage

Over the past summer, once again we saw several reports (see here,  here and here) of H5N5 in land mammals (polar bears, foxes, walruses) above the arctic circle. 

Although its current threat to humans appears low (see Preprint: A lethal human H5N5 influenza virus isolate exhibits low pandemic risk traits), there's still a lot we don't know about this emerging subtype.

All of which brings us to a new preprint which builds upon earlier reports, and finds evidence that H5N5 is more mobile than previously thought. They also report that it is more commonly detected in shore or seabirds, than in ducks and geese, as is common with H5N1.

The authors suggest that its carriage by seabirds and shorebirds necessitates `alternative surveillance strategies', and warns we may be missing cryptic transmission of the virus.

I've only posted some brief excerpts. Follow the link to read the preprint in its entirety. I'll have a postscript after the break

H5N5 virus transmission is driven by repeated cross-Atlantic introductions and transmission among high latitude seabirds

Clara R Malekshahi, Nicole St. Clair Knobloch, Alvin Crespo Bellido, Alexa Simulynas,  Stephanie Goya, Leigh Papalambros, William J. Fitzsimmons,  Alexander L. Greninger, Adam S. Lauring, Jonathan Runstadler, Martha I. Nelson, Wendy Puryear, Louise H. Moncla

doi: https://doi.org/10.64898/2026.10.29.762228
This article is a preprint and has not been certified by peer review 

Preview PDF

Abstract

In November 2025, the first global H5N5 infection was reported in a person in Washington State. Previously, these viruses had only been detected in seabirds and shorebirds near the Atlantic Ocean, suggesting potentially distinct ecology from dominant H5N1 strains.

Using 354 global H5N5 genomes, we show that H5N5 viruses have been carried by high latitude seabirds and shorebirds across the Atlantic at least 9 times, with introductions more frequent in the fall and spring. We reconstruct a plausible path of cross-continental movement via Arctic or sub-Arctic regions, followed by a year of cryptic circulation prior to human spillover.

These data show that H5N5 viruses have undergone far more intercontinental movements than previously recognized, and exhibit host and geographic patterns that are fundamentally distinct from dominant H5N1 lineages. The distinct host ecology, geography, and movement, paired with the capacity to infect a person, suggest that enhanced surveillance may be warranted.

       (SNIP)

Since its introduction into North America, surveillance and monitoring efforts for HPAI viruses are focused on H5N1 viruses in Anseriformes species. However, our data show that H5N5 viruses have been repeatedly introduced and have persistently co-circulated alongside predominant H5N1 strains, but with wholly distinct ecologies. 

These H5N5 viruses exhibit host distributions and geographic patterns of spread that are markedly different from those of H5N1, necessitating alternative surveillance strategies that are formulated to these lineages.

The close link between H5N5 transmission and seabird and shorebird ecology suggests that these viruses may continue to move across continents and circulate cryptically in these species, while the human infection shows that these viruses could pose spillover risk.

Increased surveillance in wild birds and mammals, as well as monitoring of key locations of repeated viral introductions, would be crucial for the prevention of further spread amongst wild birds and for the prevention of potential spillover into mammals.

        (Continue . . . )

Although this study is limited by small sample sizes, it does suggest that H5N5 may be better established in the environment than previously thought.  Given its persistence in high latitude birds, and repeated spillovers into mammals, it is definitely worthy of our continued attention.

Washington Adds 6 More H5N1 Infected Herds (n=40) - Indiana Reports 1st Infected Herd

 

#19,398

As the USDA dashboard indicates (above), 6 more dairy herds have been reported as being infected with H5N1 in Washington state, bringing to 40 the number identified since October 8th.  

All but one have been reported from Yakima County.

Although it is not yet reflected in the USDA dashboard, the USDA (h/t Maggie Fox on Twitter/X) has posted the following statement on Indiana's first detection of HPAI H5N1 B3.13 in a dairy herd. 

USDA Confirms Highly Pathogenic Avian Influenza in a Dairy Herd in Indiana

Contact: aphispress@usda.gov

Milk Supply Safe; Considered Low Risk to Human Health and Safety

WASHINGTON, D.C., November 2, 2026—Today, the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service (APHIS) National Veterinary Services Laboratories (NVSL) confirmed via PCR (polymerase chain reaction) detection of highly pathogenic avian influenza (HPAI) H5N1 genotype B3.13 in a dairy cattle herd in Indiana. This detection was a result of routine National Milk Testing Strategy testing, not pre-movement surveillance.

This marks the first reported case of HPAI in cattle in Indiana. While dairy cattle in a total of 21 states have been infected since the start of the outbreak in March 2024, APHIS has seen cases in previously unaffected states this year. APHIS is working closely with the Indiana State Board of Animal Health to conduct additional on-farm investigations, diagnostic testing, and epidemiological data collection to better understand the detection and prevent further disease spread.

The detection does not change USDA’s HPAI eradication strategy. Biosecurity is still key to mitigating the risk of disease introduction or spread between premises. APHIS recommends enhanced biosecurity measures for all dairy farms. Producers should immediately report any livestock with clinical signs, or any unusual sick or dead wildlife, to their state veterinarian.

This detection does not pose a risk to consumer health or affect the safety of the commercial milk supply. The U.S. Food and Drug Administration is confident that pasteurization is effective at inactivating HPAI virus, and that the commercial, pasteurized milk supply is safe. Dairies are required to send only milk from healthy animals into processing for human consumption; milk from impacted animals is being diverted from the commercial milk tank or destroyed so that it does not enter the human food supply.

According to the U.S. Centers for Disease Control and Prevention (CDC), HPAI viruses circulating in birds and U.S. dairy cattle pose a low risk to the general public in the United States. However, people who have job-related or recreational exposures to infected birds or mammals are at higher risk of infection and should take appropriate precautions outlined in CDC guidance

To recap:

• In addition to 40 infected herds in Washington  
• There have been 3 confirmed human infections in Washington state (1 fatal) 
• The first H5N1 infected herd reported by Colorado in nearly 2 years
• and now, this first spillover in Indiana.

All in the space of 3 weeks. 

 

South Korea: MAFRA Report on H5N1 In wild leopard cat in Seosan, South Chungcheong Province

Location of Seosan, South Korea

#19,397

While human infections get the bulk of our attention, the impact of HPAI H5 on avian and mammalian wildlife around the world is enormous and growing. 

• Devastating outbreaks in marine mammals (see here, here, and here) have killed tens of thousands of seals, sea lions, and dolphins. 

• Thousands of vultures, hawks, and falcons have succumbed to HPAI (see here, here, and here), including highly endangered California Condors. 

• Felines, both wild and captive, are highly susceptible to the virus, with the USDA's Detections of Highly Pathogenic Avian Influenza in Mammals dashboard lists more than 200 feline detections in the U.S. alone.

• Recent seroprevalence studies report a high incidence of infection among polar bears above the arctic circle (see Preprint: HPAI H5N5 in a Polar Bear and Atlantic Walrus, Svalbard, 2026, with Widespread Seroconversion in Polar Bears).

But most wildlife infections go unnoticed.  Marine mammals die at sea, or on remote beaches, and are never recorded.  When a massive die-off of birds occurs, no one counts the bodies.  When an infected fox dies in the woods, the evidence is quickly erased by scavengers. 

Australian citizens have reported over 70,000 suspected wildlife incidents over the past 5 months, yet only a tiny percentage have been investigated. 

As we discussed in early 2025 (see Nature Reviews: The Threat of Avian Influenza H5N1 Looms Over Global Biodiversity), no one really knows the full extent of  H5's carnage, or its likely impacts going forward. 

In the spring of 2025 South Korea reported their first mammalian wildlife infection with H5N1 in an endangered leopard cat. Today they report another wild leopard cat has succumbed to the virus. 

While this is only the second such detection, it is clear from this report they are taking it seriously, as is evidenced by their extensive guidance to the public. 

        (Translated . . .)

Highly pathogenic avian influenza (AI) detected in a wild leopard cat in Seosan, South Chungcheong Province… Surveillance and disease control measures strengthened

2026.11.02 15:30:08 Quarantine Policy Bureau Avian Influenza Prevention Division

The Ministry of Agriculture, Food and Rural Affairs ( Minister Song Mi-ryeong ) and the Ministry of Climate, Energy and Environment ( Minister Kim Sung-hwan ) announced on November 2 that the H5N1 highly pathogenic avian influenza (AI) virus was detected as a result of a detailed examination conducted by the National Wildlife Disease Control Center on the carcass of a wild mammal, a leopard cat * , found on October 23 near Ganwol Lake in Buseok-myeon, Seosan-si, Chungcheongnam-do, following a report by a local visitor .

* Class II Endangered Species, primarily feeds on rodents and birds ( home range approx . 10–20 km² )

This is the second time that highly pathogenic avian influenza (AI) virus has been detected in a wild mammal in Korea since it was first detected in a wild leopard cat in Hwasun, South Jeolla Province in March 2025 , and the first time this winter .

Meanwhile, the National Wildlife Disease Control Center, an agency under the Ministry of Climate, Energy and Environment, has been investigating whether wild mammals * secured through wildlife rescue centers , resident reports, and surveillance of major migratory bird habitats nationwide are infected with avian influenza (AI) .

Carnivorous and omnivorous mammals such as raccoons , weasels , badgers , wildcats , otters , martens , seals , and finless porpoises

※ Avian Influenza (AI) testing on 245 wild mammal samples from January to October 2026

The Ministry of Climate, Energy and Environment is implementing response measures in accordance with the Standard Operating Procedures (SOP) for Avian Influenza (AI) in wild mammals established following the case of infection in a wildcat in Hwasun-gun last year , and is strengthening cooperation with relevant agencies to reduce the risk of infection between wild animals , poultry , and humans .

As soon as highly pathogenic avian influenza (AI) was confirmed, the situation was shared with relevant agencies , including the Ministry of Agriculture, Food and Rural Affairs and the Korea Disease Control and Prevention Agency, and special surveillance was carried out in areas within a 10km radius of the detection site , including searching for dead wild mammals and conducting detailed on-site investigations , and emergency quarantine measures, such as on-site disinfection and access control, were requested from competent local governments, including Seosan City .

In addition , viral gene analysis is performed to identify the characteristics and origin of the infecting virus , and to investigate whether there is additional infection to surrounding wild animals and the possibility of transmission .

The Ministry of Agriculture, Food and Rural Affairs implemented emergency quarantine measures, such as surveillance and inspection , to prevent the spread to poultry farms within the quarantine zone ( 10km radius ) , and took measures to thoroughly clean and disinfect the interior and exterior of farms , facilities , and vehicles to preemptively block risk factors for the transmission of avian influenza .

Designation and operation of wild bird surveillance areas in accordance with the Avian Influenza Prevention and Control Guidelines

The Korea Disease Control and Prevention Agency ( Chungcheong Region Disease Response Center ) and local governments, including South Chungcheong Province, have stated that they are continuing to monitor the health status of field response personnel, including those who discovered the wildcat and rescue center staff, taking into account the virus's incubation period (10 days) to prevent human infection , and that there have been no suspected cases to date .

In addition , the Ministry of Climate, Energy and Environment provided the following information to the public to prevent the transmission and spread of highly pathogenic avian influenza (AI) .

First , you should refrain from visiting wildlife habitats, such as migratory bird sanctuaries, as much as possible . If you must visit, you should avoid contact with wild animals and be careful not to step on feces or bodily fluids . Furthermore , you should strictly observe personal hygiene rules, such as disinfecting shoes and vehicles and washing your hands after returning home, and avoid entering livestock farms .

In addition , even if you discover dead wild birds or mammals, or wild animals exhibiting abnormal behavior, do not touch or move them directly, but report them immediately to the competent local government so that the National Wildlife Disease Control Center can conduct avian influenza (AI) testing promptly .

※ Report to the relevant city , county , or district environmental department via the Government Civil Complaint Information Call Center (110 ) or the competent local government ( area code + 120 ) .

Livestock farm officials must strictly adhere to basic disease prevention guidelines, such as prohibiting entry to migratory bird habitats , controlling the entry of outside people and vehicles, and disinfecting the inside and outside of the farm daily. In addition , if suspected symptoms of highly pathogenic avian influenza (AI), such as the death of more poultry than usual, are confirmed , they must immediately report to the disease control authorities (1588-4060/9060) .

Lee Chae-eun, Director General of Nature Conservation at the Ministry of Climate, Energy and Environment, stated, “ As highly pathogenic avian influenza (AI) has been confirmed in wild mammals, specifically leopard catesses, again this year following last year, we will strengthen surveillance and inspections to closely investigate whether there are any additional infections in wild animals , and we will do our best to ensure the safety of field response personnel and the public . ” She added , “ We also ask the public to report any dead wild animals immediately without direct contact if they find them . ”

Lee Dong-sik , Director General of the Quarantine Policy Bureau at the Ministry of Agriculture, Food and Rural Affairs, stated, “ With highly pathogenic avian influenza (AI) confirmed in wild mammals ( leopard cats ) following wild birds, the risk of outbreaks has significantly increased as the related virus has entered poultry farms. ” He urged poultry farm officials to “ strictly adhere to basic quarantine rules , such as spraying rodenticides , ensuring the safe storage of carcasses, controlling the entry of outside people and vehicles, and disinfecting the inside and outside of the farm daily, to prevent wild animals from entering the farm . ”

A little over 3 years ago, in Avian Flu's New Normal: When the Extraordinary Becomes Ordinary, I wrote about the numbing effect that comes with the constant barrage of HPAI H5 reports from around the world.

Events that were nearly unthinkable four or five years ago (see Preprint: Mass mortality of southern elephant seals during multi-species outbreak of HPAI H5N1 on sub-Antarctic Heard Island) have now become `the new normal'.

While we may have become inured to these happenings, that doesn't make them any less impactful to our shared global ecosystem. What future challenges may arise from these continued viral insults to non-human species is difficult to predict.

But given our largely passive response to avian flu, we appear on track to find out.