UK APHA: Detection of Avian H7N1 In Grey Seal

 
Credit UK APHA

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We've known for decades that marine mammals (seals, whales, sea lions, otters, etc.) are susceptible avian, and other types, of influenza viruses. The emergence and spread of HPAI H5Nx clade 2.3.4.4b around the globe has killed tens - perhaps hundreds - of thousands of pinnipeds over the past 2 years.

Preprint: Pathology of Influenza A (H5N1) Infection in Pinnipeds Reveals Novel Tissue Tropism and Vertical Transmission.

Nature Reviews: The Threat of Avian Influenza H5N1 Looms Over Global Biodiversity

But other avian viruses have been documented in marine mammals for decades. A few (of many) reports include: 

• During the winter of 1979-1980 seals were found suffering from pneumonia on the Cape Cod. In that instance, the culprit turned out to be an H7N7 influenza. (see Isolation of an influenza A virus from seals G. Lang, A. Gagnon and J. R. Geraci)
• In November of 2011 a die off of seals in New England that was eventually tied to an H3N8 avian Flu Virus. 2012's mBio: A Mammalian Adapted H3N8 In Seals, presented  evidence that this virus had recently adapted to better bind to alpha 2,6 receptor cells, the type found in the human upper respiratory tract. 

• A large outbreak was reported from northern Europe (mostly Denmark and Germany & Sweden) in 2014, when as many as 3,000 harbor seals reportedly died from avian H10N7 (see Avian H10N7 Linked To Dead European Seals), prompting warnings to the public not to touch seals.
• In 2017, during the HPAI H5N8 epizootic in Europe, that emerging subtype (clade 2.3.4.4.B) was found in Grey seals in the Baltic Sea (see EID Journal: Highly Pathogenic Avian Influenza A(H5N8) Virus in Gray Seals, Baltic Sea). 

Earlier this year the UK reported (two) outbreaks of clade 2.3.4.4b HPAI H5N5 in Grey seals (see here, and here). They reported finding the mammalian adaptive mutation PB2-E627K mutation in some of these isolates.

This amino acid substitution has been seen in other mammalian spillovers (see Cell Reports: Multiple Transatlantic Incursions of HPAI clade 2.3.4.4b A(H5N5) Virus into North America and Spillover to Mammals).

This week the UK's APHA/Defra is reporting the detection of a low-path avian H7N1 virus in a grey seal pup, which was found dead near Cornwall.  While H7 viruses have been (rarely) reported in pinnipeds, this (AFAIK) appears to be the first confirmed H7N1 virus. 

First the brief report, after which I'll have a bit more on H7 viruses. 

Note 2: findings in a grey seal in Cornwall

Sampling of a dead 8-month-old grey seal reported in Cornwall confirmed the presence of influenza A of subtype H7N1. The potential source of infection is wild birds, although very few seal sequences are available and the diversity of influenza A viruses in seals is poorly understood as is the dynamic of virus exchange between seals and birds. The cleavage site sequence indicated a motif consistent with a low pathogenicity virus if this virus had been found in poultry. However, the relevance of that cleavage site for seals is less clear.

The sequence generated from this positive seal sample included a mammalian adaptive mutation (E627K) in one gene (PB2) but this mutation has been observed in numerous positive samples from mammals detected previously both in Great Britain and globally, and in isolation isn’t considered to represent an increase in zoonotic risk. We cannot determine with certainty whether influenza A was the sole cause of death, and it is possible other factors may have contributed.

While H5 avian viruses have captured most of our attention over the past 25 years, for 5 years during the last decade China's H7N9 epidemic showed us that H7 viruses has genuine pandemic potential, producing > 1600 infections in China.

H7N9 Epidemic Waves - June 14th 2017 - Credit FAO

Other human spillovers include:

• In December of 2016, at least two veterinarians caring for sick cats at a NYC shelter were mildly infected with H7N2 (see J Infect Dis: Serological Evidence Of H7N2 Infection Among Animal Shelter Workers, NYC 2016).

• 3 mild cases were reported in Italy in 2013 (see ECDC Update & Assessment: Human Infection By Avian H7N7 In Italy).

• Mexico reported a couple of mild human H7N3 infections back in 2012 (see MMWR: Mild H7N3 Infections In Two Poultry Workers - Jalisco, Mexico), resulting in conjunctivitis without fever or respiratory symptoms.

• Twenty-two years ago (2003) world's attentions were focused on a different avian flu virus - HPAI H7N7 - which spread rapidly across hundreds of poultry farms in the Netherlands, infecting scores of farmers, and which killed a local veterinarian (see Human-to-human transmission of avian influenza A/H7N7, The Netherlands, 2003).

A follow up investigation of the 2003 outbreak by the RIVM found the spread of the virus to be far greater than originally reported, suggesting as many as 1,000 human infections occurred. 

So, while H7 viruses are generally thought of as being less dangerous than H5 viruses - and primarily an agricultural concern - that reputation is not entirely warranted.

That said, the detection of H7N1 in a single seal pup in the UK is mostly likely a one-off, or incidental finding. Obviously, if more turn up, it will warrant additional scrutiny. 

But this is another reminder that much of what happens with viral evolution goes on outside of our view.  While we focus on our current  HPAI H5 threat, we could easily be blindsided by something brewing unseen out in left field. 

Which is why we need to treat pandemic preparedness as integral to our national security, not as something we hastily ramp up whenever a new threat appears. 

eBioMedicine: Susceptibility and Shedding in Mx1+ and Mx1− Female Mice Experimentally Infected with Dairy Cattle A(H5N1) Influenza Viruses

 

Balb/cj Mice - Credit Wikipedia

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In June of last year we saw - for the very first time - mice (Mus musculus aka the common house mouse) added to the USDA's list of wild mammals detected with H5N1 in the United States (see USDA Adds House Mouse To Mammals Affected by H5N1).

This was somewhat unexpected, as wild mice naturally express Mx1 - a resistance factor that significantly reduces (but doesn't entirely eliminate) their susceptibility to influenza A viruses  - which is why genetically altered Mx1- (deficient) mice are often used in influenza research.

Since then, more than 1/3rd of all H5 infected wildlife reported to the USDA (132 out of 384) have come from mice (n=124) or rats (n=8), many of which were recovered in or near infected dairy farms.  

Last September we looked at two studies which challenged previously held assumptions (see 2007's Mx1 gene protects mice against the highly lethal human H5N1 influenza virus): 

• First, in Emer. Microbe & Inf.: HPAI Virus H5N1 clade 2.3.4.4b in Wild Rats in Egypt during 2023, we a surprisingly high percentage of wild rats testing positive for H5 antibodies in Egypt.

• A second, a study in Pathogens (Susceptibility of Synanthropic Rodents to H5N1 Subtype HPAI Viruses), where researchers challenged several rodent species (house mice, brown rat, black rat) with two (older 2010, 2007) HPAI H5N1 viruses, and found they are both susceptible to the virus and could potentially play a role it its evolution and spread.

Evidence now suggests the susceptibility of Mx1+ mice to H5N1 varies depending upon the strain - and as the HPAI virus continues to adapt and evolve -  older research must be revisited. 

Today we've a new study, specifically focused on the susceptibility and shedding of Bovine (genotype B3.13) H5N1 in both Mx1+ and Mx1- laboratory mice, that finds both are susceptible to the virus, and both excrete the virus in their urine.  

It is worth noting that exposure to mouse/rat urine and/or dropping is often associated with transmission of many zoonoses, including hantaviruses, leptospirosis, Tularemia, and Lassa fever (see Viruses Review - The Hidden Threat: Rodent Borne Diseases).

While many will want to read the full open access report, I've posted the link and some excerpts below.  I'll have a bit more after the break.

Susceptibility and shedding in Mx1+ and Mx1− female mice experimentally infected with dairy cattle A(H5N1) influenza viruses

Asim Biswasa,f ∙ Amie J. Eisfelda,f ∙ Lizheng Guana ∙ Chunyang Gua ∙ Tong Wanga ∙ Hassanein H. Abozeida,e ∙ et al. Show more

Summary

Background

Clade 2.3.4.4b highly pathogenic avian influenza A(H5N1) (HPAI H5N1) viruses have spread prolifically in dairy cattle in the US, resulting in dozens of human infections, some without well-established links to animal contacts. Many wild mammals have also been affected, including peridomestic house mice.

Methods

Here, we evaluated susceptibility, tissue tropism, and shedding in female PWK/PhJ and BALB/cJ mice, two laboratory strains derived from house mice that differ in expression of the antiviral restriction factor Mx1. PWK/PhJ mice, which were selected for their natural expression of Mx1, better reflect the antiviral capacity of most wild house mice, whereas BALB/cJ mice lack functional Mx1.

Findings

We found that, regardless of Mx1 expression status, mice are susceptible to infection by dairy cattle HPAI H5N1 viruses, that infection leads to systemic spread to non-respiratory sites, and that infected animals shed virus into the environment via urine. Shed virus remained infectious in urine for at least 24 h at room temperature.

Interpretation

These findings suggest that wild house mice could contribute to HPAI H5N1 environmental contamination and may play a role in transmission to other hosts.

Funding

This work was supported by the National Institute of Allergy and Infectious Diseases Centers of Excellence for Influenza Research and Response (contract 75N93021C00014) and by grants from the Japan Agency for Medical Research and Development (JP25wm0125002, JP253fa627001, and JP24fk0108626, to Y.K.).

Research in context

Evidence before this study

The recent outbreak of highly pathogenic avian influenza A(H5N1) (HPAI H5N1) viruses in dairy cattle has led to multiple human infections and the first reported HPAI H5N1-related death in the United States, according to the CDC. Surveillance data reported by the USDA has also identified infections in several wild mammal species, including wild house mice, which frequently live near humans and livestock. Previous studies have shown that laboratory mice lacking the influenza restriction gene Mx1 are susceptible to infection with HPAI H5N1 from dairy cattle. However, it remains unclear whether mice with a functional Mx1 gene—such as those found in wild populations—can support viral replication and shed virus in ways that might contribute to transmission risk.

Added value of this study

We demonstrate that mice naturally expressing a functional Mx1 gene are susceptible to infection with dairy cattle-derived HPAI H5N1. The virus disseminated systemically, was shed in urine, and remained infectious in urine for at least 24 h at room temperature. These findings suggest that wild mice may contribute to environmental contamination and could potentially play a role in interspecies transmission.

Implications of all the available evidence

Although the role of rodents in the spread of HPAI H5N1 is not yet fully understood, our findings provide experimental evidence that wild-derived mice expressing Mx1 can become infected, develop severe disease, and shed infectious virus. These results support the need for further investigation into the contribution of wild rodents to HPAI H5N1 transmission on farms and suggest that rodent control may be an important component of biosecurity strategies.

        (Continue . . . )

 

Surveillance for HPAI in wildlife in the United States - and the rest of the world - is mostly passive, and relies both on a combination of luck and a willingness of local authorities to report and/or test dead animals. 

The USDA map of HPAI H5 detections since early 2022 (below) suggests that some states may be looking harder than others.  Indeed, some states have yet to report a single finding. 

Admittedly, many animals die unseen in remote swamps, forests, or deserts while others may recover, escaping detection (see Emerg. Microb. & Inf.: High Number of HPAI H5 Virus Infections & Antibodies in Wild Carnivores in the Netherlands , 2020–2022). 

Even the most aggressive jurisdictions are apt to miss the vast majority of infections in the wild. We are undoubtedly only seeing the tip of the iceberg. 

We have seen a few studies where researchers have proactively sampled rodents, shrews, and voles in the wild for novel, or zoonotic, viruses. 

• In 2015's Taking HPAI To The Bank (Vole) found this European mammal was susceptible to two types of avian flu viruses (H5N1 & H7N1), most were able to carry the virus asymptomatically, shed the virus in copious amounts, and were able to pass on the virus to naïve co-housed sentinel voles.

• A 2019 study out of Boston found RT-PCR evidence of IAV (Influenza A Virus) in 11% of 163 Norway rats (Rattus norvegicus) trapped and swabbed (note: half came from paw swabs, which may indicate contamination rather than infection). 

• And just last year, in Nature: Decoding the RNA Viromes in Shrew Lungs Along the Eastern Coast of China - we looked at a study that found a wide range of zoonotic viruses - including HPAI H5N6 - in shrews.

Sadly, nearly 4 years into this North American HPAI epizootic we know surprisingly little about the ecology of H5Nx in mammalian wildlife, and whether they are capable of spreading these viruses to livestock, pets, and even humans. 

The unseen impacts of long chains of infection over time; in cattle, poultry, wild birds, and in peridomestic animals (mice, rats, cats, voles, skunks, etc.) should give us pause.

 

While most will end up evolutionary failures - like in the classic serial passage experiment shown above - something new and improved may emerge over time. 

And if we aren't actively looking, we'll never see it coming. 

EU Commission: EU Stockpiling and Medical Countermeasures Strategies to Strengthen Crisis Readiness and Health Security

 

Medical Countermeasures 

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Yesterday the European Commission - which presides over 27 countries and nearly 450 million people - announced two major initiatives for dealing with a wide variety of manmade and natural disasters;  an EU stockpiling strategy and a medical countermeasures strategy. 

This comes just over 3 months after the EU made headlines after calling for all households to prepare for a wide array of disasters (see excerpts below).

What type of crises is the EU preparing for? 

The EU is preparing for a broad spectrum of risks and threats, encompassing both natural and human-induced disasters. This includes:

• Natural disasters: floods, wildfires, earthquakes, and extreme weather events exacerbated by climate change.
• Human-induced disasters: industrial accidents, technological failures, and pandemics.
• Hybrid threats: cyberattacks, disinformation campaigns and foreign information manipulation and interference (FIMI), and sabotage of critical infrastructure.
• Geopolitical crises: armed conflicts, including the possibility of armed aggression against Member States.

       (SNIP)

In which areas will the EU focus its efforts to enhance population preparedness?

The EU will focus its efforts on enhancing population preparedness working with Member States, with a particular emphasis on fostering a culture of resilience at national and local level. This includes improving public awareness of risks through targeted information campaigns, educational programs, and accessible online resources.

Efforts will also concentrate on empowering citizens to take proactive measures to prepare for crises, such as developing household emergency plans and stockpiling essential supplies. The EU will also support the development of effective public warning and crisis communication systems by Member States to reach all citizens, regardless of their location, language, or circumstances.

Many of the EU's recommendations for household preparedness mirror longstanding advice by FEMA for Americans, but despite seeing dozens of regional disasters each year, many Americans remain underprepared. 

 

Although some (mostly Nordic) European countries have long recommended citizens have a 72-hour stockpile of emergency essentials in the home, for most of Europe this represents a major shift in both tone and policy. 

While some of this is obviously motivated by the ongoing conflict in the Ukraine (and the resultant increasingly bellicose rhetoric between the East and West), the harsh impact of COVID, increasingly frequent natural disasters, and the rising threat of cyberattacks and terrorism are all factors. 

The press release follows (which includes links to individual documents).  I'll have a bit more after the break.

EU Stockpiling and Medical Countermeasures Strategies to strengthen crisis readiness and health security

The European Commission launches today two initiatives under its Preparedness Union agenda: an EU Stockpiling Strategy and a Medical Countermeasures Strategy. Both are designed to improve access to essential goods for European citizens and societies, businesses and economies – ensuring continuity of essential goods and lifesaving medical supplies at all times, in particular during crises such as major energy blackouts, natural disasters, conflicts or pandemics.

EU Stockpiling Strategy: safeguarding essential supplies ahead of crises

The EU Stockpiling Strategy is designed to secure essential goods — such as food, water, oil, fuel and medicines – in the event of a crisis. It is the first ever EU comprehensive approach to stockpiling.

Key actions in the Stockpiling Strategy include:

• Establishing an EU Stockpiling Network with Member States to share best practices, coordinate stocks, and develop joint recommendations.
• Identifying stock gaps and duplications through information sharing and strengthening cooperation among Member States and with the EU.
• Expanding EU-level stockpiles to fill gaps in essential goods, supported by initiatives like rescEU for medical gear, shelter, generators, and more.
• Enhancing transport and logistics for rapid crisis response.
• Promoting civil-military, public-private, and international partnerships to maximise resource use efficiently and on time.

Medical Countermeasures Strategy: fortifying health crisis preparedness

With rising disease outbreaks and growing antimicrobial resistance, exacerbated by climate change, deteriorating biodiversity and ecosystems, and geopolitical challenges, the EU's Medical Countermeasures Strategy seeks to accelerate the development, production, deployment, and accessibility of lifesaving medical tools. 

Key actions of the strategy include:

• Advancing next-generation flu vaccines, new antibiotics for antimicrobial resistance, antivirals for vector-borne diseases, and improving access to CBRN countermeasures.
• Boosting intelligence and surveillance by developing an EU list of priority medical countermeasures, preparedness roadmaps, and EU/global wastewater sentinel systems.
• Accelerating innovation via the Medical Countermeasures Accelerator, R&D hubs, and expanding the HERA Invest programme.
• Securing scalable production through EU FAB's ever-warm capacity and the new RAMP UP partnership.
• Improving medicine access and deployment through joint procurement and support for ready-to-use labs.
• Strengthening global cooperation and cross-sector collaboration, including civil-military preparedness, public-private efforts, citizen readiness, and workforce investment.

Together, these strategies mark a key step toward a more proactive European response in the face of future crises.

Background

The EU Stockpiling Strategy and the Medical Countermeasures Strategy are two of the key actions announced in the Preparedness Union Strategy that was adopted in March 2025. Building on the Niinistö report recommendations, the EU-wide Stockpiling Strategy will integrate all existing sectorial stockpiling efforts, strengthen access to critical resources across the EU and combine centralised EU-level reserves with Member States' contributions, supported by public-private partnerships to ensure efficiency, scalability and cost-effectiveness.

The report also highlighted the urgent need to reinforce the EU's preparedness for all-hazard threats. In this regard, the Medical Countermeasures Strategy aims to boost coordinated action both within the EU and at global level to accelerate the development, production, and rapid deployment and access to lifesaving medical tools, including vaccines, therapeutics, diagnostics, and protective equipment. This will reinforce our collective resilience and ability to prepare and respond to health emergencies.

For more information

Communication on Medical Countermeasures Strategy

Communication on Stockpiling Strategy

Question and answers on Medical Countermeasures Strategy

Question and answers on Stockpiling

Factsheet on Stockpiling

Factsheet on Medical Countermeasures

HERA Website

DG ECHO

This is a comprehensive and ambitious plan, and will realistically require many years to fully implement. But given the state of the world today, increasing household, national, and regional preparedness against `all threats' makes a lot of sense.  

The reality is - in a major disaster - a government's response may be limited, and you and your loved ones may be on your own for the first few days. 

Living as I do in Hurricane country - and being the veteran of multiple storms and  evacuation orders (see here, here, here) - I try to maintain a high level of personal preparedness. 

My `standard advice' is that everyone should strive to have the ability to withstand 7 to 10 days without power and water. Recommended preps include:

• 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

Being prepared doesn't guarantee you and your loved ones will come through a major disaster unscathed. But it is relatively cheap insurance, and when things do go sideways, it can substantially improve your chances.

For more on personal and household preparedness, you may wish to revisit:

Emergency Preparedness: A Medicine For The Melancholy

The Gift of Preparedness 2024

Instead of Cursing The Darkness