ECDC/EFSA Report: Drivers For a Pandemic Due to Avian Influenza

 
#17,986

While avian influenza remains primarily a threat to birds, it continues to evolve and adapt, and in recent years has increasingly spilled over into mammalian species, raising concerns that it could eventually adapt to humans. 

While the exact path the virus could take to pose a pandemic threat is unknowable, there are steps that we can take to reduce the risks.

We've looked at many of those previously, including:

• limiting or curtailing fur farms (see PNAS: Mink Farming Poses Risks for Future Viral Pandemics)
• the closure of live/bird animal markets 
• improving animal separation and biosecurity on `mixed species' farms.
• Use of PPEs, vaccines, and antivirals by farm workers (see Health Officer Urges People Living/Working On Poultry Farms To Get Seasonal Flu Vaccine)
• Keeping pets away from wild birds or other potential carriers of the virus (see CDC Updated Advice On Bird Flu in Pets and Other Animals).

Today the ECDC/EFSA has published a lengthy (24-page PDF) on the potential drivers of an avian flu pandemic, and steps that can be taken to reduce the threat to human health.  I've reproduced the news release, along with a link, abstract, and some excerpts from the report. 

Follow the link to read it in its entirety. 

Understanding avian influenza pandemic drivers crucial in reducing risks to human health
News
3 Apr 2024

In a joint report released today, the European Centre for Disease Prevention and Control (ECDC) and the European Food Safety Authority (EFSA) outline the contributing drivers for influenza A(H5N1) viruses to acquire the ability to spread efficiently among humans, thereby increasing their pandemic potential. The report also addresses which mitigation measures could be implemented in animals and humans to reduce the risk to human health.

The report examines intrinsic drivers related to virus characteristics or host susceptibility. It also discusses extrinsic drivers which may increase exposure of mammals and humans to avian influenza viruses, thereby stimulating mutation and adaptation to mammals. Such drivers include the ecology of host species such as wildlife, human activities like farming practices and use of natural resources, climatic and environmental factors.

Influenza viruses remain prevalent among wild bird populations in the EU/EEA, leading to significant illness and death in birds. Transmission between bird and mammal species has been observed, including in fur animal farms where outbreaks have been reported. Angeliki Melidou, ECDC Principal Expert on Respiratory Viruses, said:

“Transmission from infected birds to humans remains a rare event, with no confirmed human infection identified in the EU/EEA. Nonetheless, the potential for avian influenza viruses to adapt to humans and cause a pandemic remains a concern. Ongoing vigilance, preparedness efforts and an increased understanding of underlying drivers is therefore crucial”.

Key options for actions include enhancing surveillance targeting humans and animals, ensuring access to rapid diagnostics, promoting collaboration between animal and human sectors, and considering the implementation of preventive measures such as vaccination of poultry. Key options for actions include enhancing surveillance targeting humans and animals, ensuring access to rapid diagnostics, promoting collaboration between animal and human sectors, and considering the implementation of preventive measures.

Effective communication to different involved target audiences should be emphasised, as well as strengthening veterinary infrastructure, enforcing biosecurity measures at farms, and reducing wildlife contact with humans and domestic animals. Consideration of spacing between poultry and fur animal farming, especially in areas with high waterfowl density, could be given for effective risk reduction.

Drivers for a pandemic due to avian influenza and options forOne Health mitigation measures 

European Food Safety Authority (EFSA) | European Centre for Disease Prevention and Control (ECDC)

| Cornelia Adlhoch | Erik Alm | Theresa Enkirch | Favelle Lamb | Angeliki Melidou | Katriina Willgert | Stefano Marangon | Isabella Monne | Jan Arend Stegeman | Roxane Delacourt | Francesca Baldinelli | Alessandro Broglia 

Approved: 14 March 2024 DOI: 10.2903/j.efsa.2024.8735 

© 2024 European Food Safety Authority, European Centre for Disease Prevention and Control. EFSA Journal published by Wiley-VCH GmbH on behalf of European Food Safety Authority.

 Correspondence: biohaw@efsa.europa.eu 

Abstract 

Avian influenza viruses (AIV) remain prevalent among wild bird populations in the European Union and European Economic Area (EU/EEA), leading to significant illness in and death of birds. Transmission between bird and mammal species has been observed, particularly in fur animal farms, where outbreaks have been reported. While transmission from infected birds to humans is rare, there have been instances of exposure to these viruses since 2020 without any symptomatic infections reported in the EU/EEA.

However, these viruses continue to evolve globally, and with the migration of wild birds, new strains carrying potential mutations for mammalian adaptation could be selected. If avian A(H5N1) influenza viruses acquire the ability to spread efficiently among humans, large-scale transmission could occur due to the lack of immune defences against H5 viruses in humans. 

The emergence of AIV capable of infecting mammals, including humans, can be facilitated by various drivers. Some intrinsic drivers are related to virus characteristics or host susceptibility. Other drivers are extrinsic and may increase exposure of mammals and humans to AIV thereby stimulating mutation and adaptation to mammals. Extrinsic drivers include the ecology of host species, such as including wildlife, human activities like farming practices and the use of natural resources, climatic and environmental factors. 

One Health measures to mitigate the risk of AIV adapting to mammals and humans focus on limiting exposure and preventing spread. Key options for actions include enhancing surveillance targeting humans and animals, ensuring access to rapid diagnostics, promoting collaboration between animal and human sectors, and considering the implementation of preventive measures such as vaccination of poultry. Effective communication to different involved target audiences should be emphasised, as well as strengthening veterinary infrastructure, enforcing biosecurity measures at farms, and reducing wildlife contact with domestic animals. 

Careful planning of poultry and fur animal farming, especially in areas with high waterfowl density, is highlighted for effective risk reduction. 

KEYWORDS highly pathogenic avian influenza, humans, mammals, pandemics, poultry, zoonotic virus

(SNIP)

Options for One Health risk mitigation measures: 

The risk mitigation measures for the emergence of AIV adapted to mammals and humans should aim at limiting the exposure of mammals, including humans, to AIV and preventing its spread. The main measures are listed below. 

• Surveillance targeting humans and animals should be enhanced, together with genomic analysis and the sharing of sequence data. Animals targeted should include wild birds, poultry, captive birds and the most susceptible domestic mammals (e.g. fur animal farms, mixed farms of poultry and fur animals or poultry and pigs, and cats) as well as susceptible wild mammals, especially peri-urban and peri-domestic mammals. 

• Access to rapid, sustainable and cost-effective diagnostic processes, including genomics, for AIV screening of relevant animal (both domestic and wild) populations is imperative, and need to be maintained in resource-limited settings as well. 

• Strong collaboration between animal and human sectors and the involvement of authorities for occupational safety and health (in settings where workers are involved) is paramount. Other preventive measures should focus on minimising exposure, ensuring correct use of appropriate personal protective equipment and hygiene measures, reducing environmental contamination and enhancing biosafety and biosecurity measures, as necessary. 

• Individuals who are occupationally exposed to animals infected with AI can be offered vaccination against seasonal influenza and/or influenza A(H5) virus for protection and to minimise the risk of reassortment between avian and human seasonal influenza strains. Specific vaccination recommendations are under the remit of national authorities. Antivirals can be used to treat infected persons or as post-exposure prophylaxis when there are contacts of human cases. 

• Vaccination of animals is an additional prevention strategy of AI infection at farms, complementary to stamping-out policies applied to control the infection. Vaccination should be coupled with surveillance to monitor the evolution of the field virus and identify any possible antigenic changes, including possible vaccine-induced mutations. 

• It is important for public health authorities to communicate to the public about the possibility of human infection by AI. Awareness-raising programmes should target multiple audiences under a co-ordinated One Health prevention and control plan. Main target groups include the agricultural community in collaboration with occupational safety authorities, stakeholders connected to wildlife (e.g. hunters, researchers and managers), pet keepers and the general public. 

• Preparedness and capacity of the veterinary infrastructure and of other relevant competent authorities including those responsible for wildlife in at-risk and affected countries should be increased, to mitigate the risk of a large spread of HPAI viruses in domestic and wild animals. 

• Biosecurity should always be in place at farms to limit exposure of domestic animals to infection and its spread, including preventing direct or indirect contact of farmed animals with wild birds and other wildlife, contaminated fomites or feed (e.g. dead wild birds or raw poultry meat), and avoiding farming multiple susceptible species at the same high-risk location. 

• Actions should be taken to reduce the contact and risk of transmission between (synanthropic) wildlife and poultry or other domestic animals. This can be achieved by making sure wildlife and companion animals are kept out of farm facilities that there is, proper waste and wildlife carcass removal and, if possible, limiting outdoor access for companion animals in risk areas. 

• Careful planning and reorganisation of poultry and fur animal farming is essential, particularly regarding the location and density of poultry farms, especially those in high-risk areas close to wetlands with a high density of waterfowl. Additionally, farming highly susceptible species at this should be kept outdoors at high density