In July 2023 the WHO, Food and Agriculture Organisation (FAO), and the World Organisation for Animal Health (WOAH) united in a statement urging countries to collaborate across sectors to save animals and protect people from avian influenza. Current global outbreaks are causing “devastation” in animal populations, including some mammals. Although these are largely affecting animals, they pose “ongoing risks to humans”.  

From birds, to mammals, to humans 

Avian influenza viruses are most commonly spread among bird populations, but an increasing number of H5N1 avian influenza cases are being found in mammals. This is of particular concern because of the biological proximity to humans, creating an environment in which the virus could adapt to infect humans. Furthermore, some mammals can act as “mixing vessels”, leading to the emergence of more harmful viruses.  

In 2022, 67 countries across 5 continents reported H5N1 outbreaks in poultry and wild birds to WOAH. A resultant 131 million or more domestic poultry were lost due to death or culling in affected communities. In 2023, a further 14 countries have reported outbreaks, with several mass death events reported in wild birds.  

Since 2022 10 countries across 3 continents have reported outbreaks in mammals to WOAH, with both land and sea mammals infected. These have ranged from farmed mink to domestic dogs, and sea lions to seals. At least 26 species are known to have been affected.  

Dr Gregorio Torres, Head of the Science Department at WOAH, identifies a concerning change in the virus. 

“There is a recent paradigm change in the ecology and epidemiology of avian influenza, which has heightened global concern as the disease spread to new geographical regions and caused unusual wild bird die-offs, and alarming rise in mammalian cases.”  
What is the risk? 

Although infections in humans have also been reported, they remain “very rare”; only 8 cases have been identified since the end of 2021. However, they can cause “severe disease” with a “high mortality rate”. So far, cases are linked to close contact with infected birds or contaminated environments.  

Dr Sylvie Briand, Director of Epidemic and Pandemic Preparedness and Prevention at WHO does not believe the virus is able to transmit between humans “easily”. However, she calls for “vigilance” to identify “any evolution in the virus that can change that”. With FAO and WOAH, WHO is monitoring the evolution of the viruses, looking for “signals of any change”. 

“We encourage all countries to increase their ability to monitor these viruses and to detect any human cases. This is especially important as the virus is now affecting countries with limited prior experience in avian flu surveillance.”  

Dr Keith Sumption, Chief Veterinary Officer at FAO, identifies rapid evolution in the epidemiology of H5N1.  

“FAO brings attention to the need for vigilance and timely sharing of genetic sequences to monitor the molecular epidemiology for risk assessment and better disease control.”  
How can we stop the spread? 

FAO, WHO, and WOAH encouraged countries to take the following actions: 

  • Prevent avian influenza at the source through enhanced biosecurity measures and good hygiene practices. Poultry vaccination may also be considered as a complementary disease control tool. 
  • Rapidly detect, report, and respond to animal outbreaks, implementing the control strategies set out in WOAH standards.  
  • Strengthen influenza surveillance in animals and humans.
    • In animals, risk-based surveillance should be enhanced before and during high-risk periods. Cases should be reported in a timely manner and genetic sequencing should be periodically conducted.  
    • In humans, surveillance, careful review of unusual epidemiological patterns, reporting of infections and sharing of viruses with GISRS should be prioritised. 
  • Conduct epidemiological and virological investigations around animal outbreaks and human infections. 
  • Share genetic sequence data in publicly accessible databases, even before publication. 
  • Encourage collaboration between sectors, especially in areas of information sharing, joint risk assessment, and response. 
  • Communicate the risk. Healthcare workers and occupationally exposed people should be alerted and trained, and the public should be encouraged to avoid contact with sick or dead animals.  
  • Ensure influenza pandemic preparedness at all levels. 

The three organisations have been convening experts to review the situation, monitor the virus’ evolution, and update recommendations. Furthermore, they will work with countries in preparedness and response and facilitate collaboration across countries and sectors.  

What measures are you taking to prevent infections in your area, or have you encountered avian influenza already? For a specific panel on how vaccines and vaccination strategies can tackle avian influenza outbreaks at the World Vaccine Congress in Barcelona this October, get your tickets here. Don’t forget to subscribe for more updates like this!