|Credit Epidemiosurveillance Santé Animale|
While the HPAI H5 viruses currently spreading across Europe have not been linked to human infection, it isn't lost on the WHO and other public health agencies that flu viruses are constantly evolving, and their threat to human health can change over time.
The behavior of H5N8 this fall and winter - appearing with greater frequency and with much more virulence in wild and migratory birds than ever before - is just one example of how these viruses can change.We are also seeing new subtypes - like H5N5 - spin off from H5N8, and their threat to human health is uncertain. All of which as prompted the European Regional Office of the World Health Organization to release the following statement this morning:
WHO calls for heightened vigilance as avian influenza continues to spread in Europe
WHO is calling for heightened vigilance and strengthened surveillance efforts to prevent and detect potential human cases of avian influenza as it continues to spread in birds across Europe.
“No human cases of highly pathogenic avian influenza A(H5N8) have been reported so far in European countries, but this does not mean this cannot happen, as past experience tells us,” said Dr Caroline Brown, Programme Manager of Influenza and Other Respiratory Pathogens at WHO/Europe. “Countries reporting outbreaks in birds need to remain vigilant as avian influenza viruses can transmit from animals to humans.”
Europe’s outbreaks of influenza A(H5N8) virus in birds
Since June 2016, at least 24 countries in the WHO European Region have reported outbreaks of highly pathogenic avian influenza (HPAI) A(H5N8) virus in wild birds and domestic poultry. At least 3 of these countries have reported outbreaks in the last 2 weeks. Outbreaks have also been reported in countries in Africa, Asia and the Middle East.
This is the second time that this virus has caused outbreaks in Europe with the autumn migration of wild birds. The virus was first detected in birds in Asia in 2014, where it has continued to circulate. In June 2016 the virus was detected in waterbirds in the southern part of the Russian Federation, and by September 2016 the Food and Agriculture Organization of the United Nations had issued an alert for countries along the West Eurasian and Afro-Eurasian migration routes to watch for this virus.
Like other HPAI viruses, A(H5N8) can cause severe disease in birds, especially chickens. No human cases of avian influenza A(H5N8) have been reported to date. However, because similar influenza subtypes have caused human disease in the past, the possibility of transmission cannot be excluded.
Assessment of the risk of human transmission
The risk of transmission from birds to humans is relatively low. Although no human cases of HPAI A(H5N8) have ever been reported, it is important to remain vigilant.
Most human cases caused by other avian influenza viruses occurred after exposure through contact with infected poultry or contaminated environments, including live poultry markets. In areas with reported outbreaks of avian influenza in birds, people at potential risk are those in direct contact with/handling diseased birds and poultry, their carcasses and/or their environment.
Advice for the public in areas experiencing outbreaks in birds
- Avoid contact with any birds (poultry or wild birds) or other animals that are sick or found dead and report them to the relevant authorities.
- Do not touch birds or carcasses with bare hands. If you must handle a carcass, wear gloves or use an inverted plastic bag to collect the bird, and then wash your hands properly with soap or a suitable disinfectant.
- Follow good food safety and food hygiene practices in line with WHO’s 5 keys to safer food, such as cooking food thoroughly at sufficiently high temperatures.
Influenza A(H5N8) virus detected
Zoonotic influenza at the human–animal interface
Monthly global risk assessment for human illness from avian and swine influenza
Five keys to safer food manual (2006)