The first human case of H9N2 influenza virus (bird flu) has been reported in Europe. A human infection was recorded by the Italian Ministry of Health on March 25, 2026.
Author
- Ed Hutchinson
Professor, MRC-University of Glasgow Centre for Virus Research, University of Glasgow
As an influenza virologist, I can explain what this means and why I am not particularly worried by it - yet.
What do we know about this case?
The patient was infected outside of Europe before travelling to the Lombardy region of northern Italy. Lombardy's welfare councillor Guido Bertolaso has reported that the patient is a boy with underlying health conditions who was diagnosed after returning from a visit to Africa.
Fortunately, his infection hasn't made him seriously unwell, but he has been placed in hospital isolation in the San Gerardo hospital in Monza. Italian public health authorities diagnosed H9N2 influenza virus infection using laboratory tests that detect the virus's genetic material.
What is H9N2 influenza virus?
H9N2 influenza viruses are influenza A viruses. This large group of viruses includes two of the viruses causing human seasonal influenza (H1N1 and H3N2) as well as many other viruses that infect birds.
H9N2 influenza viruses are classified as "low pathogenicity avian influenza viruses". "Low pathogenicity" refers to their ability to cause disease in poultry (avian influenza is a major threat to poultry farming), but it is unusual for H9N2 to cause anything other than mild illness in humans.
H9N2 is not well suited to infecting humans, and when it does manage to do so it tends to be through direct contact with poultry in heavily contaminated environments . Although this was the first human case in Europe, hundreds of human H9N2 cases have been recorded previously, mainly in China, but also in other countries across Asia and Africa .
What is the level of risk to humans?
Hopefully, the infected patient will make a good recovery. At the moment, the wider risk to humans is very low .
Why is this? Virologists look for multiple factors when assessing if an isolated human infection with an animal virus is likely to cause wider problems - in the worst case a pandemic, which avian influenza viruses have caused repeatedly in the past. This case of H9N2 currently shows no signs of this.
We know that this particular strain of influenza virus would need to acquire mutations in order to become well adapted to growing in humans . As a precaution, Italian public health authorities have traced contacts of the patient to confirm there was no onwards transmission. At the moment, it seems very unlikely that this will go any further.
However, there is a wider picture. There are many influenza viruses out there that are much more unpleasant than H9N2. Most troubling is the ongoing worldwide outbreak of H5N1 avian influenza viruses, which are much more pathogenic and are showing a troubling tendency to infect mammals .
An isolated case of H9N2 influenza in Europe may not be a major problem itself, but it is a reminder that we need to remain vigilant in monitoring the unpredictable behaviour of avian influenza viruses.
Ed Hutchinson receives funding from UKRI and the Wellcome Trust. He is the Chair of the Microbiology Society's Virus Division, a Board Member of the European Scientific Working Group on Influenza, an unpaid scientific advisor to Pinpoint Medical, and has sat on an advisory board for Seqirus.
