Avian Influenza's Alarming Spread: Are We Prepared for the Next Pandemic?
While Australia has largely escaped the devastating outbreaks of highly pathogenic avian influenza A (HPAI) that have ravaged other regions, a silent threat is emerging. Recent reports reveal a disturbing trend: avian influenza viruses are jumping species barriers, infecting not only birds but also mammals like cats and dairy cattle. But here's where it gets truly concerning: human cases of avian H5N1 influenza are on the rise, with documented instances in the United States, Cambodia, and even Australia itself.
Imagine this: in the United States, 70 cases of the H5N1 clade 2.3.4.4b virus have been reported in recent years, while Cambodia saw at least 83 cases between 2003 and 2025, including eleven in 2025 alone. Most of these cases were linked to contact with infected animals or contaminated environments. While many recent US cases have been mild, severe illness and even deaths have occurred, highlighting the virus's potential for harm.
And this is the part most people miss: serosurveys suggest avian influenza infections in humans might be more common than we think. In Michigan and Colorado, 7% of dairy workers tested positive for H5N1 antibodies, indicating past exposure. This raises alarming questions about the virus's ability to mutate and potentially become more transmissible between humans, or to recombine with other circulating influenza strains, creating even more dangerous variants.
Australia's first human case of H5N1, reported in May 2024, was a traveler infected with an Indian strain. This was swiftly followed by outbreaks of HPAI H7N3 and H7N8 in poultry farms across Victoria and New South Wales. While these outbreaks were successfully contained through decontamination, they served as a stark reminder of the virus's proximity. New Zealand also reported its first HPAI H7N6 cases in poultry in 2024, while China saw human infections with H9N2 and a novel triple reassortant H3N3 virus. Even Antarctica hasn't been spared, with H5N1 detected in various animal species.
Can our labs detect the threat? While animal health authorities monitor avian influenza in animals, the ability of human pathology laboratories to detect these viruses is less clear. Many diagnostic tests approved for human influenza lack information on their ability to identify specific avian strains, particularly the highly divergent H7 and H9 subtypes. This knowledge gap is crucial, as early detection is key to preventing outbreaks and minimizing public panic.
Our study, conducted in July 2024, assessed the ability of twelve diagnostic assays used by NSW Health Pathology laboratories to detect the H7N8 virus responsible for the recent outbreak. We also analyzed data from the Royal College of Pathologists of Australasia Quality Assurance Programs (RCPAQAP) Emerging Biological Threats survey, evaluating the detection of five other avian influenza viruses: H5N1, H7N3, H7N9, H9N2, and H10N7.
The results were reassuring: all twelve assays detected the H7N8 virus, and the RCPAQAP survey confirmed 100% detection rates for all six avian influenza A viruses tested. This suggests that current human diagnostic tests are highly effective at identifying these strains, even the highly pathogenic ones involved in recent outbreaks.
But the story doesn't end here. Our findings raise important questions: How prepared are we for new, potentially more dangerous avian influenza strains? Access to outbreak viruses and international collaboration are crucial for developing and testing accurate diagnostics. Early detection is vital, especially for viruses that have evolved in animal hosts. Furthermore, identifying avian influenza as influenza A is essential before subtyping, allowing for targeted public health responses and informed decision-making regarding workforce management and resource allocation.
Our study highlights the importance of collaboration between human and animal health authorities. By working together, we can strengthen our ability to detect and respond to emerging zoonotic threats like avian influenza, protecting both human and animal health.
What do you think? Are we doing enough to prepare for the next potential pandemic? Share your thoughts in the comments below.
