Australia hit by bird flu outbreak of highly pathogenic strain

With eggs in short supply and avian influenza spreading across Australian farms, the outbreak has the country on edge.

Since May, several poultry farms in the states of Victoria, New South Wales and the Australian Capital Territory have been hit with avian influenza, or bird flu.

These outbreaks have been devastating for the affected poultry farms, leading to large-scale culls, and caused knock-on effects for the country's egg supplies.

"The bird flu situation in Australia is increasingly alarming, particularly due to the threat posed by the highly pathogenic avian influenza (HPAI) H5N1 strain, which has not yet reached the continent," said associate professor Dr Vinod Balasubramaniam, a molecular virologist with the Jeffrey Cheah School of Medicine and Health Sciences at Monash University's campus in Malaysia.

Professor Adrian Esterman, head of Biostatistics and Epidemiology with the University of South Australia, said the current worldwide H5N1 outbreak has affected a wider range of bird species than previous outbreaks and has led to significant losses in both wild bird populations and poultry flocks worldwide.

"The disease has also spread to a wide range of wild and domestic animals, including several cow herds in the US," he told China Daily.

"At the moment, it is people working with poultry or infected animals or hunters that have caught the disease, and there is no evidence to date of person-to-person transmission.

"The risk of widespread transmission of H5N1 among mammals and potential spillover to humans remains a concern, although at the moment the risk to humans is considered low," he said.

Balasubramaniam agreed, telling the China Daily the H5N1 strain "poses a significant threat to global public health".

He said the recent detection of an H5N1 case in a child returning to Australia from India "underscores the looming pandemic risk".

He said understanding the virology and pathogenesis of avian influenza is crucial for tracking the virus's evolution, developing effective vaccines, and implementing appropriate public health measures.

"Avian influenza viruses can be classified as highly pathogenic (HPAI) or low pathogenic (LPAI) based on their ability to cause disease in poultry. H5N1 is considered the most pathogenic HPAI strain, causing severe infections and high mortality rates," he said.

"Continuous surveillance is essential to monitor the virus's genetic mutations and potential for human-to-human transmission."

According to the World Health Organization, from 2003 to mid-2023,there has been 878 human cases of H5N1, resulting in 458 deaths across 23 countries.

Analysts say it is only a matter of time before H5N1 arrives in Australia.

The government has established a comprehensive framework to confront the potential threat of H5N1, including stringent biosecurity measures, vaccination strategies, and robust public health infrastructure.

"However, systemic challenges in other parts of the world and the rapid pace of globalization pose formidable hurdles. International cooperation and resource allocation are crucial to prevent H5N1 from developing into a full-blown global crisis," Balasubramaniam, at Monash University, added.

Esterman, from the University of South Australia, said the current outbreak of bird flu in Australia involves "different highly pathogenic avian influenza strains" – H7N3, H7N9, and H7N8).

"The outbreaks are more geographically widespread and involve several different strains of avian influenza compared to previous outbreaks (in Australia)," he said.

"The H5N1 bird flu is highly pathogenic for birds, and for the small number of humans infected over the last 20 years, the case fatality rate has been high …about 50 percent."

He said the current worldwide H5N1 outbreak has affected a wider range of bird species than previous outbreaks and has led to significant losses in both wild bird populations and poultry flocks worldwide.

Professor Robert Booy an infectious diseases and vaccine expert with an honorary professorship at the University of Sydney told China Daily that despite three different strains of bird flu now in Australia, the "key issue is that it (bird flu) is not easily spread between humans. And that remains the case".

He said stockpiling of antivirals is again on the agenda in some countries such as Finland and the United States.

"Australia," he said, "has some onshore abilities to develop and produce appropriate vaccines, but this needs more attention."

Balasubramaniam said, while the Australian government has allocated A$7 million ($4.6 million) to address the potential incursion of the H5N1 strain, "I would like to strongly argue that this funding is inadequate given the scale of potential devastation."

The H7 strain currently affecting poultry farms in Australia has led to the culling of approximately 1.8 million commercial birds and incurred costs that exceed A$40 million.