Bird flu is nothing to sneeze at

In the past year, at least 10 poultry farms in Victoria, New South Wales, and the Australian Capital Territory have been infected with avian influenza of the H7 strain (H7 bird flu). 

Before you go off to re-boil all your eggs, it is worth knowing that while this is unprecedented, the three strains detected by CSIRO scientists were more closely related to low pathogenic strains known to be carried by Australian wild birds, and were likely to have spilled over from wild birds separately. 

Importantly, the CSIRO has said its information clearly shows these strains were not the HPAI H5N1 strain causing widespread outbreaks in other parts of the world. 

However, lovers of egg-based meals would have observed empty supermarket shelves, in part because of continuing bird flu cases in Victoria. 

Across Australia, about two million hens were killed after the 2024 outbreaks. 

Egg production has slowed, leading to shortages, some buying limits, and price increases. This began in late 2024, and stocks are not yet back to normal. 

Avian influenza is a viral disease of birds found globally, and many low pathogenicity strains that cause no or mild disease circulate in Australian wild birds. Highly pathogenic strains in poultry farms can cause outbreaks of severe disease, resulting in many sick and dead birds.  

And that is what has been found on some Victorian poultry farms, which have been isolated to contain the spread. 

“When you think that there were three outbreaks in 2024, and prior to that only eight outbreaks of H7 bird flu dating back to the 1970s, you can see why this is being taken so seriously,” Frank Wong, senior research scientist at CSIRO’s Australian Centre for Disease Preparedness told The Australian. 

Using advanced genetic testing, scientists showed there were three virus strains causing three separate outbreaks: 

• The H7N3 strain at seven properties in the Meredith area of Victoria.

• The H7N9 strain at one property in the Terang region of Victoria.

• The H7N8 strain at two properties in the Hawkesbury district in New South Wales, and at one property in the Australian Capital territory. 

The CSIRO says that having three separate outbreaks at once was an unprecedented event in Australia. 

Of more concern is the spread overseas of the more dangerous H5N1 strain, which is killing birds and mammals exposed to it. Already more than 350 species of wild birds and more than 50 species of mammals have been infected. 

Dairy farms, zoos, household pets, and some wild animal and bird populations have been severely affected, including sea lions and elephant seals, which eat infected birds. 

If it spread to Australia, “the consequences are likely to be catastrophic”, said Michelle Wille, a virus ecologist based at the University of Melbourne’s Centre for Pathogen Genomics. 

Australia is the only continent the virus hasn’t reached, but experts believe it is just a matter of time. 

Australian governments have increased their preparedness. Last year, the Federal Government announced an additional $100m investment to “strengthen surveillance”.

People can catch avian influenza and the most likely way is through close contact with infected birds, their faeces or feathers. 

Dr Wong says people who are infected “commonly have only mild symptoms such as conjunctivitis or mild respiratory issues, and many have no symptoms at all, though there have been a small number of severe cases”. 

“And humans can’t pass it to humans,” he told a journalist. 

It is reported that previous strains of H5N1 have been much more lethal, with symptoms including pneumonia and encephalitis. 

Around 40 to 60% of those humans worldwide infected with all variants of H5N1 have died. 

“This latest strain does appear to be milder in its effect on humans, though we need to watch out for future mutations,” Dr Wille said.

The Australian Centre for Disease Control advises the risk to Australians is low and bird flu is not a food safety concern.  

All food products in Australia must meet strict food safety production requirements before entering the commercial food chain. This includes testing for diseases like bird flu during outbreaks.  

There is no evidence that people can be infected with bird flu by consuming meat or eggs prepared in line with normal safe food handling practices. 

Learn more about commercial food safety. 

People who spend a lot of time around animals infected with bird flu are at higher risk of being infected themselves, but symptoms are usually mild, and include fever, cough, sore throat, aches, and fatigue. 

Your seasonal influenza vaccination won’t protect against bird flu but it does reduce your risk of being infected with seasonal flu and bird flu at the same time. When viruses have a chance to mix together, they can become dangerous to human health.