TRANSCRIPT
The deadly H5N1 virus, also known as the bird flu, is showing troublesome signs of evolution.
A new study, made in conjunction by experts from Australian and Asian universities and published in Springer Nature, reveals new outbreaks of the virus in Europe and Africa.
Professor Raina MacIntyre is Head of the Biosecurity Program at the Kirby Institute at the University of New South Wales.
She is an expert in influenza and emerging infectious diseases.
She says bird flu could be the basis for the next epidemic.
"It's always been the fear that one day, one of these highly pathogenic avian flu viruses will mutate to become easily transmitted between humans. And there's a lot of red flags around one particular clade, as we call it, of the H5N1 that's been spreading in the last year or two."
The first outbreaks in H5 viruses were documented in 2014.
Professor Michael Ward is Chair of Veterinary Public Health & Food Safety at The University of Sydney.
He explains how the virus has changed over recent years.
"It rapidly spread across Asia and Europe and Africa and that was thought to be as a result of the virus taken by wild birds that migrate across continents. So it spread quite rapidly and that might've been associated with changes in the virus. And then lately we've seen, in the last 3-4 years, we've seen another change in this virus. We're seeing these ongoing outbreaks that are occurring in particularly northern Europe but also in the US."]]
The study goes on to reveal that the H-5 virus has mutated, moving away from Asia where it is said to have originated.
A potential outbreak in Australia, while unlikely, could cause significant issues.
Professor Ward says other countries affected by the virus faced major problems in their food chains.
"Trying to control the disease led to a lack of poultry products. A lack of meat and eggs. So, it had that consequence, the supply dried up very quickly because the authorities were trying to control the disease. So, that's the problem. The disease also can be quite devastating when it gets into poultry flocks. It can kill a lot of birds. So you also have that impact as well."
So what are the ways that being used to control the disease?
Dr David Muscatello is an epidemiology expert with the University of New South Wales.
He says there are two ways to stop the bird flu.
"There are two main methods, as I understand, particularly in domestic animal or agricultural applications: culling the populations of the animals that have been exposed to the virus or potentially exposed to the virus; or vaccinating the birds or the animals against the virus. And vaccination is being used more and more, as I understand it, in the animal populations."
But Professor Ward warns the second method carries with it significant risks.
"The problem with vaccination is, you could potentially make the situation worse if then you're starting to get other viruses mixing with the wild viruses. So, countries have been reluctant to do that."
Dr Muscatello explains one of the most troublesome things about the H5 viruses.
"Influenza viruses are constantly evolving and they evolve very easily. So the viruses are continuously circulating in animal, bird and human populations and they're always evolving. And probably the best evidence of that is that we need to change our human influenza vaccines every year."
Bird flu symptoms in humans aren't really all that different from the common flu, as the University of New South Wales' Professor McIntyre explains.
"It presents with typical, influenza-like illness, so high fever, feeling really unwell, aches and pains, respiratory symptoms like cough and shortness of breath."
However, this particular strain of the virus could have some very serious differences in the way it attacks the immune system.
Professor McIntyre goes on to explain what makes the H5N1 strain so dangerous.
"So we see things like seizures, unsteady walking, very prominent neurological symptoms. So it is quite conceivable that if this particular strain, which is called clade 2.3.4.4 b, of H5N1 mutates to infect humans easily, we may see very prominent neurological symptoms, as well as the respiratory symptoms."
One way to prevent the possibility of a future pandemic is by keeping a watchful eye on how the virus continues to evolve.
Professor McIntyre says her team at UNSW has come up with an innovative way to do that.
"A way to mitigate that is early warnings and early detection. And we've developed an early warning system at UNSW called "epi-watch" where we actually report on any undiagnosed severe acute respiratory illnesses that are occurring particularly in hotspots of the avian survirus. Because that's exactly how it's going to present. You'll see lots of avian flu virus in animals and birds, and then suddenly you'll start seeing clusters of pneumonia, just like it started in Wuhan in 2020-late 2019."
