Stuart and Belinda Griffin never thought they’d be on the look out for bird flu in their cows.
“It’s a bit of the alert, but not alarmed,” said Stuart whose family has run a dairy farm in Moe, in Victoria’s La Trobe Valley, for more than a century.
The couple have eagle eyes on the events that have been unfolding in the United States’ dairy industry since March.
Victorian dairy farmers Belinda and Stuart Griffin are closely following what’s happening in the US to dairy cows. (ABC News: Andrew Altree-Williams)
In a surprise discovery, the deadliest strain of bird flu — known as Highly Pathogenic Avian Influenza (HPAI) H5N1 — jumped species once again, this time to dairy cows.
The first ever cases in cattle were found in Texas and the virus has rapidly spread with livestock movements to more than 250 herds across 14 states.
Stuart’s initial reaction when he saw the news was empathy.
“My first thought was that would be a really tough situation for those guys,” he told 7.30.
HPAI H5N1 has spread to cattle in 14 states across the US. (ABC News)
“And then the thought turns to, ‘ok, what does that mean here?’ We don’t have H5N1 here yet in Australia, but what if? What do we need to look out for?”
“We’re really lucky in Australia to not be first … we can learn from what’s happened in the US.”
Australia is the last remaining continent yet to detect the highly pathogenic H5N1 strain, however many experts believe it’s not a matter of if, but when.
The mutation called clade 2.3.4.4b is wiping out wildlife across the world, killing tens of millions of animals from Antarctica to the Americas.
Four months ago, subtypes of the different H7 strain hit poultry farms in Australia with devastating consequences — almost two million birds were killed — many of those were euthanised.
Cattle stop producing milk
Andrew Bowman says it’s still unknown how the virus moved from wild birds into cattle in the US. (ABC News)
Andrew Bowman is a veterinary scientist at The Ohio State University and was in Brisbane this week for a major international influenza conference called Options XII where the dairy outbreak was discussed.
Professor Bowman has been studying HPAI H5N1 in cattle both on farms and in the laboratory and said there are still many unknowns about how dairy cattle were infected.
“It’s very clear the virus came from wild birds, so we know it was a wild bird into cattle introduction … how exactly that happened, we’re not exactly sure,” he said.
He said the virus was spreading from at least the end of 2023 to early this year without being detected.
It’s thought the virus was spreading among US cattle undetected since late 2023. (Supplied: Peter Somerville)
“Veterinarians didn’t routinely test cattle for influenza, that was not anywhere on a veterinarian’s radar and so because of that, we had a prolonged period of time where virus was circulating and we did not know that it was in dairy cattle and transmitting between them,” he said.
Despite being infected with clade 2.3.4.4b there has not been mass fatalities amongst dairy cows with the disease.
“Some of those will dry off completely and will stop producing milk,” he said.
“Some of those cows also become very ill, they spike a fever, go off feed, and so that certainly is a health problem for those cows.”
Professor Mark Tompkins says the virus may be spreading between cows via milking machines. (Supplied)
University of Georgia Professor, Mark Tompkins, specialises in infectious diseases and is the Director of the Centre for Vaccines and Immunology.
He said studies are ongoing into how the virus is spreading between cows but a leading theory is that it occurs while milking.
“They finish milking that cow, they’re going to break in another cow, and they will disinfect the teats to try and prevent mastitis, but they’re not disinfecting all the milking equipment every single time,” he said,
“So they could actually just be directly transmitting or infecting another cow just from the milking machine.”
Farmer Stuart Griffin says Australia can learn from what’s happened in the US. (Supplied: Peter Somerville)
He said there are very high viral loads in the milk but pasteurisation has shown to be effective in killing the virus.
“In this sense, we know that, by and large, the US milk supply and the dairy supply is safe.”
Professor Bowman said that drinking raw milk is not advised.
“We’d have to assume that there certainly would be a risk of becoming infected by consuming raw, unpasteurised milk,” he said.
“The recommendation would be to only consume pasteurised milk products.”
Virus passed to humans
Dr Jeremy Farrar says controlling the infection in animals is crucial to reducing the risk of human infection. (ABC News)
In four cases, the virus has been transmitted from cows to dairy workers.
These cases of bird flu in humans have so far been mild, some with conjunctivitis symptoms, and there is no evidence of the virus spreading between humans.
Speaking to 7.30 at the influenza conference, World Health Organisation Chief Scientist, Jeremy Farrar, said each infection raises the risk, which is still considered low for people.
“Every time that an animal influenza jumps across to humans. We worry that, that would then lead to a human transmission and then a human pandemic,” Dr Farrar said.
“The worry is that that virus now becomes adapted to human beings, like we saw with COVID, like we’ve seen with many, many infections in the past.”
He said proactive surveillance, preparedness and cooperation between the animal health and human health sectors are key.
“More countries, small countries should be looking at their dairy populations to make sure that their dairy populations are free,” he said.
“Controlling this infection in the animal sector is absolutely crucial in order to reduce the risk of humans getting infected.”
Vigilance is key
Dr Frank Wong says the risk of Australia experiencing a HPAI H5N1 outbreak similar to the one in the US is low. (ABC News: Andrew Altree-Williams)
If animals are suspected to have the virus, their test samples will be sent to CSIRO’s Australian Centre for Disease Preparedness in Geelong, Victoria.
Research scientist and leading avian flu expert, Dr Frank Wong, works at the centre.
He said the risk of an outbreak of the deadly H5N1 strain in Australian dairy cattle similar to that in the US was low.
“To date that … combination of genes, what we call a genotype, has not been found anywhere outside of the US at all,” Dr Wong told 7.30.
“For that virus to be introduced to Australia it would need to be carried by mechanical means or … have infected wild birds … make it to Australia.”
Justin Toohey says if any Australian farm is found to have the H5N1 strain it would be put into quarantine. (ABC News: Andrew Altree-Williams)
Australian Dairy Farmers’ animal health adviser, Justin Toohey, said education of farmers about the H5N1 strain was occurring.
“For years we’ve been pressing upon dairy farmers the importance of good biosecurity measures for a whole range of diseases, so we are confident that awareness at the dairy farm level is improving, and their biosecurity measures on farm are improving,” Mr Toohey said.
He said an existing emergency response plan would be triggered if the virus was detected on an Australian dairy farm in the future.
“That particular farm would be put into quarantine and no product allowed in the food chain,” he said.
“All animals in all farms in close proximity would probably be, if not quarantined, certainly examined very carefully and tested, and we put in place certain zones to restrict the movement of livestock.”
The federal department of agriculture told 7.30 that it had been preparing for a potential incursion of HPAI H5N1 for many years.
The department of agriculture says it has been preparing for the potential arrival of HPAI H1N1 in Australia. (ABC News: Megan Powell)
It said it was highly unlikely that this H5N1 strain will be introduced into the Australian dairy herd.
“However, if it were to occur, we are confident that our existing emergency management arrangements to detect and respond to HPAI in agricultural production systems would be effective.”
It said the dairy industry has taken part in government-run exercises to prepare for any future outbreak and tailored information is being provided to the sector.
Dr Jeremy Farrar agreed that Australia is well prepared for a potential outbreak – but said vigilance is key.
“It’s important all countries have this animal surveillance going on, not just this year, but next year, the year after, the year after, because if we don’t see something, we don’t know, we don’t know it’s there.”
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