08-07-2025
Australia scientists closer to Hendra virus vaccine thanks to nanobodies from Chilean alpaca names Pedro
An unlikely hero has emerged in the fight against the "absolutely terrifying" Hendra virus, which has again reared its head in Southeast Queensland, killing a horse for the first time in three years.
Hendra — named after the Brisbane suburb that saw its first outbreak in 1994 — is highly lethal to horses and humans.
The hero, 12,000 kilometres away, is Pedro, an eight-year-old Chilean alpaca living in South America.
"His story is quite unique," said Dr Ariel Isaacs, an infectious diseases virologist at the University of Queensland, who used the alpaca in his latest Hendra research breakthrough.
"Pedro was gifted by a travelling Tibetan Buddhist master to the Universidad Austral de Chile when he came to visit their facility a few years ago," he said.
Dr Isaacs' and Pedro's worlds collided as a matter of scientific serendipity.
The researcher first collaborated with the Chilean university during the pandemic, while working on a therapy for COVID-19.
"Nanobodies are very specialised antibodies that can neutralise some viruses with very high potency," Dr Isaacs said.
Camelids, including alpacas and llamas, are some of the only species worldwide that have nanobodies.
"If you introduce a part of the virus into an alpaca, it will produce an immune response — and then it well develop nanobodies against that target. And the Chileans had isolated a nanobody that worked against COVID," he said.
The outcome exceeded expectations.
"We were optimistic that this would work but it was even better than we can have predicted," Professor Daniel Watterson, Dr Isaacs' colleague at the University of Queensland, told 7.30.
Professor Watterson oversees a team including Dr Isaacs which makes vaccines and therapies for emerging deadly viruses with pandemic potential.
Professor Watterson said that once Pedro started making nanobodies "we isolated a particular one that had a really high affinity and ability to protect against the virus in-vitro".
"Then we're able to test that in animal models and prove that protects against infection."
Dr Isaacs described it as a "eureka moment", and the Chilean collaborators named the nanobody 'DS90', with the finer details published in the revered Nature Structural and Molecular Biology journal.
Dr Isaacs said with it, they now have the foundation to produce a powerful therapy.
"What we want to do is turn it into a therapeutic treatment that we could eventually give to a human who might be infected by these viruses," he said.
"And so I'm optimistic and I'm hopeful that funding comes through and we're able to take this into the clinic.
"That would be really amazing for me as an individual, and amazing for the community, and for the lab and our collaborators, and for anybody who's affected by these diseases."
The University of Queenland's infectious disease experts are concerned the Henipaviruses will mutate and spillover.
"Nipah virus, for example, is something that is now emerging across Asia, India and Bangladesh in particular," Professor Watterson told 7.30.
There have been cases of possible human-to-human transmissions and "that's where you're seeing potential for really explosive outbreaks", he warned.
There have been 68 Hendra outbreaks resulting in 110 horse deaths since its discovery in 1994, including one in Southeast Queensland last week — the case of a horse that wasn't vaccinated.
The virus is carried by flying foxes and shed in their excrement, and commonly contracted by horses in contaminated pastures, feed or water.
"It is currently estimated that 70 to 80 per cent of bats are seropositive for Hendra virus, and that means that sometime in their lifetime they've carried the virus," Dr Isaacs told 7.30.
"That's the point of concern for us, because it means that it's still circulating within bat populations, and then that means it can still transmit to horses and the horses can transmit to people — and that can cause severe disease.
Dr Peter Reid was the first veterinarian to treat horses carrying Hendra, before anyone knew what it was, back in September 1994.
He described it as an "absolutely catastrophic, horrifying experience".
"It's always traumatic coming out and doing an interview again," Dr Reid told 7.30.
"But I can understand the interest, and if it has the benefit of reminding people how horrendous it was and the ways to stop it happening, that's what I'm all for."
Dr Reid had been called to Williams Avenue in Hendra to attend Victory Lodge, the Brisbane stables of his client and friend, racehorse trainer Vic Rail.
Several of Mr Rail's horses had fallen ill and they couldn't figure out why.
"There were a lot of sick horses and a lot of dying horses I had to put out of their misery by injecting them, and some of them I couldn't inject because they were thrashing around so badly," Dr Reid recalled.
"In the space of 36 hours, I think there were nine horses that died or I had to put down ... it was just catastrophic because I didn't know what was killing them.
"Hendra virus attacks all organs in the body and particularly has focus on the lungs and the brain — so the horses are actually dying because they can't breathe because their lungs are filling up full of fluid.
"We thought it could have been a poison or a toxin — certainly there's been no virus that had ever been known to medical or veterinary science that could do this."
While detectives, health authorities, and scientists scrambled to figure out what had caused the animals' deaths, Mr Rail himself was struck down, showing symptoms similar to the horses.
He's one of four people to have died from the disease since it was discovered — the human mortality rate stands at almost 60 per cent.
"We know the best way to prevent people being infected to stop the transmission from fruit bats and horses to people, and that is by vaccinating the horses.
"It's safe and effective, it breaks the cycle of transmission.
"Don't think that it can't happen to you, because it can."
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