Snake bites kill tens of thousands of people around the world each year. However, we still use techniques invented in the late 19th century to make antivenom, and each bite needs to be treated with antivenom for that specific type of snake.
In this episode of The Conversation Weekly podcast, we hear from two scientists whose recent breakthroughs – and failures – could save many more lives and help achieve the holy grail: a universal antivenom.
“Antivenom is a very, very old medicine,” says Stuart Ainsworth, an expert on snake antivenom at the University of Liverpool in the UK. Today, it’s predominantly made using a technique developed in the 1890s: a snake is milked for its venom, and then a tiny amount of that venom that’s not enough to be toxic is injected into a large animal, usually a horse. Over a period of months, the animal will start building up antibodies to the snake’s venom. The animal’s blood is then drawn and the antibodies purified out to make antivenom.
But Ainsworth explains that the holy grail is a universal antivenom that could work against multiple types of snakebite at the same time.
If you’re in Kenya, there’s 26 different medically important venomous snakes. People who get bitten and people who treat people that get bitten are not snake experts … they’re not going to go, ‘Oh, that was an eastern green mamba, or was it a Jameson’s mamba?’ They’re going to say it was a big snake.
Developments in modern biotechnology are allowing researchers to use new ways to grow what are called monoclonal antibodies in laboratories. These more potent antibodies have fewer side-effects and can neutralise snake venom toxins without having to immunise herds of animals.
Ainsworth and his colleagues had some recent success doing this for a particular type of neurotoxin which targets the nervous system. They did this by hunting through huge libraries of antibodies until they found one that would bind to and neutralise the neurotoxin. It worked when they tested it and the antivenom was able to prevent paralysis and death in mice.
For a universal antivenom, what you’re going to need is a cocktail of multiple different monoclonal antibodies that can all do basically the same thing within their class: recognise lots of toxins and neutralise lots of them.
Other research teams are also using similar techniques to find antibodies for other types of snake venom. But it’s a long process, and some scientists are hitting unforeseen hurdles.
One researcher, Christoffer Vinther Sørensen at the Center for Antibody Technologies at the Technical University of Denmark, thought he’d found a possible antivenom candidate for a venomous pit viper called the Bothrops asper. But when his team simulated a real life envenoming using lab-grown muscle tissue, and then injected the antivenom afterwards, it actually made the venom more potent.
“We’ve discovered this new trapdoor you can fall through right before the end goal,” Sørensen explained. He published the failure in a journal article in the hope that other researchers could learn from it.
If we could ensure that other researchers maybe only waste one year on their molecules that will fail in the end, then we should get a better antivenom faster in the future.
Listen to Stuart Ainsworth and Christoffer Sørensen speaking about their research on The Conversation Weekly podcast, which also features Natasha Joseph, commissioning editor at The Conversation in Africa.
A transcript of this episode will be available shortly.
This episode of The Conversation Weekly was written by Gemma Ware and produced by Mend Mariwany and Katie Flood. Sound design was by Eloise Stevens, and our theme music is by Neeta Sarl. Stephen Khan is our global executive editor and Soraya Nandy does our transcripts.
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