This year, many thousands of people in sub-Saharan Africa will die from snake bites. Thousands more snake bite survivors will be left with permanent disabilities. Changing those grim statistics is the goal driving a team of researchers from the Liverpool School of Tropical Medicine (LSTM). They're working to develop a novel ‘universal antivenom’ effective against the bite of every dangerous snake in sub-Saharan Africa.
In places where few venomous snakes are to be found, treating a serious bite is far less of challenge than it is in many African countries. In the UK, for example, home to only one native species of venomous snake, identifying a bite culprit is much easier – and that means doctors can quickly select and administer an antivenom intended specifically for the bite of the snake species responsible. This type of treatment is more effective and carries less risk of side effects. On the African continent, things are very different.
“There are over 20 species of deadly snakes in sub-Saharan Africa and doctors often rely on the victim’s description of the animal to help them decide which treatment to administer,” explains lead scientist on the project, Dr Robert Harrison.
When there is no snake ID, doctors are often forced into a cover-all-your-bases approach in order to account for all of the dangerous snakes in the region – a tactic that comes with a whole set of problems.
“[A] broad-spectrum, or poly-specific, antivenom [covers] all the possible snake species that could be responsible. Because these treatments are generally not very effective against any one species, the doctor therefore administers many vials [of antivenom]. However, each dose carries a risk of serious side effects and this risk increases with each additional vial,” Harrison says.
And what makes these treatments so ineffective? It's the way they're made. Venom is ‘milked’ from several snake species before low doses of it are injected into horses or sheep, triggering an immune response. The animals produce antibodies, which are then purified from their blood to create antivenom. Using multiple snake species, however, means that only a small amount of antibody is produced to any one species – and that makes for weak anti-venom.
In addition, administering many vials (at up to $140 per vial!) pushes the cost of treatment way beyond the reach of the impoverished victims who need it most. "People in these very disadvantaged communities are living with snake bites on a daily basis – snake bite is a continuous risk to their lives," Harrison tells the BBC.
So how do you go about making a treatment that's both more potent and more affordable? You start by importing some snakes. "We've imported snakes from various regions of northwest and southern Africa into our facility [and] we're extracting venom from those animals. We've got, at last count, just over 450 specimens of 26 different species of snakes," says Harrison. That inventory includes arguably Africa's most-feared snake, the black mamba.
All that extracted venom is the basic resource Dr Harrison’s team needs as they go about researching and developing the new treatment, using a pioneering new technique called ‘antivenomics’. "Not only do we expect that our anitivenom will be cheaper, safer and much more effective than anything else, but it will [also] be able to be used anywhere in sub-Saharan Africa – this makes it unique."
And unlike other antivenoms that need to be refrigerated during transport and storage, the researchers want their end product to withstand the African heat, a feature that would make it much more suitable for use in remote rural areas without access to electricity.
“Snakebite, like so many neglected tropical diseases, hits those living in the poorest communities the hardest ... While serious, [it] is a perfectly treatable condition given the right tools, which this innovative project promises to deliver.”
Watch the full BBC video on the project here.
Top header image: Joachim S. Müller, Flickr
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