Deadly cobra bites to “drastically reduce” as scientists discover new antivenom

Scientists have found that a commonly used blood thinner known as heparin can be repurposed as an inexpensive antidote for cobra venom.

The new discovery could drastically reduce injuries from necrosis – the death of body tissue and cells – caused by cobra bites.

Heparin might also slow the movement of venom, which could improve survival rates, say researchers from The University of Sydney and Liverpool School of Tropical Medicine, who published their findings today in the journal Science Translational Medicine.

Cobras – a common name for various venomous snake species – kill thousands of people a year. Perhaps a hundred thousand more are seriously injured by necrosis caused by the venom, which in some cases can lead to the amputation of limbs.

The discovery was made by a team of scientists based in Australia, Canada, Costa Rica and the UK. Using CRISPR gene-editing technology – a method that can modify precise regions of DNA to treat serious diseases – they successfully repurposed heparin, proving that the common blood thinner can stop the necrosis caused by cobra bites.

Current antivenom treatment doesn’t effectively treat the flesh around snakebites, and it’s expensive, says Professor Greg Neely, a corresponding author of the study from the Charles Perkins Centre and Faculty of Science at the University of Sydney.

Unlike the 19th-century antidote technologies, the heparinoid drugs act as a ‘decoy’ antidote, binding to and neutralising the toxins within the venom that cause tissue damage, the study explains.

The new antidote discovery has other benefits, says lead author of the study Tian Dufrom. “Heparin is inexpensive, ubiquitous and a World Health Organization-listed Essential Medicine. After successful human trials, it could be rolled out relatively quickly to become a cheap, safe and effective drug for treating cobra bites.”

Snakebites kill up to 138,000 people a year, with more than twice that number experiencing long-term consequences of the bite. The study cites snakebites as the deadliest of the neglected tropical diseases. Rural communities in low-income and middle-income countries are the worst hit. In some parts of India and Africa, cobra species account for most snakebite incidents.

The World Health Organization has identified snakebite as a priority, announcing an ambitious goal of reducing the ill effects of snakebites by half by 2030.

“That target is just five years away now, says Professor Neely. “We hope that the new cobra antidote we found can assist in the global fight to reduce death and injury from snakebite in some of the world’s poorest communities.”

The study Du, T. et al, ‘Molecular dissection of cobra venom highlights heparinoids as an effective snakebite antidote’ was published in Science Translational Medicine.

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