Researchers discover affordable antidote for cobra bites

Scientists from the University of Sydney and Liverpool School of Tropical Medicine have discovered that heparin, a commonly used blood thinner, can be repurposed as an inexpensive antidote for cobra venom.

 Cobras kill thousands and severely injure many more each year, with venom-induced necrosis often leading to amputation. Current antivenoms are costly and ineffective against local necrosis.

“Our discovery could drastically reduce necrosis injuries from cobra bites and might also slow the venom, improving survival rates,” said Professor Greg Neely, a corresponding author of the study from the Charles Perkins Centre and Faculty of Science at the University of Sydney.

Using CRISPR gene-editing technology, an international team identified ways to block cobra venom. They found that heparin and related drugs can stop the necrosis caused by bites.

Published in Science Translational Medicine, the study shows that heparin, an inexpensive and widely available drug, could be quickly implemented after successful human trials. “Heparin is a WHO-listed Essential Medicine and could become a cheap, safe, and effective treatment for cobra bites,” said lead author Tian Du, PhD student at the University of Sydney.

The team discovered that enzymes producing heparan and heparin are crucial for venom to cause necrosis. By flooding the bite site with ‘decoy’ heparin sulfate or related molecules, the antidote binds to and neutralises the venom toxins, preventing tissue damage.

Professor Nicholas Casewell from the Liverpool School of Tropical Medicine highlighted the significance of this discovery for low- and middle-income countries, where snakebites are a major health issue. “Current antivenoms are largely ineffective against severe local envenoming, leading to significant disability,” he said.

Snakebites cause up to 138,000 deaths annually, with 400,000 more suffering long-term consequences. In parts of India and Africa, cobra species are responsible for many incidents.

The World Health Organization aims to halve the global burden of snakebites by 2030. Professor Neely hopes this new antidote will help achieve that goal and reduce death and injury in the world’s poorest communities.

The research team uses CRISPR technology to identify and block genetic targets of venoms. This approach also led to an antidote for box jellyfish venom in 2019.

Professor Casewell’s Centre for Snakebite Research & Interventions has over 50 years of expertise in improving antivenom treatments and understanding snake venom biology. The centre hosts leading experts and the UK’s largest collection of tropical venomous snakes.

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