But treatments are costly and inaccessible for many people. Most antivenoms are made by injecting dilute venom into a mammal, such as a horse or rabbit. This results in an immune response, and the animal’s serum is then processed so that it can be injected into snakebite victims to scavenge toxic molecules in their blood. Such treatments typically cost $100-150 (£60-100) per dose, a prohibitive price for many people in developing countries.

But a team led by Claire Komives from San Jose State University has identified a protein from the blood of opossums – animals known for their ability to survive snake bites – that can be produced in large quantities by engineered bacteria, and shows promise as an antivenom.

In studies carried out on venom-exposed mice, those that were given just the venom died within 12 hours, while those that received the same amount of venom but were treated with the opossum peptide exhibited no ill effects. ‘Basically, the venom was completely neutralised,’ explains Komives, who was speaking at the 249th ACS National Meeting & Exposition in Denver, US. The peptide could protect the mice from the venoms of western diamondback rattlesnakes and Russell’s vipers.