Indian Cobra (Naja naja) has become the first of the ‘big four’ deadly snakes globally to be sequenced.
Researchers have successfully mapped the genome of this highly poisonous snake and decoded 19 key toxic genes that are responsible for its venom that is among the most noxious toxins in the animal kingdom - potent enough to fell an elephant.
Russell’s viper (Daboia russelli), saw-scaled viper (Echis carinatus) and common krait (Bungarus caeruleus) are the other three in the ‘big four’ camp.
The genome sequencing of the Indian cobra is expected to help the scientists develop better antivenom and mitigate the snakebite crisis across the countries particularly India which reports around 2.8 million snakebite cases that lead to about 50,000 deaths annually.
“Targeting these 19 specific toxins using synthetic human antibodies should lead to a safe and effective antivenom for treating Indian cobra bites” said Dr Sekar Seshagiri, President, SciGenom Research Foundation (SGRF) and lead author of the study published in the latest edition of Journal Nature Genetics.
Currently, antivenom is produced by immunizing horses with extracted snake venom and is based on a process developed well over 100 years ago. This process is laborious and suffers from a lack of consistency leading to varying efficacy and serious side effects. Venom is a complex mixture of proteins encoded by genes that have been co-opted by some snakes as they evolved some 100 million years ago.
Globally each year, accidental contact with snakes leads to over 100,000 deaths while over 400,000 individuals suffer permanent disabilities
“It is about time we modernize antivenom development by leveraging genomics, recombinant protein expression and synthetic antibody development technologies. The Indian cobra genome and the catalogue of target toxins are a blueprint needed to do this. For the first time, we now have a full list of venom-relevant toxin genes of the Indian cobra” said Dr R Manjunatha Kini, Professor, National University of Singapore (NUS), Singapore and an author on the study.
“The Indian cobra is the first of the ‘big four’ deadly snakes to be sequenced. This is a major step towards understanding its venom components and it will effectively change the way antivenom is developed” said Dr George Thomas from AgriGenome Labs, India. He further added, “This study has provided a very high-quality reference genome that will make assessment of the Indian cobra genetic diversity possible and practical. It will be an important resource for conservation of this revered and feared Indian snake”.
“Obtaining the genomes and the venom gland genes from the other three of the ‘big four’ and the deadly African snakes such as the black mamba, carpet viper and spitting cobras is the logical next step. It will provide a complete platform for developing a safe, universal antivenom for snakebite victims all over India, Africa and other neighbouring countries” added Dr R Manjunatha Kini.
Safe and effective antivenom is a major unmet social need in India and other parts of the world. With the WHO classifying snakebite as a neglected tropical disease (NTD) in 2017, institutions such as the Welcome Trust and the Department of Biotechnology, under the Union Ministry of Science and Technology have announced funding for antivenom development here.