An international consortium of scientists has successfully decoded the genome of the Indian cobra, consequently identifying the genes in its venom. With this discovery, scientists hope to develop effective antivenom. The effectiveness of the present antivenom varies and they also have side effects. The decoded genome of Indian cobra was published in a paper published this week in Nature Genetics. The paper was authored by 42 scientists, including some from India, led by Dr Sekar Seshagiri, the president of SciGenom Research Foundation in Bengaluru. Accidentally coming in contact with poisonous snakes cause around 1,00,000 deaths every year. India accounts for 50% of these.
The big antivenom challenge in India
The biggest challenge in India is to develop an antivenom for the big four – Indian cobra, common krait, Russell's viper and saw-scaled viper. These big four snakes are responsible for most of the deaths caused by snakebites in India. Currently, a common antivenom is in the market to treat the bites of the big four snakes. However, the effectiveness of the antivenom was questioned in a separate study published last month.
The common antivenom was found to work against the saw-scaled viper and the common cobra. However, it does not work as desired against the bites of some neglected species or against the common krait – one of the big four. The development of an effective antivenom is currently difficult as a snake's venom is made up of around 140 proteins.
However, only some of them are responsible for the physiological reactions that break out after a snakebite.
No antivenom currently targets these specific toxins as it is developed using an age-old method. Venom is extracted from the snake and injected into a horse or a sheep, which then produces antibodies. These antibodies may or may not be relevant as a horse has other antibodies in its body.
Talking to IE, Seshagiri said that another problem with horse antibodies is that the human body treats the horse antibodies as a foreign element and mounts its own antibodies when injected with the antivenom. Moreover, he said, if a person gets bitten by another snake and is administered an antivenom, the person would have a severe allergic reaction.
How will the study help?
The scientists have identified 19 genes which cause physiological reactions, and thus should be the only toxins that are relevant in developing the treatment for snakebites. Using this knowledge, an antivenom can be developed using synthetic antibodies which would be a safe and effective treatment against the bites of the Indian cobra, Seshagiri told IE.
After this, a possible follow up could be decoding the genomes of the remaining three big four snakes and developing a possibly common antivenom for all four.