Snakes have long been revered and worshipped in India. Although not everywhere, this status of reverence in large parts of the country has meant snakes have been able to thrive in India. However, the protected status, the consequential high population, and the diversity of snake species have also meant a higher number of snakebites in the country, especially in rural areas. The ‘big four’ - Russell’s viper, saw-scaled viper, krait, and Indian cobra, are responsible for most of the snakebite incidents.
A new study has now shed light on a concerning issue: the antivenom used to treat bites from the saw-scaled viper (Echis carinatus sochureki) isn't as effective as it should be in certain regions. A team from the Indian Council of Medical Research (ICMR) studied data from a centre treating snakebite victims in Jodhpur, Rajasthan. They found that many patients bitten by the saw-scaled viper weren't responding well to the standard Indian polyvalent antivenom.
Antivenom is a unique mixture made from the antibodies of animals (usually horses) that have been exposed to snake venom. The polyvalent antivenom is designed to work against the venom of the big four snakes, including the saw-scaled viper. When a person is bitten by a venomous snake, the venom can cause a range of problems, from tissue damage and bleeding disorders to paralysis and even death. Antivenom works by binding to the venom in the body and neutralising its harmful effects. Ideally, it should quickly reverse the effects of the venom, allowing the person to recover fully.
In their study, the team wanted to investigate the clinical characteristics, outcomes, and effectiveness of currently available Indian polyvalent antivenom in managing saw-scaled viper envenoming. To this end, they conducted a study on data from April 2019 to April 2024 at a tertiary care centre in Jodhpur involving 210 patients who had been treated for snakebites. They collected demographic details, bite geo-location, bite-to-antivenom time, antivenom dose, coagulation profile, mortality, and duration of hospital stay. Of the 210, 105 were confirmed to have been bitten by a saw-scaled viper, either by identifying the dead snake or through photographs or based on diagnosis of the symptoms based on WHO criteria.
The study found that over two-thirds (68.4%) of the patients who received antivenom didn't respond as expected. 103 of the 105 patients experienced venom-induced consumption coagulopathy (VICC), where the venom caused their blood to clot abnormally, leading to bleeding. Around 35% of patients also experienced local and specialised bleeding at the bite site and in other parts of their bodies. Meanwhile, 3 out of 4 patients (75.7%) also experienced delayed Hypofibrinogenaemia, where their body wasn’t producing enough fibrinogen, a protein essential for blood clotting, even days after the bite. The researchers also found that patients who were bitten in certain areas (the ‘West zone’ of Rajasthan) and those who received higher doses of antivenom were more likely to be unresponsive.
The researchers believe the most likely reason for the antivenom's ineffectiveness is that the venom of saw-scaled viper in Rajasthan is different from the venom used to produce the antivenom. Most of the venom used to make India’s polyvalent antivenom comes from saw-scaled vipers in South India. Snakes from different regions can have variations in their venom composition. This means that the antibodies in the antivenom may not bind as effectively to the venom of the vipers in Rajasthan, leaving the venom free to cause damage.
The researchers suggest that the most urgent need is to develop a region-specific antivenom tailored to the venom of Echis carinatus sochureki, the saw-scaled viper in Rajasthan and other regions. This would involve collecting venom from vipers in the region and using it to produce antivenom.
The research highlights a critical gap in our understanding of antivenom and our methods of administering it. The ineffectiveness of the current antivenom against saw-scaled viper venom is a serious concern that begs the question: Does the antivenom work in other regions? Does it work for other venomous snakebites? A comprehensive analysis is the need of the hour to know how we are fair in combating snakebites and allaying any fears of these magnificent creatures.
This research news was partly generated using artificial intelligence and edited by an editor at Research Matters