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The Hindu
3 days ago
- Health
- The Hindu
Call for region-specific antivenoms to save snakebite victims
Herpetologists and health experts have called for region-specific antivenoms to increase the chances of saving lives in areas where the 'Big Four' snakes are not dominant. Snakebite victims in India are administered a polyvalent antivenom derived from the venom of four serpents that cause the majority of deaths. These four are the Indian cobra (Naja naja), common krait (Bungarus caeruleus), Russell's viper (Daboia russelii), and saw-scaled viper (Echis carinatus). However, the polyvalent serum developed against these four snakes has limited or no efficacy in most parts of Northeastern India, where snakebite deaths are more commonly caused by the monocled cobra (Naja kaouthia), kraits (Bungarus sp.), green pit vipers (Trimeresurus sp.), and other medically significant snakes. 'There is an urgent need to establish a Regional Venom Centre and a serpentarium (a place where snakes are housed for exhibition or research) at a strategic place in the northeast to address the region's unique snakebite challenges and improve patient outcomes,' herpetologist Jayaditya Purkayastha said. He heads Help Earth, a Guwahati-based biodiversity conservation organisation, which partnered the Assam State Biodiversity Board, Assam Forest Department, and the Madras Crocodile Bank Trust (MCBT) to organise the first-ever Assam Snake Symposium a fortnight ago. The event brought together more than 80 snake rescuers from across Assam, alongside national and international experts, researchers, educators, and policymakers. 'Without region-specific antivenom, many envenomation cases result in delayed recovery, long-term complications, or even fatalities, despite the administration of standard treatment. A regional venom centre would serve as a hub for the systematic collection of venom from the medically important species native to the northeast, enabling the development of geographically appropriate antivenom,' Dr Purkayastha said. 'Such a centre, coupled with a serpentarium, can help maintain, milk, and study live specimens ethically. This facility would also support research on venom variability, toxin composition, and clinical manifestations specific to local snake species,' he said. High-burden States A 2020 study on trends in snakebite deaths in India from 2000 to 2019, published in eLife, said the World Health Organisation's call to halve global snakebite deaths by 2030 would require substantial progress in India. It also cited the WHO's estimation that 81,000-138,000 people die annually from snakebites worldwide, and thrice the number survive with amputations and permanent disabilities. The researchers of the study, including Romulus Whitaker, Wilson Suraweera, Geetha Menon, and Prabhat Jha, analysed 2,833 snakebite deaths from 611,483 verbal autopsies in the nationally representative Indian Million Death Study from 2001 to 2014, and conducted a systematic literature review from 2000 to 2019 covering 87,590 snakebites. The team estimated 1.2 million snakebite deaths (average 58,000 per year) across India from 2000 to 2019, nearly half of them occurring at ages 30-69 years and over a quarter in children under 15 years. Most of these deaths occurred at home in rural areas. The study found that about 70% occurred in eight higher-burden States with 55% of India's population, and half during the rainy season and at low altitude. These States are Bihar, Jharkhand, Madhya Pradesh, Odisha, Uttar Pradesh, Andhra Pradesh (before the creation of Telangana), Rajasthan, and Gujarat. 'The risk of an Indian dying from snakebite before age 70 is about 1 in 250, but notably higher in some areas. More crudely, we estimate 1.11-1.77 million bites in 2015, of which 70% showed symptoms of envenomation,' the study said, noting that prevention and treatment strategies might substantially reduce snakebite mortality in India. Overlooked health issue According to the National Crime Records Bureau's report on accidental deaths in 2022, deaths due to 'snakebite' dropped by 3.6% from 10,450 in 2021 to 10,085 the following year. Deaths due to 'killed by animals' and 'animal/reptiles/insects bite' increased by 16.5% and 16.7% during this period, respectively. Despite the 'encouraging' trend in snakebite deaths, reptile specialists pointed out that snakebite envenoming remains a major but often overlooked public health issue in India, which accounts for nearly half of the global snakebite deaths each year. 'India is the world's most affected nation in terms of mortality. The burden is particularly high in rural and agrarian communities, where people frequently work barefoot in fields and lack access to timely medical care,' MCBT's Gnaneswar Ch. said. He said that the snakebite crisis is worsened by several challenges, with many cases going unreported due to reliance on traditional healers, lack of transportation, and limited awareness. 'Delays in reaching health facilities, along with improper first-aid practices, often lead to severe complications or death. Furthermore, there is a shortage of trained personnel and adequate supplies of antivenom in remote areas. The quality and regional suitability of antivenom is another concern, as it may not be effective against locally prevalent snake species outside the Big Four,' he said. In response to this public health emergency, India launched the National Action Plan for Prevention and Control of Snakebite Envenoming in 2024, aligning with the WHO's 2030 target to halve snakebite deaths. The experts agreed that despite such efforts, major gaps remain in public awareness, community preparedness, and healthcare infrastructure. They sought greater emphasis on region-specific research, education campaigns at the village level, and strengthening rural healthcare systems to ensure early and appropriate treatment. Snakebite mitigation Acknowledging the challenges in saving lives in a region where the polyvalent serum is less effective, Assam's forest minister, Chandra Mohan Patowary said a State-Level Steering Committee on Snakebite Mitigation would be formed. He proposed the establishment of a serpentarium in Assam to facilitate advanced research on snake venom and address the region-specific challenges of envenomation and treatment. Subsequently, the Assam State Biodiversity Board signed a memorandum of understanding with Help Earth to work jointly on snakebite awareness and mitigation programmes at the Biodiversity Management Committee level. The experts favoured a State Snakebite Mitigation Action Plan toward setting up a Regional Venom Centre and facilitating collaborations with institutions across India for venomics research and antivenom standardisation. They also suggested an app or digital platform for the timely and ethical handling of snake-human encounters, increasing due to habitat encroachment, urbanisation, and seasonal flooding. Such an app is envisaged to serve as a life-saving tool for both humans and snakes by reducing panic and delays during snake sightings or bite incidents. 'Beyond rescue logistics, the app can act as a centralised repository of real-time data on snake rescue, release locations, species involved, and conflict zones. This valuable information can be used to identify hotspots, monitor trends, and guide policy-level decisions for snake conservation, land-use planning, and public health interventions,' Dr Purkayastha said. 'Moreover, this digital platform can be integrated with hospitals, forest departments, and wildlife boards to streamline responses, improve awareness, and encourage coexistence,' he said. 'Snakebite deaths in India are largely preventable, and with coordinated action across health, forest, and community sectors, the country can move closer to eliminating avoidable snakebite fatalities,' Assam's chief wildlife warden, Vinay Gupta, said.
The Hindu
18-06-2025
- Health
- The Hindu
Two existing drugs offer hope to cure Russell's viper bites
Studies carried out in mice have demonstrated that two approved drugs — varespladib and marimastat — were effective in countering systemic and lethal effects of Russell's viper (Daboia russelii) venom either individually or in combination. The two drugs were tested against Russell's vipers venom sourced from different States across India. Russell's vipers are responsible for over half of India's snakebite cases. The study led by Dr. Kartik Sunagar, Professor, Centre for Ecological Sciences at IISc, Bangalore, was published recently in the journal Communications Medicine. Dr. Sunagar and his team are now working with ICMR to design a human clinical trial to test the two drugs. 'During the trial, the drugs will be used as an ancillary treatment to determine how effective they would be in treating snakebites,' he says. The control group control will receive only the antivenom but not the drugs. Phospholipase A 2 (PLA 2 ), and Snake Venom Metalloproteinase (SVMPs) are two main components of Russell's viper snake venom. These toxins interfere with components of the blood clotting cascade to induce anticoagulant and haemorrhagic effects in humans. While the varespladib drug inhibits PLA 2 , the marimastat drug inhibits SVMP. Venom influencing factors 'In a 2021 study, we found differences in venoms of Russell's vipers from across India depending on the biogeography where they were found. In a follow-up study, we showed that diet and development probably had a major influence in dictating the differences in the venom of Russell's viper,' says Dr. Sunagar. 'Another study published recently [April 2025] found that climatic conditions, such as temperature and rainfall, can also indirectly have a small effect on venom variation.' 'In the Western Ghats, characterised by heavy rainfall and dense forests, a rich variety of amphibians and arthropods thrive, providing snakes with a diverse diet. In contrast, arid regions experience limited rainfall and sparse plant cover, resulting in reduced diversity of prey available for snakes,' Dr. Sunagar says. 'Temperature can also influence gene expression, though the extent to which this affects venom variation remains unclear. However, it is likely that temperature changes indirectly alter venoms by affecting the availability of prey composition in the region.' Differences in venom In the latest study, Russell's viper venom from Punjab and Tamil Nadu exhibited the highest PLA 2 activity, followed by other regions — Kerala, Maharashtra, Goa, and Madhya Pradesh. Russell's viper snake venom from all other regions exhibited minimal PLA 2 activity. Proteinase activity was highest in Karnataka followed by the Rajasthan, Madhya Pradesh, Goa, and Andhra Pradesh regions. In contrast, venom from Tamil Nadu exhibited little to no activity, while venom samples from other regions exhibited modest proteolytic activity. Effectiveness of drugs The PLA 2 inhibitor varespladib was found to neutralise even the high PLA 2 activity of the venom found in Tamil Nadu and Punjab. The varespladib drug effectively inhibited the modest PLA2 activity of the venom from other Indian regions. In the case of the matrix metalloprotease-inhibiting drug, marimastat, the drug effectively inhibited the venom in a concentration-dependent manner. The drug was effective even when the proteolytic activity was high, as seen in Karnataka. As expected, the drug exhibited highly potent inhibitory effects against the venom with moderate activity, as seen in Madhya Pradesh, Rajasthan, and Goa. Overall, the drugs varespladib and marimastat when used individually or in a therapeutic drug combination were found to be very effective in reducing venom-induced cytotoxicity, venom-induced coagulopathy, and fibrinogenolysis. When used individually, the drugs were effective in reducing the venom-induced cytotoxicity by snake populations from some regions while being less effective in the case of venom from some other regions. However, the therapeutic combination of varespladib and marimastat nearly completely inhibited these activities. To replicate the real-world scenario and to test the effectiveness of the drugs after the venom challenge, the researchers administered the drug 30 minutes after venom delivery. Rescue experiments involving PLA 2 -rich snake venom from Punjab revealed that the varespladib drug conferred complete protection against venom-induced lethality even when the drug was administered 30 minutes after venom injection. In contrast, marimastat was ineffective in rescue experiments even when the drug was administered soon after venom delivery. In the case of venom from Karnataka, the Marimastat drug provided only 40% survival rate against the SVMP-rich venom at the end of 24 hours even when the drug was administered soon after venom injection. In the case of venom from Madhya Pradesh, which is rich in both SVMP and PLA 2 , varespladib and marimastat individually provided only 60% and 40% protection, respectively, when dosed immediately after venom challenge. But a therapeutic combination of the two drugs conferred complete protection from venom-induced lethality even when the drugs were administered 30 minutes after venom injection. According to Dr. Sunagar, since the body size of mice is extremely small, where they weigh between 18-22 grams, 30 minutes delay in administering the drug is perhaps equivalent to many hours delay in treating patients bitten by a Russell's viper. Designing a trial Even in a single State, the snakes might be producing a different type of toxin in different parts of the State. For instance, in Karnataka, one drug is effective in the southern part of the State, while the other drug is effective in the northern part of the State. 'Given this stark variation in venoms, clinical trials must be conducted across various regions of India. Initially, we will begin the clinical trials in select regions and gradually expand them to cover most areas throughout the country. Once the trials are completed, we will determine which drug(s) are necessary for treatment in each specific region,' Dr. Sunagar says. The targeted approach will help in treating patients with a single effective drug or the drug combination instead of blindly using the two drugs in combination across the country and thereby reducing dose effectiveness.
