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Snakebite

Mitigating the chronic burden of snakebite: turning the tide for survivors

The International Snakebite Awareness Day has taken place annually on Sept 19 since 2018. Snakebites kill an estimated 137 880 people each year and three times as many survivors live with life-changing disabilities. ,,Since 2018, there has been some increased funding for research and development of antivenoms and other therapies. But there is a pressing need to additionally focus on the chronic aspects of snakebite care. The WHO strategy for snakebite envenoming aims to decrease not only mortality but also morbidity by 50% by 2030.

In a comment piece in The Lancet three of our network members (Soumyadeep Bhaumik, Maya Gopalakrishnan, Priti Meena) highlights the chronic manifestations of snakebite and propose a system-oriented approach with multi-component interventions to address chronic aspects of snakebite care, together with social support and investments in multidisciplinary research to end the neglect of snakebite.

Read The Lancet article which highlights that the NTD community’s goal to “end the neglect” can be truly achieved in the snakebite domain only if
snakebite survivors are at the centre of the response here (free but needs registration by e-mail) .

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Snakebite

Promoting co-existence between humans and venomous snakes

Studies of snake biology has largely focused on its taxonomy and venoms. Several other aspects of snake biology, including but not limited to behaviour, spatial ecology , distribution, and demography, is not well studied. A new review published by researchers from several countries including Vishal Santra, a member of the Snakebite Research Network, illustrate how demographic, spatial, and behavioural studies can improve our understanding of why snakebites occur and provide evidence for prevention strategies. The review identifies large gaps that remain to be filled and calls for open sharing of data and metadata in public repositories to enable replication and meta-analyses.

Read the full study published in Toxicon X here .

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Snakebite

A compendium of snakes in India

Snakes are fascinating creatures and play a vital role in our ecosystem. On World Nature Conservation Day 2021 we present a compendium listing all 332 snakes in India compiled by Vivek Sharma . It is handy and can serve as a ready reckoner. The same is also available as an Android App together with images and information on whether a snake is venomous or not here

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Snakebite

Ignorance is not bliss: a perspective on the neglected snakebite problem in India

Agriculture is the primary occupation of around 58% of the Indian population. Over the past few decades, agricultural communities have been bearing the brunt of human-animal conflicts arising due to the destruction of natural habitats and wildlife corridors. While wild deer and boars can be a huge menace for food crops, large mammals, such as elephants, can also pose a threat to the lives of the poor farmers. But in addition, amongst the bushes and vegetation, leaves and firewood, lurk the unforeseen peril – the deadly snakes.

In my Indian household, I grew up listening to innumerable mythological tales on snakes. While many of them portrayed snakes as gods, some depicted them as evil and vengeful demons. Snakes have always played an indispensable role in the Indian agroecosystem by controlling the population of rodent pests and protecting food crops from damage. Yet snakes are often synonymised with fear because a snakebite is synonymous with death. As per the report published in 2020, even in the age of artificial intelligence, over 58,000 people die annually due to snakebites in India. A shocking 90% of the total snakebite deaths happen in Indian villages and most victims inhabit the poorest, remote locations that are deprived of basic health facilities, preventing them from accessing appropriate treatment on time.

The cause and effect

India is a biogeographically diverse country, harbouring a variety of flora and fauna distributed across distinct agroclimatic zones. While over 300 species of snakes have been described to this date, only ~60 species could be potentially harmful to humans. Russell’s viper (Daboia russelii) is one amongst those species and is solely responsible for nearly half of the snakebite casualties and disabilities in the country. Predominantly a rodent specialist, D. russelii are often encountered near farmlands and human habitats that serve as bounteous sources of rodents. Snakes actively inject their venom through specialised fangs, for offence and/or defence. Venoms are complex concoctions of deadly toxins (mostly proteins) that target different organs and physiological systems, acting rapidly to immobilise prey or deter a predator. However, when uninformed humans venture out barefoot, particularly after dusk (or) without flashlights, they step on an unsuspecting snake. Though the snake often retreats in fear or strikes back by delivering a dry bite, one unfortunate moment of negligence leads to deadly envenomation.

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Snakebite envenomation is a medical emergency that requires immediate clinical intervention, and the delay in treatment often leads to irreversible morbidities or mortality in extreme cases. But several impoverished communities remain blinded by local faiths and adopt superstitious healing practises over the scientifically proven antivenom therapy. Additionally, there are delays associated with the lack of transportation facilities, under-equipped health-care centres, inexperienced clinicians, and unavailability of sufficient antivenoms, which risk the lives of hundreds of thousands of victims.

The acknowledgement and advancement

Studies from our lab at the Centre for Ecological Sciences, Indian Institute of Science, Bengaluru, have revealed disturbing inefficacies in the current antivenom therapy, particularly due to lack of research integrating the biological, preclinical, and epidemiological aspects of snakebite. Therefore, we, at the Evolutionary Venomics lab, headed by Dr Kartik Sunagar, are employing a multidisciplinary approach to address various aspects of this problem. In addition to employing state-of-the-art research, we are actively collaborating with herpetologists, the major commercial antivenom manufacturers, and scientists from a diversity of backgrounds across the globe for the development of effective and affordable snakebite therapeutics. We also hope to convene clinicians, NGOs, governmental bodies, and global health policymakers to advocate for infallible strategies for mitigation of snakebite problem in India. Though the COVID-19 lockdown has currently deterred the progress of our monsoon sampling schedules, lab work and advocacy programmes, we are constantly involved in public outreach, which is an integral part of snakebite management. 

Having lived all my life in a metropolitan city, I was oblivious to the magnitude of the snakebite problem and challenges in snakebite mitigation until I stepped into the Evolutionary Venomics Lab. Despite the technological, cultural, and economic advancements, rural India remains to be the snakebite hotspot of the world due to lack of awareness and acknowledgement from other sections of the society. Therefore, I believe that initiating a conversation and educating the Indian society about the persistent snakebite problem is the need of the hour. Though we are focussed on battling the global pandemic together, it is also essential to spare a thought for thousands of bite victims. Certainly, the heart-wrenching stories of the indigenous agricultural families about the irrevocable loss of lives, limbs, and livelihood, accentuate that our ignorance is not bliss!

Author profile:  Senji Laxme is a PhD student working at Evolutionary Venomics Lab, Indian Institute of Science, Bangalore on deciphering the influence of ecology and environment on the evolution of snake venoms for the development of recombinant antivenom therapeutics in India.

This blog was originally published here. The blog is licensed under a Creative Commons Attribution-NonCommercial 4.0 International Licence. View a copy of this licence at https://creativecommons.org/licenses/by-nc/4.0/

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Clinical evidence synthesis Morbidity Public Health Snakebite

Depression & PTSD in snakebite survivors: need for more research

Snakebite is a neglected tropical disease that causes death and disability, particularly in rural and tribal people in South Asia, Africa and Latin America. Death, permanent disabilities and long-term physical sequalae due to snakebite has been much discussed and talked about. But are there any mental health manifestation in snakebite survivors?

Keen to understand this better, I got together with other colleagues from the George Institute of Global Health, India to conduct a global review of existing research evidence on the same. The idea was to get information on all we know about mental health in snakebite survivors – its epidemiology, risk factors, burden estimates, or anything around its prevention or management. Hence, we chose a scoping review approach of evidence synthesis.

 Through our research, published recently in BMJ Global Health, we found that there is not much understood with only a handful of papers on the same (including case reports). We found that studies have reported post-traumatic stress disorder (PTSD) and depression in 8% to 43% and 25% to 54% of snakebite survivors, respectively. There was only one study modelling the DALYs lost due to mental health conditions in sub-Saharan Africa and only one randomized controlled trial on the issue.  

Our research clearly shows that depression and PTSD are major causes of morbidity in, but it remains understudied and underexplored globally, including in India and Pakistan, which has the highest burden of snakebite (amounting to  almost half of the global snakebite deaths). There are studies from northern Bangladesh and Sri Lanka but none from these countries in South Asia with high burden. In general, mental health professionals are scarce in countries with high burden of snakebite. This implies apart from understanding the burden and risk factors of mental health manifestations of snakebite, there is also a need for research to understand how this can be dealt by resource-strained health systems. Screening tools for mental health conditions in snakebite patients, particularly those which can be used in primary care are an important which need to be researched on. There is a need for more research on understanding the neglected aspect of morbidity of snakebite.

About the author: Soumyadeep Bhaumik is a medical doctor and international public health specialist working in The George Institute for Global Health. He is the National Convenor of the Snakebite Research Network. Views are personal and might not necessarily be subscribed to author’s institution, funders or the Snakebite Research Network .

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Snakebite

Research on composition of snake venom raises questions about snakebite treatment in India

A recent study led by members of our network , from Centre for Ecological Sciences , Indian Institute of Science, Bangalore, found that the venom of Russell’s vipers shows differences in composition and toxicity based on the geographical location. They also found that the commercial antivenom treatment for Russell’s viper venom works as marketed for most populations of this snake, except in North India. This in contrast to a study published a few months ago on spectacled cobra by the same authors, which showed similar variation in venom based  on location, but the preclinical effectiveness of commercial antivenoms was not found to be not effective against most populations.

Kartik Sunagar the senior author of the study says , “We show that you cannot really predict the clinical or preclinical outcomes just by observing venom variation across populations. Instead, well-designed clinical and preclinical studies are the only way to accurately test the effectiveness of commercial antivenoms.” 

In order to ensure that antivenoms are more effective against variants of snake venom, researchers highlight the need for production of region-specific antivenoms. Senji Laxme, Suyog Khochare and Saurabh Attarde, who are the joint first authors in these studies said that, “Research outcomes of the spectacled cobra and Russell’s viper studies, and our previous work on the ‘neglected many’ suggest that the commercial antivenom fails to neutralise the venoms of three of the big four snakes in the north Indian regions. Coincidentally, these regions are among the major snakebite hotspots in the country. To ensure effective snakebite mitigation, the development of regional antivenoms with venoms sourced from the medically important snakes of the respective regions is the need of the hour “.

Preclinical inefficacy of Indian antivenom therapy in snakebite hotspots.

References:

RR Senji Laxme, Saurabh Attarde, Suyog Khochare et al. Biogeographical venom variation in the Indian spectacled cobra (Naja naja) underscores the pressing need for pan-India efficacious snakebite therapy, PLoS Neglected Tropical Diseases (2021).

RR Senji Laxme, Suyog Khochare, Saurabh Attarde, et al. Biogeographic venom variation in Russell’s viper (Daboia russelii) and the preclinical inefficacy of antivenom therapy in snakebite hotspots, PLoS Neglected Tropical Diseases (2021).

Sections of the note are from the IISc press release which can be read here.