Mortality due to snakebite and other venomous animals in the Indian state of Bihar: Findings from a representative mortality study

The need for a refined scorpion antivenom for Iran

Scorpion sting is a medical burden globally but especially frequent hotspots of scorpion biodiversity. In Iran, one of those hotspot countries, many fatalities occur in the South as well as the Southwest and are thought to be caused by Hemiscorpius lepturus. Accordingly, those are used for antivenom production. However, recent surveys revealed that indeed a different species Hemiscorpius acanthocercus is responsible for most accidents in the South, while H. lepturus is primarily causing the fatalities in the Southwest and thus Iranian scorpion antivenom needs to be refined in that respect. Such a refined antivenom would need to cover both species of Hemiscorpius. In response, the Iranian Ministry of Health requested the adjustment of the production line from local antivenom suppliers but until today no action has been taken.

Oral and IV Varespladib Rescue Experiments in Juvenile Pigs with Weakness Induced by Australian and Papuan Oxyuranus scutellatus Venoms

Antivenom is currently the standard-of-care treatment for snakebite envenoming, but its efficacy is limited by treatment delays, availability, and in many cases, species specificity. Many of the rapidly lethal effects of envenoming are caused by venom-derived toxins, such as phospholipase A2 (sPLA2); therefore, small molecule direct toxin inhibitors targeting these toxins may have utility as initial and adjunct therapies after envenoming. Varespladib (intravenous, IV) and varespladib-methyl (oral) have been shown to potently inhibit sPLA2s from snake venoms in murine and porcine models, thus supporting their further study as potential treatments for snakebite envenoming. In this pilot study, we tested the ability of these compounds to reverse neurotoxic effects of venom from the Australian and Papuan taipan (Oxyuranus scutellatus) subspecies in juvenile pigs (Sus domesticus). The mean survival time for control animals receiving Australian taipan venom (0.03 mg/kg, n = 3) was 331 min ± 15 min; for those receiving Papuan taipan venom (0.15 mg/kg, n = 3) it was 178 ± 31 min. Thirteen pigs received Australian taipan venom and treatment with either IV or oral varespladib (or with IV to oral transition) and all 13 survived the duration of the study (≥96 h). Eight pigs received Papuan taipan venom followed by treatment: Briefly: Two animals received antivenom immediately and survived to the end of the study. Two animals received antivenom treatment delayed 45 min from envenoming and died within 4 h. Two animals received similarly delayed antivenom treatment and were rescued by varespladib. Two animals were treated with varespladib alone after a 45-min delay. Treatment with varespladib only was effective but required repeat dosing over the course of the study. Findings highlight both the importance of early treatment and, as well, a half-life for the investigational inhibitors now in Phase II clinical trials for snakebite. Varespladib rapidly reversed weakness even when administered many hours post-envenoming and, overall, our results suggest that varespladib and varespladib-methyl could be efficacious tools in the treatment of sPLA2-induced weakness from Oxyuranus envenoming. Further clinical study as initial therapy and as potential method of rescue from some types of antivenom-resistant envenomings are supported by these data.

The concept of Big Four: Road map from snakebite epidemiology to antivenom efficacy

Snake envenomation is a life-threatening disease caused by the injection of venom toxins from the venomous snake bite. Snakebite is often defined as the occupational or domestic hazard mostly affecting the rural population. India experiences a high number of envenoming cases and fatality due to the nation's diversity in inhabiting venomous snakes. The Indian Big Four snakes namely Russell's viper (Daboia russelii), spectacled cobra (Naja naja), common krait (Bungarus caeruleus), and saw-scaled viper (Echis carinatus) are responsible for majority of the snake envenoming cases and death. The demographic characteristics including occupation, stringent snake habitat management, poor healthcare facilities and ignorance of the rural victims are the primary influencers of high mortality. Biogeographic venom variation greatly influences the clinical pathologies of snake envenomation. The current antivenoms against the Big Four snakes are found to be less immunogenic against the venom toxins emphasizing the necessity of alternative approaches for antivenom generation. This review summarizes the burden of snake envenomation in India by the Big Four snakes including the geographic distribution of snake species and biogeographic venom variation. We have provided comprehensive information on snake venom proteomics that has aided the better understanding of venom induced pathological features, summarized the impact of current polyvalent antivenom therapy highlighting the need for potential antivenom treatment for the effective management of snakebites.

Global mortality of snakebite envenoming between 1990 and 2019

Snakebite envenoming is an important cause of preventable death. The World Health Organization (WHO) set a goal to halve snakebite mortality by 2030. We used verbal autopsy and vital registration data to model the proportion of venomous animal deaths due to snakes by location, age, year, and sex, and applied these proportions to venomous animal contact mortality estimates from the Global Burden of Disease 2019 study. In 2019, 63,400 people (95% uncertainty interval 38,900-78,600) died globally from snakebites, which was equal to an age-standardized mortality rate (ASMR) of 0.8 deaths (0.5-1.0) per 100,000 and represents a 36% (2-49) decrease in ASMR since 1990. India had the greatest number of deaths in 2019, equal to an ASMR of 4.0 per 100,000 (2.3-5.0). We forecast mortality will continue to decline, but not sufficiently to meet WHO's goals. Improved data collection should be prioritized to help target interventions, improve burden estimation, and monitor progress.

An update on epidemiology and management practices of Scorpion envenomation in India

Introduction

Scorpion envenomation is a life-threatening condition, particularly for children. Therefore, it is essential for primary care health providers to suspect, identify, and manage this condition early to prevent death and minimize morbidity.

Objective

To identify the key epidemiological characteristics of scorpion envenomation and update the primary care health workers regarding the latest management practices of scorpion envenomation.

Methodology

A non-systematic review was performed by searching the key terms on databases such as PubMed, Medline, Scopus, Google Scholar, and ResearchGate.

Results

Worldwide, over 2.5 billion people are living at risk of scorpion stings. Every year, over 1.2 million are stung by scorpions leading to the death of at least 3,250 people globally. The most vulnerable group includes farmers, laborers, and those living in rural areas. Adults are most frequently stung but envenomation is more severe among children. Prazosin is a key drug to prevent death due to cardiovascular complications.

Conclusion

Most of these stings and deaths could be preventable with proper awareness, safety precautions, and timely access to treatment. Government and local hospitals should ensure the availability of key drugs such as prazosin.

ICMR task force project- survey of the incidence, mortality, morbidity and socio-economic burden of snakebite in India: A study protocol

Background

Snakebite is possibly the most neglected of the NTDs (Neglected Tropical Diseases). Half of the global deaths due to venomous snakebites, estimated at 100,000 per year, occur in India. The only representative data on snakebite available from India is the mortality data from the RGI-MDS study (Registrar General of India- 1 Million Death Study) and another study on mortality from the state of Bihar. Incidence data on snakebite is available for 2 districts of the state of West Bengal only. Hospital-based data on snakebite admissions and use of ASV are gross underestimates as most snakebite victims in rural India depend more on alternate treatment methods which do not get represented in National registries. The proposed study is a multi-centric study to determine the incidence, morbidity, mortality and economic burden of snakebites in India covering all 5 geographical zones of the country.

Protocol

A community level surveillance for snakebite covering 31 districts in 13 states of India in order to obtain annual incidence of snakebites from the community. Frontline health workers will be trained to gather information on new cases of snakebite over the study period of 1-year, from “wards “(smallest administrative subunit of a village or town) that they represent in the study districts. Dedicated field officers would collect data on snakebites, victim characteristics, outcomes, utilization of health facilities on a questionnaire sheet designed for this purpose. The study duration is for 18 months from April 2022 to October 2023.

Discussion

The study would be the first of its kind in India looking prospectively at the incidence of snakebite covering 13 states in 5 zones of India and a population of 84 million. Our study covers 6.12% of the total population of the country as compared to the incidence study conducted in Sri Lanka which covered 1% of the total population.

Promoting co-existence between humans and venomous snakes through increasing the herpetological knowledge base

Snakebite incidence at least partly depends on the biology of the snakes involved. However, studies of snake biology have been largely neglected in favour of anthropic factors, with the exception of taxonomy, which has been recognised for some decades to affect the design of antivenoms. Despite this, within-species venom variation and the unpredictability of the correlation with antivenom cross-reactivity has continued to be problematic. Meanwhile, other aspects of snake biology, including behaviour, spatial ecology and activity patterns, distribution, and population demography, which can contribute to snakebite mitigation and prevention, remain underfunded and understudied. Here, we review the literature relevant to these aspects of snakebite and illustrate how demographic, spatial, and behavioural studies can improve our understanding of why snakebites occur and provide evidence for prevention strategies. We identify the large gaps that remain to be filled and urge that, in the future, data and relevant metadata be shared openly via public data repositories so that studies can be properly replicated and data used in future meta-analyses.

Prevention and improvement of clinical management of snakebite in Southern Asian countries: A proposed road map

In the Southern Asian countries, snakebite takes a substantial toll in terms of human life, inflicts acute morbidity and long term disability both physical and psychological, and therefore represents a neglected socio-economic problem and severe health issue that requires immediate medical attention. The 'Big Four' venomous snakes, viz. Daboia russelii, Naja naja, Bungarus caeruleus and Echis carinatus, are prominent, medically important species and are the most dangerous snakes of this region; therefore, the commercial polyvalent antivenom (PAV) contains antibodies against the venoms of these snakes. However, envenomations by species other than the 'Big Four' snakes are grossly neglected, and PAV is only partially effective in neutralizing the venom of these snakes. Many issues confounding effective treatment of snakebite are discussed in this review, and these hurdles preventing successful treatment of snakebite must be addressed. However, in South Asian countries, the pre-hospital treatment and appropriate first aid are equally important to mitigate the problem of snakebite and therefore, these issues are also highlighted here. Further, this review suggests a roadmap and guidelines for the prevention of snakebite and improvement of hospital management of snakebite in these Southern Asian countries.

White paper on venomous snakebite in India

Venomous snakebite is one of the leading preventable causes of mortality and morbidity with tremendous socio-economic impact on the family and nation. Venomous snakebite has been relisted as a neglected tropical disease after having been removed off the list in 2013. This paper discusses the various reasons which could be attributed to the high mortality and morbidity due to venomous snakes and also provides recommendations on policy decisions, improvement on the quality of venom and anti-snake venom and in promoting awareness on how to avoid snakebite.

Estimating epidemiological and economic burden and community derived disability weights for snake bite in Kerala: a study protocol

Background: In India, geographical variation, lack of data and underreporting on cases and deaths due to snakebite makes it difficult to estimate socio-economic burden of snakebites. Previous studies measuring economic burden of snakebite in low-and-middle-income countries (LMICs) using different approaches have been conducted, but none so far in India. The proposed study aims to provide evidence on disability weights, epidemiological and economic burden due to snakebites in Kerala state, India. Protocol: A cross-sectional community based study for estimating epidemiological and economic burden of snakebite, recruiting victims of snakebite occurring over a nine month period prior to start and over the three month period of the study, across Ernakulam district, Kerala state, India. For the community derived disability weights, 60 adult patients admitted and treated at Amrita Institute of Medical Sciences, Kochi or Little Flower Hospital, Angamaly would be interviewed. The sample size to determine the mortality rate is calculated at 108,458 persons in Ernakulam.The study will measure annual incidence, mortality, treatment cost of snakebites along with community-derived disability weights for snakebites. Standard methods for analysis and reporting of mortality, morbidity, years of lives lost, years lived with disability, disability weights, and costs of treatment will be calculated and presented. The study will be started in March 2021 and is expected to be completed by June 2021. Discussion: This protocol is the first published for estimating epidemiological, economic burden and community derived disability weights for snakebites in India. Besides, the Global Burden of Disease has not attached a particular disability weight to snakebite and this would be an attempt to do so.The protocol has been developed using guidelines for both cross-sectional studies and  for conducting community derived disability weights. The evidence generated will contribute to knowledge regarding epidemiology, economic burden and community-derived disability weights for snakebites in India and other LMICs.

Estimating epidemiological and economic burden and community derived disability weights for snake bite in Kerala: a study protocol

Background: In India, lack of data and underreporting of cases and deaths due to snakebite makes it difficult to estimate its socio-economic burden. Previous studies measuring economic burden of snakebite in low-and-middle-income countries (LMICs) using different approaches have been conducted, but none  in India. The proposed study aims to provide evidence on disability weights, epidemiological and economic burden due to snakebites in Kerala state, India. Protocol: The study is a community based cross-sectional study recruiting victims of snakebite occurring over a 12 month period prior to start of the study , across  Ernakulam district, Kerala state, India. For the community-derived disability weights,70 adult patients who were treated within a 3 month period prior to commencement of the study at Amrita Institute of Medical Sciences, Kochi or Little Flower Hospital, Angamaly would be interviewed. The study will measure annual incidence, mortality, treatment cost of snakebites along with community-derived disability weights for snakebites in Ernakulam district.. Standard methods for analysis and reporting of mortality, morbidity, Years of Lives Lost (YLL), Years lived with disability (YLD), disability weights, and costs of treatment will be calculated. The study will be started in April 2021 and is expected to be completed by July2021.. Discussion: This protocol is the first published for estimating epidemiological, economic burden and community derived disability weights for snakebites in India. Besides, the Global Burden of Disease has not attached a particular disability weight to snakebite and this would be an attempt to do so. The protocol has been developed using guidelines for cross-sectional studies, cost of illness studies and international guidelines for conducting community derived disability weights. The evidence generated by this study will contribute significantly to knowledge regarding the epidemiology, economic burden and community-derived disability weights for snakebites in India and other countries where incidence of snakebite is high.

Ambispective study of clinical picture, management practices and outcome of snake bite patients at tertiary care centre in Northern India

Background

Snakebite is a common but neglected public health problem of tropical & subtropical regions worldwide. This study was conducted to look into profile, first aid measures, management strategy and outcomes of snake bite patients.

Methods

This was an ambispective study conducted in the Department of Medicine & Emergency Medicine at AIIMS, New Delhi from June 2011 to May 2017 and enrolled 54 patients. In retrospective part 33 case records of snake bite patients were retrieved and in prospective part 21 patients were recruited. All relevant information including demographic parameters, first aid measures, clinical and laboratory profile and outcomes were recorded in pre made proformas. All data were analysed using IBM Stata version 13 and Microsoft Excel 2011.

Results

Majority of patients were male, and the mean age was 27.6 years. Maximum numbers of bites 34 (63%) happened in the rainy season and Krait was the most common culprit species. Neurological manifestations were most common (70.4%) followed by haematological. Most common complication was ventilatory failure (78.6%), and median dose of ASV was 20 vials. Forty-nine (90.7%) patients were discharged successfully. There was significant association of sepsis and shock with non survivors of snake bite with respective P values of 0.02 and 0.007.

Conclusion

Neurotoxic snake bite (70.4%) was the most common type of envenomation. Most common complication was ventilatory failure and majority of patient (90.7%) successfully discharged. Sepsis and shock were significantly associated with non survivors of snake bite.

Global injury morbidity and mortality from 1990 to 2017: results from the Global Burden of Disease Study 2017

BACKGROUND

Past research in population health trends has shown that injuries form a substantial burden of population health loss. Regular updates to injury burden assessments are critical. We report Global Burden of Disease (GBD) 2017 Study estimates on morbidity and mortality for all injuries.

METHODS

We reviewed results for injuries from the GBD 2017 study. GBD 2017 measured injury-specific mortality and years of life lost (YLLs) using the Cause of Death Ensemble model. To measure non-fatal injuries, GBD 2017 modelled injury-specific incidence and converted this to prevalence and years lived with disability (YLDs). YLLs and YLDs were summed to calculate disability-adjusted life years (DALYs).

FINDINGS

In 1990, there were 4 260 493 (4 085 700 to 4 396 138) injury deaths, which increased to 4 484 722 (4 332 010 to 4 585 554) deaths in 2017, while age-standardised mortality decreased from 1079 (1073 to 1086) to 738 (730 to 745) per 100 000. In 1990, there were 354 064 302 (95% uncertainty interval: 338 174 876 to 371 610 802) new cases of injury globally, which increased to 520 710 288 (493 430 247 to 547 988 635) new cases in 2017. During this time, age-standardised incidence decreased non-significantly from 6824 (6534 to 7147) to 6763 (6412 to 7118) per 100 000. Between 1990 and 2017, age-standardised DALYs decreased from 4947 (4655 to 5233) per 100 000 to 3267 (3058 to 3505).

INTERPRETATION

Injuries are an important cause of health loss globally, though mortality has declined between 1990 and 2017. Future research in injury burden should focus on prevention in high-burden populations, improving data collection and ensuring access to medical care.

Perspective on the Therapeutics of Anti-Snake Venom

Snakebite envenomation is a life-threatening disease that was recently re-included as a neglected tropical disease (NTD), affecting millions of people in tropical and subtropical areas of the world. Improvement in the therapeutic approaches to envenomation is required to palliate the morbidity and mortality effects of this NTD. The specific therapeutic treatment for this NTD uses snake antivenom immunoglobulins. Unfortunately, access to these vital drugs is limited, principally due to their cost. Different ethnic groups in the affected regions have achieved notable success in treatment for centuries using natural sources, especially plants, to mitigate the effects of snake envenomation. The ethnopharmacological approach is essential to identify the potential metabolites or derivatives needed to treat this important NTD. Here, the authors describe specific therapeutic snakebite envenomation treatments and conduct a review on different strategies to identify the potential agents that can mitigate the effects of the venoms. The study also covers an increased number of literature reports on the ability of natural sources, particularly plants, to treat snakebites, along with their mechanisms, drawbacks and future perspectives.

Comparing community and hospital data of snakebite in North Bihar: a community incidence survey and a parallel hospital-based clinical study

In Bihar, an estimated 4500 snakebite deaths occur per year, but community data are scarce. Using a multi-stage cluster design, 4159 households were interviewed across six Community Development (CD) blocks in North Bihar, identifying 206 snakebites and 254 deaths between the Chhaat festivals of 2014 and 2015. Concurrently, 357 snakebite victims presented to Duncan Hospital from this area. None of the 254 verbal autopsies were attributed to snakebite envenoming. The annual community snakebite incidence was 643/100,000 person-years (95% confidence interval [CI] = 556-730) with peak incidence in women aged 30-39 years at 1323/100,000 person-years (95% CI = 837-1809). Two-thirds of snakebite victims attended traditional healers first for help (95% CI = 59.9-73.2). The community envenomation rate was 24.9/100,000 person-years (95% CI = 7.6-42.2). The hospital envenomation rate was 4.6% (95% CI = 3.5-5.7). Of the hospital snakebite deaths, 91% (10/11) were aged <16 years. Only 4.6% (95% CI = 4.1-5.1) of snakebite victims from this area presented at the local hospital.

Developing Small Molecule Therapeutics for the Initial and Adjunctive Treatment of Snakebite

The World Health Organization (WHO) recently added snakebite envenoming to the priority list of Neglected Tropical Diseases (NTD). It is thought that ~75% of mortality following snakebite occurs outside the hospital setting, making the temporal gap between a bite and antivenom administration a major therapeutic challenge. Small molecule therapeutics (SMTs) have been proposed as potential prereferral treatments for snakebite to help address this gap. Herein, we discuss the characteristics, potential uses, and development of SMTs as potential treatments for snakebite envenomation. We focus on SMTs that are secretory phospholipase A2 (sPLA2) inhibitors with brief exploration of other potential drug targets on venom molecules.