Clinico-Epidemiological Profile, Trends, and Health-Related Outcomes of Snakebite Victims: A One-Year Prospective Study from Eastern India

INTRODUCTION

Snakebite envenomation is a significant life-threatening public health problem in Southeast Asia (SEA). In this region, India reported the largest number of snakebite deaths from 2000 to 2019 (1.2 million), with an average of 58,000 deaths yearly.

METHODS

This prospective observational study was carried out among snakebite victims at the emergency department (ED) of a tertiary care public sector hospital in eastern India.

RESULTS

A total of 145 cases of venomous snakebite were investigated. More than half (n = 81, 56%) of the snakebite victims were between 17 to 45 years. Most of the snakebite victims were male (68%) and were farmers (53%) by occupation. The majority of snakebites occurred during the daytime (76%) and while outdoors (67%). Most victims sustained a bite on the lower extremity (71%). The peak incidence of snakebites occurred from June to September (69%). Three-quarters of all patients were unaware of the required first aid measures following a snakebite. Among the 145 venomous snakebites, 48 were presumptively identified as the Indian cobra, 32 by the Indian krait, 56 by the Russel's viper, and 9 by saw-scaled viper. The mean duration from the snakebite to the onset of systemic effects in the Indian cobra was 52 ± 14.28 min, 66 ± 18.35 min in the Indian krait, 42 ± 13.47 min in Russel's viper, and 48 ± 16.38 min in saw-scaled viper. Respiratory failure was the commonly observed complication following an elapid envenomation. The mortality rate was 2.1% among the patients treated with antivenom.

CONCLUSIONS

Snakebite is considered an occupational hazard in India, commonly affecting the young population in their productive period. The peak incidence was during monsoon season, and the majority had neurotoxic envenomation following an elapid bite (55%) that contributed to the increased mortality and morbidity among young adults. Of the 145 patients, the majority (84%) recovered fully with treatment; 16% of the victims developed morbidity viz cellulitis, respiratory failure, acute renal failure, compartment syndrome, local tissue necrosis, intracerebral hemorrhage, and disseminated intravascular coagulation. Appropriate first aid measures and timely medical intervention can significantly improve the treatment outcome following snakebites.

Clinical characteristics of snakebite patients attending a tertiary hospital in Hangzhou, southeast China

BACKGROUND

Venomous snakebite is a neglected yet an important public health problem in China, and few studies have focused on them so far. The aim of this study is to investigate clinical characteristics of snakebites patients in a tertiary hospital in Hangzhou, southeast China.

METHODS

A total of 416 snakebite cases were included in this retrospective study. The data were collected from the medical records including demographics, clinical manifestations, management and outcomes.

RESULTS

Of the 416 patients with venomous snakebites, 248 were male, and the average age was 54.6 years. The majority of cases occurred in rural in May to September. Out of all the venomous bites, Gloydius brevicaudus accounted for the highest percentage (55.3%). Hands were the most vulnerable site to snakebites (47.4%). Patients had clinical manifestations of pain (100%), swelling (100%), wound necrosis (25.7%), hemorrhagic blister (18.3%), and blister (8.7%). Three hundred and ninety-two patients received antivenom administration, and most were treated within six hours after bites. Twenty-six patients received surgical treatments, and 90 patients developed venom-induced consumption coagulopathy. No deaths have occurred in this study.

CONCLUSION

Hangzhou is one of the regions with high affecting of snakebites in China. The results of this study will increase the understanding of the clinical characteristics of venomous snakebites in Hangzhou area.

Lack of controlled studies on snakebite prevention: a rapid review

Globally, snakebites cause an estimated 80 000-140 000 deaths annually. While there are evidence-based recommendations for managing snakebite victims, recommendations on the prevention of snakebites are limited to expert opinions. We conducted a rapid review to summarise evidence from human studies with a control group on preventing snakebites. Searching PubMed, Web of Science, Scopus, CINAHL and EMBASE with inclusive search terms without language or time limits only yielded three eligible studies (one case control study and two prospective controlled clinical studies), highlighting a knowledge gap. Two studies in Nepal by the same group showed that health education of stakeholders and sleeping under a bednet can significantly reduce snakebite incidence (p<0.05), but these observations are not confirmed elsewhere, and because of the high risk of bias the certainty of evidence was low. The third study from Sri Lanka, which assessed if sleeping above ground would prevent snakebites, had inconclusive results. This demonstrates an urgent need for studies with a control group to guide evidence-based recommendations for snakebite prevention. Potential interventions tested can range from low-cost measures such as wearing appropriate footwear in resource-limited settings to testing the efficacy of chemical, biological (e.g. rodent control) or device-based methods and community-supported platforms tracking snakebite sightings with real-time geolocation data in highly resourced settings.

Envenomation by Eyelash Viper Bothriechis schlegelii (Berthold, 1846) in Southwestern Colombia

INTRODUCTION

Bothriechis schlegelii is a Crotaline viperid species of Central America and Northern South America. The characteristics of its envenomation have not been well established. We present clinical characteristics of human cases evaluated and treated in a hospital in southwestern Colombia.

METHODS

We evaluated data from patients who suffered Bothriechis schlegelii envenomation and were seen at Fundación Valle del Lili Hospital, Cali, Colombia between 2011 and 2022.

RESULTS

Eight patients were included, with a median age of 24 years. Snakebites occurred in rural areas. Six (75%) patients were bitten on the upper extremities in relation to the arboreal habits of this animal. The most common symptoms were pain and edema (N = 8, 100%), ecchymoses (N = 2, 25%), and paresthesia (N = 2, 25%). The most common systemic findings were hypofibrinogenemia (N = 8, 100%) and prolonged prothrombin time in five patients (N = 5, 62.5%). All were treated with polyvalent antivenom for Colombian snakes, with a good response and outcome.

CONCLUSIONS

Most bite sites from B. schlegelii were on the upper limbs. All patients had both local manifestations, including edema, pain, and systemic effects with hypofibrinogenemia, but none had systemic bleeding. Every patient received antivenom and had favorable outcomes.

Serial envenomation in a snake handler with severe coaguloapathy

We present a rare case study of a 37-year-old man with a history of multiple prior snake bites who presented to the emergency department for treatment of a rattlesnake bite to his right hand. Upon examination, he was found to be mildly hypertensive and exhibited significant coagulation abnormalities. Initial treatment included six vials of Crotalidae polyvalent immune fab; however, his coagulopathy was so severe that he required an additional eight vials. Continuous monitoring and calculations of Snakebite Severity Score demonstrated resolution of coagulopathy within 36 hours of admission. We believe the patient's unusual recovery was likely due to an innate immune response, specifically an activated memory B-cell cascade. This case should lead researchers to consider that the resolution of severe coagulopathy might result from a memory-driven immune response in instances of multiple envenomations.

Current Status and Influencing Factors of Snakebite Diagnosis and Treatment Knowledge Among Medical Staff in China: A Cross-Sectional Study

Objectives: This study aimed to determine the current status of the knowledge of diagnosis and treatment of snakebites among medical staff in China and its influencing factors. Methods: A cross-sectional survey of 12,581 medical staff was conducted in 12 provinces in China between June 2022 and February 2023. We analyzed the results using descriptive statistics, T-tests or analysis of variance, and a generalized linear model. Results: The average score of snakebite diagnosis and treatment knowledge among medical staff in China was 3.15 ± 2.15 out of a total score of 12. Through a generalized linear regression model, we found that gender, occupation, region, hospital level, work department, work tenure, training received in the diagnosis and treatment of snakebite, experience in snakebite diagnosis and treatment, availability of antivenom in the unit, and self-evaluation of snakebite treatment ability all affected the medical staff's scores of snakebite diagnosis and treatment knowledge. Conclusion: The knowledge level of snakebite diagnosis and treatment among Chinese medical staff is generally low, so it is imperative to conduct standardized snakebite diagnosis and treatment training for medical staff.

A Case of Cobra Bite in a Term Pregnant Woman: The Obstetric and Wound Management Challenges

Snake envenomation is a rare incident during pregnancy and potentially challenging to manage. Snakebites in pregnancy may lead to several complications such as teratogenicity, miscarriage, antepartum hemorrhage, and even intrauterine fetal death. Here, we report a case of a pregnant woman who presented to our emergency department with signs of systemic envenomation following an Indian cobra bite on her foot, highlighting the key obstetric and wound management challenges. She complained of severe pain at the site of the bite and progressive swelling, abdominal pain, and multiple episodes of vomiting, which started 45 min after the bite. She received 10 vials of polyvalent antivenom from a primary hospital and was then referred to our center. The patient underwent emergency cesarean section and later fasciotomy with free-flap reconstruction at the bitten site due to local tissue necrosis. The case was successfully managed by a multidisciplinary team consisting of an emergency physician, obstetrician, and plastic surgeon, saving 2 lives and the limb of the patient.

ADDovenom: Thermostable Protein-Based ADDomer Nanoparticles as New Therapeutics for Snakebite Envenoming

Snakebite envenoming can be a life-threatening medical emergency that requires prompt medical intervention to neutralise the effects of venom toxins. Each year up to 138,000 people die from snakebites and threefold more victims suffer life-altering disabilities. The current treatment of snakebite relies solely on antivenom-polyclonal antibodies isolated from the plasma of hyperimmunised animals-which is associated with numerous deficiencies. The ADDovenom project seeks to deliver a novel snakebite therapy, through the use of an innovative protein-based scaffold as a next-generation antivenom. The ADDomer is a megadalton-sized, thermostable synthetic nanoparticle derived from the adenovirus penton base protein; it has 60 high-avidity binding sites to neutralise venom toxins. Here, we outline our experimental strategies to achieve this goal using state-of-the-art protein engineering, expression technology and mass spectrometry, as well as in vitro and in vivo venom neutralisation assays. We anticipate that the approaches described here will produce antivenom with unparalleled efficacy, safety and affordability.

Clinical Risk Factors Associated with Poor Outcomes in Snake Envenoming: A Narrative Review

Snakebite-related fatalities disproportionately affect populations in impoverished socio-economic regions, marked by limited access to adequate healthcare and constrained antivenom availability. Early medical intervention is pivotal in mitigating mortality and morbidity associated with snakebite envenoming (SBE). While clinical assessment remains fundamental in treating SBE, this review aims to spotlight objective parameters that could also affect outcomes. Selected studies that identify factors associated with poor outcomes are predominantly region-specific, single-site, and observational, yet collectively reveal similar findings. They consistently report factors such as treatment delays, susceptibility in vulnerable groups such as children and pregnant women, as well as various biochemical and haematological abnormalities. Acute kidney injury (AKI), low platelets, leucocytosis, abnormal coagulation, and elevated creatine kinase (CK) all show an association with poor outcomes. Furthermore, recognising rare and unusual SBE presentations such as adrenal insufficiency, severe hypertension, intracranial haemorrhage, acute angle closure glaucoma, and bowel ischaemia also has a bearing on outcomes. Despite the integration of these parameters into clinical decision tools and guidelines, the validation of this evidence is limited. This review underscores the imperative for high-quality, multi-centre studies aligned with consensus-driven Core Outcome Sets (COS) and Patient-Reported Outcome Measures (PROMS) to validate and strengthen the current evidence.

A Bibliometric Study on Global Snakebite Research Indexed in Web of Science

Objective: To conduct a bibliometric analysis of the global snakebite literature to provide a reference for the future development of snakebite research. Methods: The Web of Science citation analysis tools, VOSviewer and CiteSpace V were used to carry out the bibliometric analysis of the literature and generate visualization maps. Results: The number of publications has increased at a considerably accelerated rate in the past 8 years. Nine distinct cooperation clusters were formed between institutions and countries. Keyword clustering yielded nine well-structured clusters covering two major topics, i.e., snakebite envenoming and antivenom. Burstiness detection revealed eight keywords with strong emergence, including neglected tropical diseases, Elapidae, Viperidae, and Russell's viper, which have sustained popularity up to the present. Conclusion: Current research on snakebites has gradually garnered attention from the academic community. Cooperation papers between nations severely affected by snakebite and those with higher economic status received more attention. The continued exploration of therapeutic mechanisms, the development of antivenoms or alternative medicines, and primary prevention of snakebites to ensure the safety of populations in impoverished regions should be prioritized by international scholars. The epidemiological evidence and the timely translation of research findings should be valued by policymakers.

Serum Cholesterol Concentration on Admission in 415 Dogs Envenomated by Daboia (Vipera) palaestinae as a Marker of Envenomation Severity and Outcome-A Retrospective Study

Daboia (Vipera) palaestinae (Dp), accounts for most envenomations in humans and dogs in Israel. In humans envenomed by Dp, serum cholesterol concentration (sChol) is inversely correlated with envenomation severity. This study examined the utility of sChol upon admission in dogs envenomed by Dp as an envenomation severity and outcome marker. Data upon admission, including sChol, were retrospectively collected from the medical records of dogs with proven Dp envenomation. The study included 415 dogs. The mortality rate was 11%. The heart rate upon admission was higher in non-survivors than in survivors. Signs of bleeding or hematoma and circulatory shock signs were more frequent among non-survivors compared to survivors. sChol, the platelet count, and serum albumin concentration (sAlb) were lower, while serum creatinine concentration was higher among non-survivors. sChol and sAlb were moderately, positively, and significantly correlated. sChol was significantly, negatively, albeit weakly, correlated with the length of hospitalization and the heart rate. sChol was lower in dogs admitted >12 h post-envenomation than in those admitted later. In dogs, sChol upon admission is a potential marker of severity and outcome of Dp envenomation. The platelet count, sAlb, and sCreat might also be potential markers.

Cold Finger: Raynaud Phenomenon Following Snakebite Envenoming by Nikolsky's Viper (Vipera berus nikolskii)

A field biologist was bitten by a female Nikolsky's viper (Vipera berus nikolskii) in Kharkiv Oblast, Ukraine. Two months later, the patient began to experience cold-induced vasospasm of the affected digit diagnosed as acquired Raynaud phenomenon. The patient had more than 30 occurrences during the single winter following the bite, but the signs and symptoms of Raynaud phenomenon disappeared with the end of winter. This report describes the case and puts it into context with the literature on the topic of toxin-induced peripheral vasospastic disorders and their potential importance in snakebite envenoming.

A Case of Cobra Bite Complicated with Basilar Artery Occlusion

Snakebite is one of the most common complaints related to wilderness medicine. Venomous snakebite manifestation is divided into local and systemic envenomation. For the Elapidae group, the most feared complication is respiratory muscle paralysis due to neurotransmitter malfunction at the neuromuscular junction level which leads to respiratory insufficiency. However, there is a lack of evidence or case report incidence to suggest that it can potentially associate with the development of stroke disorder. We present a rare case of massive posterior circulation infarct in a middle-aged gentleman following a cobra bite. He was brought to our center few hours later following the bite and antivenom was administered. He improved shortly after receiving it. However, he had an abrupt drop in his conscious level several hours later. Noncontrast-enhanced computed tomography (NCCT) brain was performed immediately, but stroke disorder was excluded prematurely. Repeated NCCT imaging which was done 12 h apart showed massive posterior circulation infarction with hydrocephalus. He succumbed to death 3 days later. Given its rarity, the evolution of his clinical condition warrants clinician's early suspicion of potential stroke-related complications that can occur following a cobra bite.

Role of a Plastic Surgeon in the Management of Local Manifestations of Snakebite in a Tertiary Care Hospital: A Prospective Single-Center Case Series

Background  There is a paucity of literature regarding the management of snakebite site complications. The wound complications can have debilitating sequelae, most of which may require reconstruction. Methods  This is a prospective single-institution observational study conducted from November 2019 to December 2021. Patient demographic characteristics and snakebite-related information, length of hospitalization, surgical lesions encountered, the type of treatment offered, and complications were recorded. Results  Fifteen patients (10 males and 5 females) with ages ranging from 10 to 53 years (mean: 36.5 years) were included in the study. Urgent fasciotomy was performed in three patients with compartment syndrome of the upper limb. Facial reconstruction was performed in one patient. One patient required distraction, cross-finger flap, and bone grafting of the index finger, while another patient required a pedicled groin flap for digital salvage. Below knee amputation was done for Marjolin's ulcer in a chronic snakebite case. Few patients required skin grafting. No major complications were encountered. Conclusions  Plastic surgeons play an important role in the management of bite site effects for restoration of form and function, which goes a long way in rehabilitating these patients back in the society. This case series presents a varied range of bite site complications and their management that would serve as a guide to plastic surgeons for better outcome.

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.

Analytical Size Exclusion Chromatography Coupled with Mass Spectrometry in Parallel with High-Throughput Venomics and Bioassaying for Venom Profiling

Modern analytical size exclusion chromatography (SEC) is a suitable technique to separate venom toxin families according to their size characteristics. In this study, a method was developed to separate intact venom toxins from Bungarus multicinctus and Daboia russelii venoms via analytical SEC using volatile, non-salt-containing eluents for post-column mass spectrometry, coagulation bioassaying and high-throughput venomics. Two venoms were used to demonstrate the method developed. While the venom of Bungaurs multicinctus is known to exert anticoagulant effects on plasma, in this study, we showed the existence of both procoagulant toxins and anticoagulant toxins. For Daboia russelii venom, the method revealed characteristic procoagulant effects, with a 90 kDa mass toxin detected and matched with the Factor X-activating procoagulant heterotrimeric glycoprotein named RVV-X. The strong procoagulant effects for this toxin show that it was most likely eluted from size exclusion chromatography non-denatured. In conclusion, the separation of snake venom by size gave the opportunity to separate some specific toxin families from each other non-denatured, test these for functional bioactivities, detect the eluting mass on-line via mass spectrometry and identify the eluted toxins using high-throughput venomics.

Delayed Compression Paralysis Following an Iliopsoas Hematoma 30 Days After Saw-Scaled Viper (Echis carinatus sochureki) Envenoming: A Case Report

Snakebite envenoming is a neglected tropical disease disproportionately affecting the rural and marginalized population in low-middle-income countries. The saw-scaled viper (Echis carinatus) is a clinically important snake that causes serious morbidity and mortality in the Indian subcontinent. Even though it is within the so-called big-four snakes against which polyvalent antivenom is available throughout India, reports of antivenom ineffectiveness are emerging in saw-scaled viper envenoming, especially around Jodhpur, Rajasthan, India. This case report highlights a patient with saw-scaled viper envenoming with an ineffective antivenom response complicated by acute kidney injury as well as local and systemic bleeding complications, which subsequently resulted in a pelvic hematoma that compressed the lumbosacral nerves, causing lower-limb weakness and sensory deficits. He was successfully managed with hematoma aspiration and supportive care. This case brings into focus the challenges of managing saw-scaled viper envenoming in this region with antivenom ineffectiveness, resulting in delayed and significant coagulopathy and its complications leading to prolonged hospital stay and morbidity. Our report spotlights less emphasized aspects of long-term morbidity in snakebite survivors, such as loss of working days and productivity. We also highlight the need for an organized system of long-term follow-up of snakebite survivors to screen for possible complications and manage them early.

Study of pattern and outcome of acute poisoning cases at tertiary care hospital in North India

Introduction

The WHO 2021 data estimate that 2 million lives and 53 million disability-adjusted life-years were lost in 2019 due to exposures to selected chemicals. It is important to know the pattern and outcome of acute poisoning cases for proper planning, prevention and management. Knowing the pattern will also help in designing training modules for primary care physicians to make them aware about newer poisons and their management. Awareness regarding newer poisons consumed is necessary for early identification, initial management and timely referral to higher centres by primary care physicians. This study was performed to see the pattern and outcome of acute poisoning cases in North Indian population and various factors related to outcome.

Materials and Methods

This study was conducted in department of medicine of a teaching institute in North India after approval by the Institutional Review Board. Patients admitted in the department during the study and fulfilling the inclusion criteria were enrolled in the study after obtaining consent.

Results

A total of 417 patients with poisoning were recruited in the study. Out of 417 patients, majority were males (59.5%). Maximum number of patients were in the age group of 21-30 years (33.8%), and rural population (79.9%) was found to be more affected. Most of the patients were students and private employees. Most common types of poisoning were snakebite (n = 109, 26.1%), organophosphate (n = 49, 11.8%) and aluminium phosphide (n = 39, 9.3%). Out of 417 patients, 349 (83.69%) improved, while 68 (16.3%) expired. Requirement of ventilatory support was most commonly associated with aluminium phosphide poisoning (30.12%) followed by organophosphate poisoning (24.1%).

Conclusion

Poisoning was more common in young males and more prevalent in rural population. Pesticides and snakebite were major causes of poisoning. Among suicidal cases, family conflict (problem/altercation with family members/marital discord) was main reason for the consumption of poison. There is need for creation of poison information centre along with separate toxicological units in tertiary care hospitals.

Factors associated with mortality after snakebite envenoming in children: a scoping review

Snakebite envenoming is an important public health issue in many tropical and subtropical countries, where the burden of morbidity and mortality falls particularly on impoverished rural communities. Children are an especially vulnerable group. This scoping review provides an overview of the extent, type and content of peer-reviewed evidence regarding factors associated with mortality in snakebite-envenomed children. A comprehensive literature search of MEDLINE and the Global Index Medicus yielded 623 articles, of which 15 met the criteria for inclusion; 67% of studies were conducted in India, with the remaining studies taking place in Papua New Guinea, Morocco and The Gambia. There was a notable scarcity of eligible studies from sub-Saharan Africa and Latin America despite the high burden of envenoming in these regions. The risk factors for mortality that were identified by the greatest number of studies were younger patient age (n=4), delay in administration of antivenom (n=4) and acute kidney injury (n=3). Identification of poor prognostic factors can assist clinicians in making timely referrals to centres with paediatric critical care capability. Future research must address the lack of studies from key geographical regions so that evidence-based improvements to the care of this vulnerable group can be implemented.

Venomics of the milos viper (Macrovipera schweizeri) unveils patterns of venom composition and exochemistry across blunt-nosed viper venoms

Introduction: Snakebite is a neglected tropical disease and a globally important driver of death and morbidity. Vipers of the genus Macrovipera (Viperidae: Viperinae) are among the snakes of higher medical importance in the Old World. Despite the medical relevance of Macrovipera venoms, the knowledge regarding them is heterogeneously distributed with virtually all works conducted so far focusing on subspecies of Macrovipera lebetinus, while other species within the genus are largely overlooked. Here we present the first proteomic evaluation of the venom from the Greek endemic Milos viper (Macrovipera schweizeri). In line with clinical symptoms typically elicited by Macrovipera envenomations, Milos viper venom primarily comprises coagulotoxic and cytotoxic protein families, such as metalloproteinases (svMP) and serine proteases (svSP). Methods: We conducted comparative bioactivity assays on venoms from M. schweizeri and the M. lebetinus subspecies M. lebetinus cernovi, M. lebetinus obtusa, and M. lebetinus turanica, and showed that they all exhibit similarities in levels of cytotoxicity proteolytic activity, and inhibition of prokaryotic growth. Lastly, we compared Macrovipera venom profiles by 1D-SDS-PAGE and RP-HPLC, as well as our proteomic data with previously published Macrovipera venom proteomes. Results and discussion: The analyzes performed to reveal that a general venom profile seems to be conserved across blunt-nosed vipers, and that, M. schweizeri envenomations, similarly to those caused by other blunt-nosed vipers, are able to cause significant tissue damage. The present work represents an important starting point for the development of comparative studies across the full taxonomic range of the genus Macrovipera and can potentially help optimize the treatment of envenomations caused by M. schweizeri.

Investigating the Clinical Value of Novel Kidney Injury Inflammatory Biomarkers in Snakebite Victims

OBJECTIVE

The expression of vascular endothelial growth factor-A (VEGF-A) in snakebite patients, its value in patient prognosis and the correlation of VEGF-A with renal function were analysed.

METHODS

A total of 124 snakebite patients admitted from January 2019 to January 2021 were retrospectively analysed and included in the observation group, and 40 healthy individuals who underwent physical examination in the same hospital within the same period were included in the control group. The t-test was used in analysing differences between the serum VEGF-A levels of the observation and control groups and changes in VEGF-A and renal function indices before and after treatment in the observation group. The effects of treatment on each patient in the observation group were evaluated, and the patients were divided into improved and unimproved groups according to the post-treatment condition. The predictive value of VEGF-A and renal function indices in patients in the improved and unimproved groups and their efficacy for snakebite patients were analysed through receiver operating characteristic (ROC) analysis. Finally, correlation analysis was used in evaluating the correlation between VEGF-A and renal function indices.

RESULTS

VEGF-A was significantly higher in patients in the observation group (339.66 ± 97.72 pg/mL) than in patients in the control group (52.41 ± 8.93 pg/mL; p < 0.001). VEGF-A and renal function indices in the serum of patients were significantly lower after treatment than those before treatment (p < 0.0001). According to efficacy, the patients were divided into improved group (n = 102) and unimproved group (n = 22). The pre-treatment VEGF-A levels were significantly lower in patients in the improved group (318.47 ± 90.80 pg/mL) than in patients in the unimproved group (437.88 ± 63.16 pg/mL; p < 0.001). ROC curve analysis revealed that the area under the curve for VEGF-A in predicting patient treatment efficacy was 0.886, and VEGF-A was positively correlated with blood urea nitrogen, creatinine and cystin C but negatively correlated with glomerular filtration rate (p < 0.001).

CONCLUSIONS

VEGF-A was highly expressed in snakebite patients and can be used as an observational indicator for predicting the prognosis of snakebite patients.

Delayed-onset Angioedema Following a Snakebite in a Patient on ACE Inhibitors: A Case Report

INTRODUCTION

Angiotensin converting enzyme inhibitors (ACEI) are a common class of medications prescribed to patients for hypertension. Anti-hypertensive use is not normally considered an important factor when treating patients with crotalid envenomations; however, in combination with the venom in this patient, it may have resulted in angioedema.

CASE REPORT

A 65-year-old male on ACEI presented to his community emergency department following a snake envenomation to his thumb. Six vials of Crotalidae polyvalent immune fab were administered, and he was transferred to a referral center. Approximately 18 hours after the envenomation, the patient complained of tongue swelling and difficulty speaking. There was evidence of angioedema, with the right side of the tongue significantly enlarged compared to the left. He was intubated for airway protection and remained on a ventilator for three days.

CONCLUSION

Angiotensin converting enzyme inhibitors may potentiate the effects of exogenous bradykinin as some snake venom has naturally occurring bradykinin, which may further amplify its effects. Extra vigilance may be warranted for the development of angioedema in patients receiving ACEI.

Incidence of serum sickness following Indian polyvalent antivenom therapy in a cohort of snake-envenomed patients in rural Sri Lanka

INTRODUCTION

Serum sickness is a poorly reported delayed adverse reaction following snake antivenom therapy. We aimed to assess the frequency of serum sickness associated with administering Indian polyvalent antivenom in Sri Lanka.

METHODS

We recruited patients from the Anuradhapura snakebite cohort who were admitted to a rural tertiary care hospital in Sri Lanka over one year period. Patients were interviewed over the phone 21 to 28 days post-envenoming to collect data on clinical effects: fever/chills, arthralgia/myalgia, rash, malaise, headache, abdominal pain, and nausea/vomiting. The presence of three or more symptoms between the 5th to 20th days after snake envenoming was defined as serum sickness.

RESULTS

We were able to contact 98/122 (80%) patients who received antivenom and 423/588 (72%) who did not receive antivenom during the study period. The treated patients received a median dose of 20 vials (interquartile range: 20-30) of Indian polyvalent antivenom and of them, 92 (92%) received premedication. However, 67/98 (68%) developed acute adverse reactions to antivenom, including 19/98 (19%) developing anaphylaxis. Only 4/98 (4%) who received antivenom met the criteria for serum sickness, compared to none who did not receive antivenom therapy. All patients who developed serum sickness were envenomed by Russell's vipers, were premedicated, and received VINS Bioproducts antivenom. Three of them were treated with hydrocortisone in the acute stage, as premedication or as a treatment for acute adverse reactions of antivenom. Although all four patients sought medical advice for their symptoms, only one was clinically suspected to be serum sickness and treated, while the others were treated for infections.

CONCLUSIONS

We confirmed that Indian polyvalent antivenom use in Sri Lanka is associated with high rates of acute adverse reactions. In contrast to studies of other antivenoms only a small proportion of patients developed serum sickness.

The Association Between Ambient Temperature and Snakebite in Georgia, USA: A Case-Crossover Study

The World Health Organization has identified snakebite envenoming as a highest priority neglected tropical disease, yet there is a dearth of epidemiologic research on environmental risk factors, including outdoor temperature. Temperature may affect snakebites through human behavior or snake behavior; snakes are ectotherms, meaning outdoor temperatures influence their internal body temperature and thus their behavior. Here we investigate the relationship between short-term temperature and snakebites in Georgia, one of the most biodiverse US states in terms of herpetofauna. We acquired emergency department (ED) visit data for Georgia between 1 January 2014 and 31 December 2020. Visits for venomous and non-venomous snakebites were identified using diagnosis codes. For comparison, we also considered visits for non-snake (e.g., insects, spiders, scorpions) envenomation. Daily meteorology from the Daymet 1 km product was linked to patient residential ZIP codes. We applied a case-crossover design to estimate associations of daily maximum temperature and snakebite ED visits. During the 7-year study period, there were 3,908 visits for venomous snakebites, 1,124 visits for non-venomous bites and 65,187 visits for non-snake envenomation. Across the entire period, a 1°C increase in same-day maximum temperature was associated with a 5.6% (95%CI: 4.0-7.3) increase in the odds of venomous snakebite and a 5.8% (95%CI: 3.0-8.8) increase in non-venomous snakebite. Associations were strongest in the spring. We also observed a positive and significant (p < 0.05) association for non-snake envenomation, albeit slightly smaller and more consistent across seasons compared to those for snakebites.

Redefining the role of therapeutic plasma exchange in complications of Echis carinatus sochureki envenomation refractory to anti-snake venom: A case series

INTRODUCTION

Saw-scaled viper (Echis carinatus) belongs to the Viperidae family. Its venom is hemotoxic and contains several small peptides and proteins affecting the coagulation system. Commonly used anti-snake venom (ASV) products in India are reported to be ineffective or less effective in cases with bites by Echis carinatus sochureki which are commonly found in desert areas in Rajasthan. Although therapeutic plasma exchange (TPE) has been successful in patients with snakebite envenomation in the past, American Society for Apheresis guidelines 2019 included this indication under category III with grade 2C recommendation.

AIM AND OBJECTIVES

To report the safety and efficacy of therapeutic plasma exchange procedures in the setting of ASV refractory E. c. sochureki envenomation.

MATERIALS AND METHODS

Four patients admitted to our institute in 2021 September with an alleged history of snake bites and who underwent at least one cycle of therapeutic plasma exchange were assessed for clinical outcome, laboratory parameters, and blood product consumption.

RESULTS

Three adult patients and one pediatric patient are included in this case series, all of them males. Indication for TPE in one case was suspected diffuse alveolar hemorrhage (DAH), while in all the other cases was thrombotic microangiopathy (TMA). All received a variable number of sessions from 2 to 5 and 1.3-1.5 plasma volume was removed on an average per cycle. The endpoint of TPE was the resolution of DAH in one while a reduction in lactate dehydrogenase and an increase in platelet count was in TMA cases. Consumption of blood products was drastically reduced in all four patients after starting the procedure. All the adult patients fared well on follow-up while the child had developed acute cortical necrosis and was dialysis-dependent. It has been noted in the previous studies too that a subset of snakebite-induced TMA cases was getting converted to chronic kidney disease and becoming dialysis dependent in the long run.

CONCLUSIONS

In regions where ASV treatment failure is very common, therapeutic plasma exchange is a safe and effective complementary treatment modality along with supportive care.

Snake Antivenoms-Toward Better Understanding of the Administration Route

Envenomations induced by animal bites and stings constitute a significant public health burden. Even though a standardized protocol does not exist, parenterally administered polyclonal antivenoms remain the mainstay in snakebite therapy. There is a prevailing opinion that their application by the i.m. route has poor efficacy and that i.v. administration should preferentially be chosen in order to achieve better accomplishment of the antivenom therapeutic activity. Recently, it has been demonstrated that neutralization not only in the systemic circulation but also in the lymphatic system might be of great importance for the clinical outcome since it represents another relevant body compartment through which the absorption of the venom components occurs. In this review, the present-day and summarized knowledge of the laboratory and clinical findings on the i.v. and i.m. routes of antivenom administration is provided, with a special emphasis on the contribution of the lymphatic system to the process of venom elimination. Until now, antivenom-mediated neutralization has not yet been discussed in the context of the synergistic action of both blood and lymph. A current viewpoint might help to improve the comprehension of the venom/antivenom pharmacokinetics and the optimal approach for drug application. There is a great need for additional dependable, practical, well-designed studies, as well as more practice-related experience reports. As a result, opportunities for resolving long-standing disputes over choosing one therapeutic principle over another might be created, improving the safety and effectiveness of snakebite management.

Snakebite-associated thrombotic microangiopathy: a spotlight on pharmaceutical interventions

INTRODUCTION

Snakebite is a neglected public health issue causing death and disability, disproportionately affecting tropical and subtropical resource poor countries globally. Snakebite-associated thrombotic microangiopathy (TMA) occurs in a subset of snakebites and is associated with acute kidney injury (sometimes requiring renal replacement therapy), and a risk of chronic kidney disease.

AREAS COVERED

This expert review synthesizes current evidence on therapeutic interventions in snakebite-associated TMA, via PubMed search for cohort studies and randomized controlled trials (RCT) in snakebite-associated TMA from 1970 to October 2022.

EXPERT OPINION

There are no interventional RCTs in snakebite-associated TMA. Recent cohort studies from Sri Lanka, India and Australia report clinical and laboratory endpoint outcomes for intervention with antivenom and therapeutic plasma-exchange (TPE). TPE is a resource intense and costly treatment using large volumes of blood donor plasma. There is no consistent evidence supporting TPE in snakebite-associated TMA with respect to patient survival, dialysis free survival, or hospital length of stay. Antivenom is the standard of care for patients with snake envenoming, but there is no specific evidence of benefit in snakebite-associated TMA. Emerging new therapies in snakebite more broadly are untested in snakebite-associated TMA. RCTs are needed to improve the evidence for treatment of snakebite-associated TMA.

Monitoring Snake Venom-Induced Extracellular Matrix Degradation and Identifying Proteolytically Active Venom Toxins Using Fluorescently Labeled Substrates

Snakebite envenoming is an important public health issue with devastating consequences and annual mortality rates that range between 81,000 and 138,000. Snake venoms may cause a range of pathophysiological effects affecting the nervous system and the cardiovascular system. Moreover, snake venom may have tissue-damaging activities that result in lifelong morbidities such as amputations, muscle degeneration, and organ malfunctioning. The tissue-damaging components in snake venoms comprise multiple toxin classes with various molecular targets including cellular membranes and the extracellular matrix (ECM). In this study, we present multiple assay formats that enable investigation of snake venom-induced ECM degradation using a variety of (dye-quenched) fluorescently labeled ECM components. Using a combinatorial approach, we were able to characterise different proteolytic profiles for different medically relevant snake venoms, followed by identification of the responsible components within the snake venoms. This workflow could provide valuable insights into the key mechanisms by which proteolytic venom components exert their effects and could therefore prove useful for the development of effective snakebite treatments against this severe pathology.

Venomous Bites, Stings and Poisoning by European Vertebrates as an Overlooked and Emerging Medical Problem: Recognition, Clinical Aspects and Therapeutic Management

Europe presents a high number of venomous and poisonous animals able to elicit medically relevant symptoms in humans. However, since most of the accidents involving venomous or poisonous animals in Europe are unreported, their incidence and morbidity are severely overlooked. Here we provide an overview of the European vertebrate species of greatest toxicological interest, the clinical manifestations their toxins can cause, and their treatment. We report the clinical symptoms induced by envenomations and poisoning caused by reptiles, fishes, amphibians and mammals in Europe, ranging from mild, local symptoms (e.g., erythema, edema) to systemic and potentially deadly. The present work constitutes a tool for physicians to recognize envenomation/poisoning symptoms caused by the most medically relevant European vertebrates and to decide which approach is the most appropriate to treat them.

Application of Sonographic Assessments of the Rate of Proximal Progression to Monitor Protobothrops mucrosquamatus Bite-Related Local Envenomation: A Prospective Observational Study

Patients bitten by Protobothrops mucrosquamatus typically experience significant pain, substantial swelling, and potentially blister formation. The appropriate dosage and efficacy of FHAV for alleviating local tissue injury remain uncertain. Between 2017 and 2022, 29 snakebite patients were identified as being bitten by P. mucrosquamatus. These patients underwent point-of-care ultrasound (POCUS) assessments at hourly intervals to measure the extent of edema and evaluate the rate of proximal progression (RPP, cm/hour). Based on Blaylock's classification, seven patients (24%) were classified as Group I (minimal), while 22 (76%) were classified as Group II (mild to severe). In comparison to Group I patients, Group II patients received more FHAV (median of 9.5 vials vs. two vials, p-value < 0.0001) and experienced longer median complete remission times (10 days vs. 2 days, p-value < 0.001). We divided the Group II patients into two subgroups based on their clinical management. Clinicians opted not to administer antivenom treatment to patients in Group IIA if their RPP decelerated. In contrast, for patients in Group IIB, clinicians increased the volume of antivenom in the hope of reducing the severity of swelling or blister formation. Patients in Group IIB received a significantly higher median volume of antivenom (12 vials vs. six vials; p-value < 0.001) than those in Group IIA. However, there was no significant difference in outcomes (disposition, wound necrosis, and complete remission times) between subgroups IIA and IIB. Our study found that FHAV does not appear to prevent local tissue injuries, such as swelling progression and blister formation, immediately after administration. When administering FHAV to patients bitten by P. mucrosquamatus, the deceleration of RPP may serve as an objective parameter to help clinicians decide whether to withhold FHAV administration.

Application of an Extracellular Matrix-Mimicking Fluorescent Polymer for the Detection of Proteolytic Venom Toxins

The cytotoxicity caused by snake venoms is a serious medical problem that greatly contributes to the morbidity observed in snakebite patients. The cytotoxic components found in snake venoms belong to a variety of toxin classes and may cause cytotoxic effects by targeting a range of molecular structures, including cellular membranes, the extracellular matrix (ECM) and the cytoskeleton. Here, we present a high-throughput assay (384-well plate) that monitors ECM degradation by snake venom toxins via the application of fluorescent versions of model ECM substrates, specifically gelatin and collagen type I. Both crude venoms and fractionated toxins of a selection of medically relevant viperid and elapid species, separated via size-exclusion chromatography, were studied using the self-quenching, fluorescently labelled ECM-polymer substrates. The viperid venoms showed significantly higher proteolytic degradation when compared to elapid venoms, although the venoms with higher snake venom metalloproteinase content did not necessarily exhibit stronger substrate degradation than those with a lower one. Gelatin was generally more readily cleaved than collagen type I. In the viperid venoms, which were subjected to fractionation by SEC, two (B. jararaca and C. rhodostoma, respectively) or three (E. ocellatus) active proteases were identified. Therefore, the assay allows the study of proteolytic activity towards the ECM in vitro for crude and fractionated venoms.

Captive Black Mamba (Dendroaspis Polylepis) Bite Leading to Respiratory Failure

BACKGROUND

Of the 8000-10,000 snake envenomations evaluated in U.S. emergency departments (ED) annually, approximately 1% are due to non-native snakes. We describe a 26-year-old man who was bitten by his captive black mamba (Dendroaspis polylepis) as he was packing it up for transport to another snake collector.

CASE REPORT

The patient presented to the ED 1 h after being bitten on the forearm, complaining of left arm pain, oral paresthesias, and dyspnea. His vital signs: heart rate 96 beats/min, blood pressure 167/101 mm Hg, temperature 36.7°C (97.9°F), respiratory rate 20 breaths/min, and room air oxygen saturation 100%. Two mildly tender puncture wounds without swelling or ecchymosis were found on the posterior aspect of the forearm. Over the ensuing 30 min his dyspnea worsened, and he developed objective weakness. He was intubated and placed on mechanical ventilation. He was treated with atropine 2 mg for bronchorrhea. Five vials of South African Vaccine Producers (Johannesburg, South Africa) polyvalent antivenom were administered 2.5 h post-bite and the patient was admitted to the intensive care unit. He was extubated 18 h post-envenomation and discharged the following day. He has remained asymptomatic since leaving the hospital. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: The primary manifestations of D. polylepis envenomings are neurological. Initial signs may include paresthesias, dysarthria, dysphagia, and ptosis. Progressive descending paralysis leading to respiratory failure develops within 60 min. Muscarinic features are frequently observed. Cardiotoxicity and hematologic laboratory abnormalities may be present. Although pain is common, significant local tissue injury does not occur. In addition to supportive care, several non-native antivenoms are indicated for D. polylepis envenomations. Black mamba envenomings differ from the native snakebites with which U.S. physicians are familiar. Rapid, progressive neurological toxicity and muscarinic features are most common. Treatment consists of supportive care and appropriate antivenom administration.

Attitudes, knowledge and practices of traditional snakebite healers in Nepal: implications for prevention and control of snakebite

BACKGROUND

Traditional healers are a valuable source of information about community-level treatment of snakebite. Snakebite victims in Nepal depend on traditional healers for treatment, but their practices have not been well-documented.

METHODS

This was a cross-sectional study of 50 traditional snakebite healers (TSHs) who were selected using a snowball sampling method representing eight districts and four provinces of Nepal. Data were collected using face-to-face-interviews and semi-structured questionnaires.

RESULTS

About half of the respondents liked to gain knowledge on modern care for snakebite management and nearly all respondents (94%) wished to cooperate closely with the local healthcare system to support snakebite management. People's ingrained faith in traditional healing of snakebite (84%), unaffordable modern care of snakebite (60%) and wishes for early treatment of snakebites (44-48%) were the main causes of their dependency on TSHs. Rauvolfia serpentina, Piper nigrum, Momordica charantia and Tinospora cordifolia were commonly used plants in traditional treatment of snakebite.

CONCLUSIONS

Easily accessible and affordable healthcare facilities provided by TSHs, public beliefs in traditional healing and inadequate knowledge of antivenom therapy caused dependency on TSHs. The introduction of snakebite treatment centres in snakebite-prone regions and educational interventions are essential to minimize this kind of dependency and associated deaths and disabilities.

Lifetime prevalence and knowledge of snakebite among graduates in Nigeria

BACKGROUND

Given the lack of studies on snakebite envenoming knowledge in the general population, we examined the lifetime prevalence of snakebite and knowledge of snakebite and its prevention and first aid among recent Nigerian graduates in national service.

METHODS

This questionnaire-based cross-sectional study involved 351 consenting national youth corps members at a rural orientation camp in Kano, Nigeria.

RESULTS

Participants' mean age was 25.3±2.4 y. There were slightly more males (50.7%). Most attended universities (77.8%) and were mainly from the southwest (24.5%) and northeast (24.5%) geopolitical regions and the Yoruba tribe (24.7%). Their lifetime prevalence of snakebite was 4%. Their mean overall knowledge score was 6.8±3.1 out of 20. Only 0.9% had adequate knowledge. Gender (male; 7.2±3.1, t=2.83, p=0.0049), tribe (Yoruba; 7.5±2.9, F=2.968, p=0.0320), region (Southwest; 7.6±3.0, F=2.5289, p=0.0289) and nearly bitten by snake (7.8 ± 2.7, t=3.60, p=0.0004) were significantly associated with a higher mean knowledge score.

CONCLUSIONS

Their lifetime prevalence of snakebites is significant, while knowledge of snakebite is very inadequate. However, the national service camp activities period provides an opportunity for educational intervention needed to raise their knowledge to optimal levels that will enable them serve as better snakebite prevention agents, as they will be working in rural communities where snakebite might be prevalent.

Snakebite envenoming in Brazilian children: clinical aspects, management and outcomes

Snakebite envenoming is currently considered a neglected tropical disease, which affects over 5 million people worldwide, and causes almost 150 000 deaths every year, as well as severe injuries, amputations and other sequelae. Snakebite envenoming in children, although proportionally less frequent, is generally more severe, and represents an important challenge for pediatric medicine, since they often result in worse outcomes. In Brazil, given its ecological, geographic and socioeconomic characteristics, snakebites are considered an important health problem, presenting approximately 30 000 victims per year, approximately 15% of them in children. Even with low snakebite incidence, children tend to have higher snakebite severity and complications due to the small body mass and same venom volume inoculated in comparison to adults, even though, due to the lack of epidemiological information about pediatric snakebites and induced injuries, it is difficult to measure the treatment effectiveness, outcomes and quality of emergency medical services for snakebites in children. In this review, we report how Brazilian children are affected by snakebites, describing the characteristics of this affected population, clinical aspects, management, outcomes and main challenges.

Neuromuscular Weakness and Paralysis Produced by Snakebite Envenoming: Mechanisms and Proposed Standards for Clinical Assessment

Respiratory and airway-protective muscle weakness caused by the blockade of neuromuscular transmission is a major cause of early mortality from snakebite envenoming (SBE). Once weakness is manifest, antivenom appears to be of limited effectiveness in improving neuromuscular function. Herein, we review the topic of venom-induced neuromuscular blockade and consider the utility of adopting clinical management methods originally developed for the safe use of neuromuscular blocking agents by anesthesiologists in operating rooms and critical care units. Failure to quantify neuromuscular weakness in SBE is predicted to cause the same significant morbidity that is associated with failure to do so in the context of using a clinical neuromuscular block in surgery and critical care. The quantitative monitoring of a neuromuscular block, and an understanding of its neurophysiological characteristics, enables an objective measurement of weakness that may otherwise be overlooked by traditional clinical examination at the bedside. This is important for the initial assessment and the monitoring of recovery from neurotoxic envenoming. Adopting these methods will also be critical to the conduct of future clinical trials of toxin-inhibiting drugs and antivenoms being tested for the reversal of venom-induced neuromuscular block.

The BRAVO Clinical Study Protocol: Oral Varespladib for Inhibition of Secretory Phospholipase A2 in the Treatment of Snakebite Envenoming

INTRODUCTION

Snakebite is an urgent, unmet global medical need causing significant morbidity and mortality worldwide. Varespladib is a potent inhibitor of venom secretory phospholipase A2 (sPLA2) that can be administered orally via its prodrug, varespladib-methyl. Extensive preclinical data support clinical evaluation of varespladib as a treatment for snakebite envenoming (SBE). The protocol reported here was designed to evaluate varespladib-methyl for SBE from any snake species in multiple geographies.

METHODS AND ANALYSIS

BRAVO (Broad-spectrum Rapid Antidote: Varespladib Oral for snakebite) is a multicenter, randomized, double-blind, placebo-controlled, phase 2 study to evaluate the safety, tolerability, and efficacy of oral varespladib-methyl plus standard of care (SoC) vs. SoC plus placebo in patients presenting with acute SBE by any venomous snake species. Male and female patients 5 years of age and older who meet eligibility criteria will be randomly assigned 1:1 to varespladib-methyl or placebo. The primary outcome is the Snakebite Severity Score (SSS) that has been modified for international use. This composite outcome is based on the sum of the pulmonary, cardiovascular, nervous, hematologic, and renal systems components of the updated SSS.

ETHICS AND DISSEMINATION

This protocol was submitted to regulatory authorities in India and the US. A Clinical Trial No Objection Certificate from the India Central Drugs Standard Control Organisation, Drug Controller General-India, and a Notice to Proceed from the US Food and Drug Administration have been obtained. The study protocol was approved by properly constituted, valid institutional review boards or ethics committees at each study site. This study is being conducted in compliance with the April 1996 ICH Guidance for Industry GCP E6, the Integrated Addendum to ICH E6 (R2) of November 2016, and the applicable regulations of the country in which the study is conducted. The trial is registered on Clinical trials.gov, NCT#04996264 and Clinical Trials Registry-India, 2021/07/045079 000062.

Systematic review and meta-analysis of global prevalence of neurotoxic and hemotoxic snakebite envenomation

Background

The World Health Organization estimates that there are approximately 5.4 million snakebites and 1.8-2.7 million cases of envenomation, with 81 410-137 880 deaths each year worldwide.

Aims

To estimate the prevalence of neurotoxic and haemotoxic snakebite envenomation through a comprehensive systematic review and meta-analysis.

Methods

We searched Medline/PubMed, Scopus and Cochrane Library up to January 2021 using keywords such as snakebite and snake envenomation. Bibliographic and random searches were also performed. Prospective or retrospective observational studies and randomized controlled trials were included for the review.

Results

We included 271 of 9711 studies published between 1963 and 2020. The pooled prevalence of snakebite from 188 studies with a total of 207 235 participants showed the highest prevalence in North America (69.20%; 95% confidence interval, CI: 57.06-81.34%) and lowest in Africa (28.10%; 95% CI: 22.22-33.98%). There was a pooled prevalence of 24.94% (95% CI: 22.84-27.03%) for haemotoxicity, with a highest prevalence of coagulopathy (43.76%; 95% CI: 33.15-54.37%). The overall prevalence of neurotoxicity was 38.20% (95% CI: 31.88-44.53%), with a highest prevalence of ptosis (53.57%; 95% CI: 38.51-68.62%).

Conclusion

There was a higher prevalence of snakebites in North America. The most prevalent haemotoxicity and neurotoxicity were coagulopathy and ptosis, respectively. The overall quality of evidence was good with a non-significant publication bias.

Commercial Antivenoms Exert Broad Paraspecific Immunological Binding and In Vitro Inhibition of Medically Important Bothrops Pit Viper Venoms

Snakebite envenoming is a life threatening neglected tropical disease that represents a considerable public health concern in the tropics. Viperid snakes of the genus Bothrops are among those of greatest medical importance in Latin America, and they frequently cause severe systemic haemotoxicity and local tissue destructive effects in human victims. Although snakebite antivenoms can be effective therapeutics, their efficacy is undermined by venom toxin variation among snake species. In this study we investigated the extent of paraspecific venom cross-reactivity exhibited by three distinct anti-Bothrops antivenoms (Soro antibotrópico-crotálico, BothroFav and PoliVal-ICP) against seven different Bothrops pit viper venoms from across Latin America. We applied a range of in vitro assays to assess the immunological binding and recognition of venom toxins by the antivenoms and their inhibitory activities against specific venom functionalities. Our findings demonstrated that, despite some variations, the monovalent antivenom BothroFav and the polyvalent antivenoms Soro antibotrópico-crotálico and PoliVap-ICP exhibited extensive immunological recognition of the distinct toxins found in the different Bothrops venoms, with Soro antibotrópico-crotálico generally outperformed by the other two products. In vitro functional assays revealed outcomes largely consistent with the immunological binding data, with PoliVap-ICP and BothroFav exhibiting the greatest inhibitory potencies against procoagulant and fibrinogen-depleting venom activities, though Soro antibotrópico-crotálico exhibited potent inhibition of venom metalloproteinase activities. Overall, our findings demonstrate broad levels of antivenom paraspecificity, with in vitro immunological binding and functional inhibition often highly comparable between venoms used to manufacture the antivenoms and those from related species, even in the case of the monovalent antivenom BothroFav. Our findings suggest that the current clinical utility of these antivenoms could possibly be expanded to other parts of Latin America that currently suffer from a lack of specific snakebite therapies.

Green Pit Viper Envenomations in Bangkok: A Comparison of Follow-Up Compliance and Clinical Outcomes in Older and Younger Adults

We compared older and younger adults envenomated by the green pit viper (GPV) with regard to the following: follow-up compliance, elapsed time between envenomation and emergency department (ED) visit, and clinical/treatment outcomes. This was a two-site retrospective cohort study. We searched hospital electronic medical databases between January 2011 and December 2021. Patients aged 15 and above were eligible if they had a history of snakebite and had at least two VCT and/or platelet count results in their medical records. After the search, 1550 medical records were reviewed and 760 cases were found to be eligible for analysis. In total, 205 cases (27.0%) were ≥60 years old. The median ages in the younger and older groups were 40 (26-51) and 68 (64-75) years, respectively. The median elapsed times from bite to the ED were 47 (30-118) vs. 69 (35-150) min (p-value = 0.001). Overall, 91.3% of all cases were managed as out-patient cases and were eligible for follow-up appointments. The rate of out-patient follow-up at 72 ± 12 h in the older patients was significantly higher (43.2%) than in the younger adult patients (32.4%) (p-value = 0.01). Regarding the clinical/treatment outcomes, the rates of coagulopathy, antivenom administration, and hospital admission were not statistically different between both groups.

Comparison of bedside clotting tests for detecting venom-induced consumption coagulopathy following Sri Lankan viper envenoming

BACKGROUND

The whole blood clotting test (WBCT) is commonly used for diagnosing venom-induced consumption coagulopathy (VICC) in resource-poor settings. We aimed to investigate the diagnostic accuracy of the WBCT and capillary blood clotting test (CBCT) for detecting VICC in viper envenoming in Sri Lanka.

METHODS

All confirmed snakebites admitted to Teaching Hospital Anuradhapura from July 2020 to June 2021 were included. On admission, WBCTs after 15, 20 and 25 min observation times (WBCT-15, WBCT-20 and WBCT-25) and CBCT observed in 30 s intervals (CBCT-t), 5 and 10 min CBCT (CBCT-5 and CBCT-10) were done. Blood was collected simultaneously for prothrombin time (PT)/international normalized ratio (INR) and plasma fibrinogen. We defined VICC as an INR >1.5 (Incomplete VICC = INR>1.5 and complete VICC = ≥3.0).

RESULTS

A total of 272 confirmed snakebites (Russell's viper[76], hump-nosed viper[89], non-venomous snakes[51] and unidentified bites[56]) were recruited (median age: 42 y [interquartile range: 30- 53 y]; 189 males [69%]). On admission, 82 (30%) had incomplete VICC (INR >1.5 and <3) and 77 (28%) had complete VICC (INR ≥3). Sixteen (6%) developed clinically apparent bleeding. The WBCT-15 had the best sensitivity of 47% for detecting VICC and 68% for complete VICC. The sensitivities of the WBCT-20, WBCT-25, CBCT-5 and CBCT-10 was 30-35%. The sensitivities of all tests were better in detecting complete VICC, VICC in Russell's viper bites and more than 2 h post-bite. The WBCT-15 test had a sensitivity of 76% for VICC in confirmed Russell's viper bites. For detection of VICC, CBCT-t had an an excellent sensitivity of 97%, but a poor specificity of 35% for an optimal cut-off of >6.25 min.

CONCLUSION

WBCTs are poorly diagnostic for VICC in Russell's viper and hump-nosed viper envenoming, missing up to two-thirds of patients for some tests. The WBCT-15 was the best test, improving for more severe VICC and greater than 2 h post-bite.

Diagnostic Tests for Hypofibrinogenemia Resulting from Green Pit Viper (Trimeresurus albolabris) Envenomation: A Simulated In Vitro Study

INTRODUCTION

The green pit viper (GPV) Trimeresurus albolabris is found in Southeast Asia. Its venom has a thrombin-like activity that can cause hypofibrinogenemia. Fibrinogen measurement is not always available. We aimed to establish a more available diagnostic tool indicating hypofibrinogenemia caused by GPV envenomation.

METHODS

This was an in vitro study, in which healthy subjects aged 20 to 45 y were enrolled. There were 2 experiments. In Experiment 1, blood samples from 1 subject had varying amounts of T albolabris venom added to determine its effect on the fibrinogen level (FL). In Experiment 2, 3 sets of blood samples were obtained from another 25 subjects. The 2 venom doses established in Experiment 1 were used on 2 sets of the samples to simulate severe (FL <1.0 g·L^-1) and mild hypofibrinogenemia (FL 1.0-1.7 g·L^-1). The third set of samples was venom-free. All samples were used for platelet counts, prothrombin time (PT)/international normalized ratio (INR)/activated partial thromboplastin time (aPTT), and 2 bedside clotting tests. Diagnostic parameters were calculated against the target FL of <1.0 g·L^-1 and <1.7 g·L^-1.

RESULTS

Twenty-five subjects were enrolled in Experiment 2. On referencing normal cutoff values (platelet count >150,000 cells/mm³, venous clotting time <15 min, normal 20-min whole blood clotting time, INR <1.2, aPTT <30), we found abnormalities of 5, 0, 0, 3, and 22%, respectively. The highest correlation with hypofibrinogenemia was provided by PT/INR. For an FL of <1.0 g·L^-1, PT and INR revealed the highest areas under the receiver operating characteristic curve, 0.76 (95% CI, 0.55-0.97) and 0.76 (95% CI, 0.57-0.97), respectively. The highest accuracy and the highest sensitivity were provided by PT/INR.

CONCLUSIONS

PT/INR could be used as a diagnostic test for severe hypofibrinogenemia in GPV envenomation because of its high accuracy and area under the receiver operating characteristic curve.

Inflammation and Oxidative Stress in Snakebite Envenomation: A Brief Descriptive Review and Clinical Implications

Snakebite envenoming is a pathological condition which may occur in response to the injection of venom. Snake venoms contain a complex mixture of biologically active molecules which are responsible for a broad spectrum of clinical manifestations, ranging from local tissue injuries to fatal complications. Snake venom administration commonly provokes local tissue injury often associated with systemic effects, including neurotoxic and cardiotoxic manifestations, bleeding, acute kidney injury, and rhabdomyolysis. An important spectrum of pathogenesis of snake envenomation is the generation of reactive oxygen species (ROS), which can directly provoke tissue damage and also potentiate the deleterious consequences of inflammation at the bite site. Snake venom components known to induce oxidative stress include phospholipases A₂, metalloproteinases, three-finger toxins, and L-amino acid oxidase. Clear evidence is mounting suggesting that inflammation and oxidative stress participate in the destructive effects of envenoming, including acute renal failure, tissue necrosis, and unusual susceptibility to bleed (hemorrhage), mostly due to hypocoagulability, neuro/cardio toxicity, and myonecrosis. Impaired regulation of oxidative stress may also set the stage for secondary/long-term complications of snakebite envenomation such as musculoskeletal disabilities. Some aspects of natural antioxidant therapeutic options are discussed in this review.

Hypocholesterolaemia as a prognostic factor in venomous snakebite: a retrospective study from a single centre in Kerala, India

BACKGROUND

Studies have suggested a association between serum cholesterol values and severity of envenoming. The objective of the study was to correlate the serum cholesterol levels with severity of envenoming in victims of snakebite, across snake species in our patient population.

METHODS

Retrospective secondary data analysis of health records of a cohort of snakebite victims treated at Little Flower Hospital, Angamaly, Kerala during June 2006-January 2008 was performed. The cholesterol values were assessed in 205 consecutive patients admitted with snakebite envenoming, within 24 h of admission and 10 h of overnight fasting. Lipid fractions were estimated from fasting serum through the standard CHOD-PAP method on a Hitachi analyzer. The cholesterol level was compared between victims with mild and serious envenoming to assess the proportion among each category with a low cholesterol (defined as ≤150 mg/dl as per institutional criteria). In addition, low cholesterol as a marker of severity was compared with other laboratory parameters suggesting severe envenoming such as low fibrinogen, low platelet count, neutrophilia, elevated creatinine, d-dimer, hepatic transaminases and albuminuria.

RESULTS

Of the 146 victims with serious degree of snakebite envenoming 116 (79%) had low cholesterol values ≤150 mg%, while 30 (21%) had values >150 mg%. Of the patients with low cholesterol, 116 (78%) had serious envenoming, while 22% had mild envenoming. By contrast, 30 patients (21%) had values >150 mg%. The risk of moderate-severe envenoming with low cholesterol was 2.7 times (170%) that of victims with normal or high cholesterol on admission.

CONCLUSIONS

A low cholesterol on admission in victims of snake envenoming suggested a more severe degree of envenoming and likelihood of complications.

A Combined Bioassay and Nanofractionation Approach to Investigate the Anticoagulant Toxins of Mamba and Cobra Venoms and Their Inhibition by Varespladib

Envenomation by elapid snakes primarily results in neurotoxic symptoms and, consequently, are the primary focus of therapeutic research concerning such venoms. However, mounting evidence suggests these venoms can additionally cause coagulopathic symptoms, as demonstrated by some Asian elapids and African spitting cobras. This study sought to investigate the coagulopathic potential of venoms from medically important elapids of the genera Naja (true cobras), Hemachatus (rinkhals), and Dendroaspis (mambas). Crude venoms were bioassayed for coagulant effects using a plasma coagulation assay before RPLC/MS was used to separate and identify venom toxins in parallel with a nanofractionation module. Subsequently, coagulation bioassays were performed on the nanofractionated toxins, along with in-solution tryptic digestion and proteomics analysis. These experiments were then repeated on both crude venoms and on the nanofractionated venom toxins with the addition of either the phospholipase A₂ (PLA₂) inhibitor varespladib or the snake venom metalloproteinase (SVMP) inhibitor marimastat. Our results demonstrate that various African elapid venoms have an anticoagulant effect, and that this activity is significantly reduced for cobra venoms by the addition of varespladib, though this inhibitor had no effect against anticoagulation caused by mamba venoms. Marimastat showed limited capacity to reduce anticoagulation in elapids, affecting only N. haje and H. haemachatus venom at higher doses. Proteomic analysis of nanofractionated toxins revealed that the anticoagulant toxins in cobra venoms were both acidic and basic PLA₂s, while the causative toxins in mamba venoms remain uncertain. This implies that while PLA₂ inhibitors such as varespladib and metalloproteinase inhibitors such as marimastat are viable candidates for novel snakebite treatments, they are not likely to be effective against mamba envenomings.

Early Adverse Reactions to Snake Antivenom: Poison Center Data Analysis

Antivenom is an essential treatment for snake envenomation; however, early adverse reactions (EARs) are major limitations to its use. We performed a retrospective cross-sectional study using Ramathibodi Poison Center data (January 2016 to December 2017) to clarify the incidence and severity of EARs following different F(ab’)2 antivenoms. Among 1006 envenomed patients, 684 (68%) received antivenom therapy with a total of 1157 doses, mostly green pit viper antivenom. The overall EAR incidence and rate were 22. 5% (154/684) and 15% (173/1157), respectively. The EAR rate following each type of antivenom was >10%, except for Russell’s viper antivenom (2.9%); the severe reaction rate was 2.6% (30/1157). Malayan pit viper bites caused a high incidence of EARs (37.8%) and the highest EAR rate (22.3%). Fifty-two cases developed anaphylaxis. All EARs occurred within 2 h after treatment initiation. No deaths were attributed to EARs. The duration of administration was significantly different between doses of antivenom that induced EARs and those that did not. In conclusion, all types and every dose of antivenom should be infused for 30−60 min. Preparation of resuscitation equipment and continuous clinical observation are crucial for at least 2 h after administration, and prompt treatment should be provided when EARs occur.

The impact of climate change on the burden of snakebite: Evidence synthesis and implications for primary healthcare

Introduction

Snakebite is a public health problem in rural areas of South Asia, Africa and South America presenting mostly in primary care. Climate change and associated extreme weather events are expected to modify the snake-human-environment interface leading to a change in the burden of snakebite. Understanding this change is essential to ensure the preparedness of primary care and public health systems.

Methods

We searched five electronic databases and supplemented them with other methods to identify eight studies on the effect of climate change on the burden of snakebite. We summarised the results thematically.

Results

Available evidence is limited but estimates a geographic shift in risk of snakebite: northwards in North America and southwards in South America and in Mozambique. One study from Sri Lanka estimated a 31.3% increase in the incidence of snakebite. Based on limited evidence, the incidence of snakebite was not associated with tropical storms/hurricanes and droughts in the United States but associated with heatwaves in Israel.

Conclusion

The impact of climate change and associated extreme weather events and anthropogenic changes on mortality, morbidity and socioeconomic burden of snakebite. Transdisciplinary approaches can help understand these complex phenomena better. There is almost no evidence available in high-burden nations of South Asia and sub-Saharan Africa. Community-based approaches for biodiversity and prevention, the institution of longitudinal studies, together with improving the resilience of primary care and public health systems are required to mitigate the impact of climate change on snakebite.

Bites by Non-Native Reptiles in France: Species, Circumstances and Outcome

We aimed to make an exhaustive assessment of circumstances of bites by exotic reptiles bred in France. A retrospective observational study was conducted in all the reported cases from 2000 to 2020 in French poison control centers (PCCs). Two hundred and eighteen cases of bites were recorded. The sex ratio (M/F) of the patients was 1.79 and the mean age of the patients was 29.0 ± 15.8 years. Twenty-two cases (10.1%) occurred during the deep night. One hundred and eighty-six bites (85.7%) occurred in a private context; however, there were more cases of high severity when it occurred in a professional setting (60.0% vs. 11.2%, p < 0.01). The feeding/nursing activity accounted for 54.7% cases. Forty-three species of snake were identified; 28 were considered venomous. There were no deaths among the patients in the study. Most of the cases (85.8%) were of mild severity. All of the patients bitten by a venomous reptile were hospitalized: 10 patients received an antivenom; and 2 required surgery. Bites occurred at home and by a small number of popular non-venomous reptile species (pythons and boas, colubrids). These occurred mainly when handling the animals. The rare envenomations were mainly by Asian and American crotalids, followed by elapids. One-third of them were treated with antivenom when available.

Bites by exotic snakes reported to the UK National Poisons Information Service 2009-2020

Introduction: Snakebite is recognised as a neglected tropical disease and a cause of substantial morbidity and mortality. Whilst the most medically important snakes are typically native of Asia, Africa, Latin America and Oceania, the possibility of encountering these snakes is no longer limited by geography due to an increasing number of exotic (non-native) snakes being held in captivity.Methods: A retrospective review of snakebite enquiries to the UK National Poisons Information Service (NPIS) between 2009 and 2020. Enquiries about the European adder (Vipera berus) or where the identity of the snake was unknown were excluded.Results: There were 321 exotic snakebites in 300 patients involving 68 different species during this period. Ten patients were bitten on more than one occasion. The majority of patients (64.5%) were male. Most bites were inflicted by snakes of the family Colubridae (184/321, 57.3%); seventeen bites resulted in moderate symptoms (predominantly swelling of the bitten limb). There were 30 (9.3%) bites by Viperidae and 14 (4.3%) bites by Elapidae. All severe cases (n = 15) resulted from bites by either Viperidae (n = 10) or Elapidae (n = 5). Antivenom was given in 17 cases. One fatality was recorded.Conclusions: Despite their low incidence, exotic snakebites present a substantial challenge for UK healthcare professionals. Although rare, these bites typically occur in individuals (usually male) who keep snakes as part of their occupation or hobby and are therefore at risk of multiple bites. Bites can result in venom hypersensitisation and the risk of venom-induced anaphylaxis. Rapid access to expert clinical advice is available in the UK on a 24-hour basis through the National Poisons Information Service and is strongly recommended in all cases of exotic snakebite.

A First Look at the Inhibitory Potential of Urospatha sagittifolia (Araceae) Ethanolic Extract for Bothrops atrox Snakebite Envenomation

Bothrops atrox snakebites are a relevant problem in the Amazon basin. In this biodiverse region, the ethnomedicinal approach plays an important role as an alternative to antivenom therapy. Urospatha sagittifolia (Araceae) is a plant used for this purpose; however, its neutralizing properties have not been scientifically accessed. To fill this gap, we investigated the ability of U. sagittifolia to modulate the catalytic activity of Bothrops atrox venom, and their toxic consequences, such as local damage and lethality. The venom profile of B. atrox was assessed by chromatography and electrophoresis. Inhibition of the three main enzymatic and medically important toxins from the venom was evaluated using synthetic substrates and quantified by chromogenic activity assays. Additionally, the neutralization of lethality, hemorrhage and edema were investigated by in vivo assays. The possible interactions between venom proteins and plant molecules were visualized by polyacrylamide gel electrophoresis. Finally, the phytochemical constituents present in the ethanolic extract were determined by qualitative and quantitative analyses. The ethanolic extract reduced the activity of the three main enzymes of venom target, achieving ranges from 19% to 81% of inhibition. Our in vivo venom neuralizations assays showed a significant inhibition of edema (38.72%) and hemorrhage (42.90%). Additionally, lethality was remarkably counteracted. The highest extract ratio evaluated had a 75% survival rate. Our data support the biomedical value of U. sagittifolia as a source of natural enzyme inhibitors able to neutralize catalytically active B. atrox venom toxins and their toxic effects.