WHO's Snakebite Envenoming Strategy for prevention and control

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.

ASSESSING TARGET SPECIFICITY OF THE SMALL MOLECULE INHIBITOR MARIMASTAT TO SNAKE VENOM TOXINS: A NOVEL APPLICATION OF THERMAL PROTEOME PROFILING

New treatments that circumvent the pitfalls of traditional antivenom therapies are critical to address the problem of snakebite globally. Numerous snake venom toxin inhibitors have shown promising cross-species neutralization of medically significant venom toxins in vivo and in vitro. The development of high-throughput approaches for the screening of such inhibitors could accelerate their identification, testing, and implementation, and thus holds exciting potential for improving the treatments and outcomes of snakebite envenomation worldwide. Energetics-based proteomic approaches, including Thermal Proteome Profiling (TPP) and Proteome Integral Solubility Alteration (PISA) assays, represent "deep proteomics" methods for high throughput, proteome-wide identification of drug targets and ligands. In the following study, we apply TPP and PISA methods to characterize the interactions between venom toxin proteoforms in Crotalus atrox (Western Diamondback Rattlesnake) and the snake venom metalloprotease (SVMP) inhibitor marimastat. We investigate its venom proteome-wide effects and characterize its interactions with specific SVMP proteoforms, as well as its potential targeting of non-SVMP venom toxin families. We also compare the performance of PISA thermal window and soluble supernatant with insoluble precipitate using two inhibitor concentrations, providing the first demonstration of the utility of a sensitive high-throughput PISA-based approach to assess the direct targets of small molecule inhibitors for snake venom.

Use of Antibiotics following Snakebite in the Era of Antimicrobial Stewardship

Even though there are guidelines for the management of snakebite envenoming (SBE), the use of antibiotics in this pathology remains controversial. The aim of this study is to provide a narrative review of the literature and recommendations based on the best available evidence regarding antibiotic use in SBE. We performed a narrative review of relevant literature regarding SBE and antibiotic use as prophylaxis or treatment. A total of 26 articles were included. There is wide use of antibiotics in SBE; nevertheless, infection was not necessarily documented. The antibiotics used varied according to the study, from beta lactams to lincosamide and nitroimidazoles, and from monotherapy to combined antimicrobials. The most common recommendations were to manage skin and soft tissue infections and avoid infectious complications, but these suggestions are not necessarily based on bacteriological findings. Prophylactic use of antibiotics in SBE is discouraged in most studies. Antibiotic prescription in SBE should be based on the susceptibility of microorganisms isolated from the affected tissue or identified in snakes' oral cavities. Antibiotics should be reserved only for patients with a demonstrated infection, or those at a high risk of developing an infection, i.e., presenting severe local envenoming, local signs of infection, or those with incorrect manipulation of wounds. Prospective studies are needed to correlate microbiological findings at the wound site and the response to antibiotic use.

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.

Upper Extremity Crotalid Envenomation: A Review of Incidence and Recent Trends in Management of Snakebites

PURPOSE

The goal of this study was to evaluate the recent trends in the management of upper extremity Crotalid envenomation in the state of Georgia, United States.

METHODS

A retrospective review of the Georgia Poison Center database looking at the reported snakebites to the upper extremity between 2015 and 2020 was performed. Patient demographics, timing and location of injury, severity of envenomation, treatment, including use of antivenin and surgical intervention, and reported complications related to the use of antivenin was extracted.

RESULTS

A retrospective review of snakebites between 2015 and 2020 showed 2408 snakebite cases with a mean patient age of 37.4 years. Males incurred 62.8% of all bites. The highest incidence was in summer 52.5%, and between the hours of 5 PM to midnight 57.2%. Overall, 1010 (41.9%) of all bites were categorized as venomous snakebites (55.6% copperhead, 20% rattlesnake, 2.4% cottonmouth, and 22% miscellaneous [including 3 Elapid envenomations] or unidentified. The total number of venomous bites to the upper extremity was 575 (56.9%) and 567 patients received antivenin. Envenomation severity was mild in 29%, moderate in 45%, severe in 10%, and undetermined in 16% of cases. Crotalidae polyvalent immune Fab (Ovine) was the main antivenin used, with overall mean initial therapy dose of 6.2 vials and 59% of patients receiving maintenance therapy. Three patients (0.5%) had a severe anaphylactic reaction to antivenin requiring cessation of therapy. Seven patients had acute compartment syndrome of the upper extremity requiring fasciotomy (3 copperhead, 2 rattlesnake, and 2 unidentified). There was no reported mortality during this period.

CONCLUSIONS

Hand surgeons should be familiar with the management of upper extremity Crotalid envenomation. Antivenin remains the main treatment for symptomatic patients. Crotalid snakebites rarely require operative intervention.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic IV.

Empowering Health care Systems and Communities for Snakebite Envenoming Control in India

Snakebite envenoming (SBE) is a global health challenge, predominantly affecting economically disadvantaged regions. India contributes significantly to global snakebite mortality. Since 2013, the Indian Council of Medical Research (ICMR) has spearheaded efforts to combat SBE. A multi-sectoral engagement in the snakebite research projects and inputs from communities, traditional healers, and the health system have led to the creation of an Information Education and Communication (IEC) material suite, including management flowchart, information booklets, posters, and brochures, all available in local languages. These resources were broadly disseminated in high-burden regions in Maharashtra and Odisha, resulting in an approximately 10% increase in case reporting within a year. This holistic approach, engaging diverse stakeholders and addressing multiple facets of SBE, offers promise for alleviating the snakebite burden, not only in India but also in other low- and middle-income countries across South Asia, Africa, and South America, holding potential for broader positive global impact.

Snakebite Clinics and Pathogenesis: From Preclinical to Resource Mapping Studies

Amidst the global healthcare landscape, the menace of snakebite envenoming (SBE) has persisted, silently afflicting millions and annually claiming tens of thousands of lives [...].

Bothrops atrox and Bothrops lanceolatus Venoms In Vitro Investigation: Composition, Procoagulant Effects, Co-Factor Dependency, and Correction Using Antivenoms

Bothrops venoms are rich in enzymes acting on platelets and coagulation. This action is dependent on two major co-factors, i.e., calcium and phospholipids, while antivenoms variably neutralize venom-related coagulopathy effects. Our aims were (i) to describe the composition of B. atrox and B. lanceolatus venoms; (ii) to study their activity on the whole blood using rotational thromboelastometry (ROTEM); (iii) to evaluate the contribution of calcium and phospholipids in their activity; and (iv) to compare the effectiveness of four antivenoms (Bothrofav™, Inoserp™ South America, Antivipmyn™ TRI, and PoliVal-ICP™) on the procoagulant activity of these two venoms. Venom composition was comparable. Both venoms exhibited hypercoagulant effects. B. lanceolatus venom was completely dependent on calcium but less dependent on phospholipids than B. atrox venom to induce in vitro coagulation. The four antivenoms neutralized the procoagulant activity of the two venoms; however, with quantitative differences. Bothrofav™ was more effective against both venoms than the three other antivenoms. The relatively similar venom-induced effects in vitro were unexpected considering the opposite clinical manifestations resulting from envenomation (i.e., systemic bleeding with B. atrox and thrombosis with B. lanceolatus). In vivo studies are warranted to better understand the pathophysiology of systemic bleeding and thrombosis associated with Bothrops bites.

Who are the most affected by Bothrops snakebite envenoming in Brazil? A Clinical-epidemiological profile study among the regions of the country

Snakebite envenoming represents an important Neglected Tropical Disease (NTD) that mainly affects tropical and subtropical developing countries according to the World Health Organization (WHO). As a priority issue in the tropics, it is estimated that accidental encounter between snakes and humans is the leading cause of morbidity and mortality among all NTDs in the world. In Brazil, an extremely diverse country with continental dimensions, snakebite envenoming is the second leading cause of reported human envenoming. Treating the disease has been an unprecedented challenge for Brazilian Health Systems for decades. Despite access to Antivenom therapy and distributing it free of charge across the country, Brazil faces numerous issues regarding the notification process and accurate treatment targeting for at-risk populations. Thus, this study aimed to identify the temporal epidemiological dynamics of accidents caused by Bothrops snakes in Brazil, the country's major group of venomous snakes, based on secondary information from the online database provided by The Brazilian Notifiable Diseases Information System (SINAN). For this purpose, reported Bothrops snakebites between 2012 and 2021 were counted, then the data were analyzed. We looked at the frequency, occurrence, mortality rates, case fatality rate (CFR), age and gender distribution, and the time lapse between the incident and the initiation of Antivenom therapy. The data were also organized considering regional variations of the country. Throughout the studied period, a total of 202,604 cases of envenoming caused by Bothrops spp. were notified, resulting in 766 fatalities. These accidents were found to occur in variable proportions across different regions in Brazil, with notable concentrations observed in the North, Northeast, and Southeast regions. The epidemiological profile of patients varied greatly between the regions, revealing that snake envenoming is much more a social, economic, and ecological problem than a medical one. In conclusion, our study provides an overview of the clinical and epidemiological profile of envenoming by Bothrops snakes in Brazil. Notably, this is the first study to present such information in a country as vast and diverse as Brazil, encompassing a comparative analysis of its regions using SINAN data, that proves to be a very useful national tool to improve the control and management of envenoming.

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.

Structural capacity and continuum of snakebite care in the primary health care system in India: a cross-sectional assessment

BACKGROUND

In 2019, the World Health Organization, set a target to halve the burden of snakebite, by 2030, and identified 'health systems strengthening' as a key pillar of action. In India, the country with most snakebite deaths, the Union Government identified (in September 2022) training of health workers as a priority action area. In this policy context, we provide empirical evidence by analysing the most recent nationwide survey data (District Level Household and Facility Survey - 4), to assess structural capacity and continuum of snakebite care in primary health care system in India.

METHODOLOGY

We evaluated structural capacity for snakebite care under six domains: medicines, equipment, infrastructure, human resources, governance and finance, and health management information systems (HMIS). We categorised states (aspirant, performer, front-runner, achiever) based on the proportion of primary health centres (PHC) and community health centres (CHC), attaining highest possible domain score. We assessed continuum of snakebite care, district-wise, under five domains (connectivity to PHC, structural capacity of PHC, referral from PHC to higher facility, structural capacity of CHC, referral from CHC to higher facility) as adequate or not.

RESULTS

No state excelled ( front-runner or achiever) in all six domains of structural capacity in PHCs or CHCs. The broader domains (physical infrastructure, human resources for health, HMIS) were weaker compared to snakebite care medicines in most states/UTs, at both PHC and CHC levels. CHCs faced greater concerns regarding human resources and equipment availability than PHCs in many states. Among PHCs, physical infrastructure and HMIS were aspirational in all 29 assessed states, while medicines, equipment, human resources, and governance and finance were aspirational in 8 (27.6%), 2 (6.9%), 17 (58.6%), and 12 (41.4%) states respectively. For CHCs, physical infrastructure was aspirational in all 30 assessed states/UTs, whereas HMIS, medicines, equipment, human resources, and governance and finance were aspirational in 29 (96.7%), 11 (36.7%), 27 (90%), 26 (86.7%), and 3 (10%) states respectively. No district had adequate continuum of snakebite care in all domains. Except for transport availability from CHC to higher facilities (48% of districts adequate) and transport availability from PHC to higher facilities (11% of districts adequate), fewer than 2% of districts were adequate in all other domains.

CONCLUSION

Comprehensive strengthening of primary health care, across all domains, and throughout the continuum of care, instead of a piece-meal approach towards health systems strengthening, is necessitated to reduce snakebite burden in India, and possibly other high-burden nations with weak health systems. Health facility surveys are necessitated for this purpose.

Crosstalk of Inflammation and Coagulation in Bothrops Snakebite Envenoming: Endogenous Signaling Pathways and Pathophysiology

Snakebite envenoming represents a major health problem in tropical and subtropical countries. Considering the elevated number of accidents and high morbidity and mortality rates, the World Health Organization reclassified this disease to category A of neglected diseases. In Latin America, Bothrops genus snakes are mainly responsible for snakebites in humans, whose pathophysiology is characterized by local and systemic inflammatory and degradative processes, triggering prothrombotic and hemorrhagic events, which lead to various complications, organ damage, tissue loss, amputations, and death. The activation of the multicellular blood system, hemostatic alterations, and activation of the inflammatory response are all well-documented in Bothrops envenomings. However, the interface between inflammation and coagulation is still a neglected issue in the toxinology field. Thromboinflammatory pathways can play a significant role in some of the major complications of snakebite envenoming, such as stroke, venous thromboembolism, and acute kidney injury. In addition to exacerbating inflammation and cell interactions that trigger vaso-occlusion, ischemia-reperfusion processes, and, eventually, organic damage and necrosis. In this review, we discuss the role of inflammatory pathways in modulating coagulation and inducing platelet and leukocyte activation, as well as the inflammatory production mediators and induction of innate immune responses, among other mechanisms that are altered by Bothrops venoms.

Effect of the time to antivenom administration on recovery from snakebite envenoming-related coagulopathy in French Guiana

BACKGROUND

Snakebite (SB) envenoming is an acute emergency requiring an early care delivery. We aimed to search for the time to reach healthcare facilities in various regions of French Guiana (FG) and to assess the impact of time to antivenom (AV) on the correction of coagulation parameters in these patients.

METHODOLOGY

This is a prospective observational study conducted in Cayenne General Hospital between January 1st, 2016, and July 31st, 2022. We included all patients hospitalized for SB envenoming less than 48h after the bite, and receiving antivenom (AV). We assessed the time lapse between SB and medical attention and the time needed to return of the coagulation parameters to normal.

PRINCIPAL FINDINGS

Overall, 119 patients were investigated, and 48.7% were from remote areas. The median time from SB to AV therapy was 09:15 h (05:32-17:47). The time was longer in patients from remote rural locations. AV was dispensed within the first six hours after the SB in 45 cases (37.8%). Time from SB to reaching normal plasma fibrinogen concentration was 23:27 h (20:00-27:10) in patients receiving AV≤6h vs. 31:23 h (24:00-45:05) in those receiving AV>6h (p<0.001). Whereas, the time from AV administration to reach normal fibrinogen dosage was similar in the two groups.

CONCLUSIONS

Patients from rural settings in FG suffer from a delay in AV administration after SB envenoming leading to an extended time in which patients are coagulopathic. Once AV is administered, clotting parameters recover at a similar rate. Supplying remote healthcare facilities with AV and with medical teams trained in its use should be planned.

Rapid identification of bilateral adrenal and pituitary haemorrhages induced by Russell's viper envenomation results in positive patient outcome

The clinical management of snakebite envenomation (SBE) is challenging in many tropical and subtropical regions of developing countries due to the complex clinical manifestations and inadequate medical infrastructure. Some venomous snakes, such as the Indian Russell's viper (Daboia russelii) cause a wide range of rare complications in addition to their classical envenomation effects. In general, these uncommon complications are often misdiagnosed or not treated promptly due to a lack of awareness about these conditions. Thus, it is critical to report such complications to draw the attention of the healthcare and research communities to improve the clinical management and scientific research of SBE, respectively. Here, we report bilateral adrenal and pituitary haemorrhages in an SBE patient following a bite by Russell's viper in India. The initial symptoms included gum bleeding, swelling, axillary lymphadenopathy and clotting abnormalities. Despite the administration of antivenom, the patient presented palpitation, nausea, and abdominal pain, which were not recovered by combinational therapy with epinephrine and dexamethasone. Further infusion of antivenom did not address these issues and the patient displayed persistent hypotension, hypoglycaemia and hyperkalaemia suggesting an adrenal crisis. Inadequate secretion of corticosteroids was confirmed by laboratory tests, and imaging investigations revealed haemorrhages in both the adrenal and pituitary glands. The patient made a full recovery after treatment with hydrocortisone and thyroxine. This report adds to the growing evidence of rare complications induced by Russell's viper envenomations and it provides relevant guidance to diagnose and treat such complications in SBE victims.

Climate change maladaptation for health: Agricultural practice against shifting seasonal rainfall affects snakebite risk for farmers in the tropics

Snakebite affects more than 1.8 million people annually. Factors explaining snakebite variability include farmers' behaviors, snake ecology and climate. One unstudied issue is how farmers' adaptation to novel climates affect their health. Here we examined potential impacts of adaptation on snakebite using individual-based simulations, focusing on strategies meant to counteract major crop yield decline because of changing rainfall in Sri Lanka. For rubber cropping, adaptation led to a 33% increase in snakebite incidence per farmer work hour because of work during risky months, but a 17% decrease in total annual snakebites because of decreased labor in plantations overall. Rice farming adaptation decreased snakebites by 16%, because of shifting labor towards safer months, whereas tea adaptation led to a general increase. These results indicate that adaptation could have both a positive and negative effect, potentially intensified by ENSO. Our research highlights the need for assessing adaptation strategies for potential health maladaptations.

National snakebite project on capacity building of health system on prevention and management of snakebite envenoming including its complications in selected districts of Maharashtra and Odisha in India: A study protocol

BACKGROUND

Snakebite envenoming (SBE) is an acute, life-threatening emergency in tropical and subtropical countries. It is an occupational hazard and a major socioeconomic determinant. Limited awareness, superstitions, lack of trained health providers, poor utilization of anti-venom results in high mortality and morbidity. India is the snakebite capital of the world. Yet, information on awareness, knowledge, and perceptions about snakebite is limited. Data on capacity building of health systems and its potential impact is lacking. Recommended by the National Task Force on snakebite research in India, this protocol describes the National Snakebite Project aiming for capacity building of health systems on prevention and management of snakebite envenomation in Maharashtra and Odisha states.

METHODS

A cross-sectional, multi-centric study will be carried out in Shahapur, Aheri blocks of Maharashtra, and Khordha, Kasipur blocks of Odisha. The study has five phases: Phase I involves the collection of retrospective baseline data of snakebites, facility surveys, and community focus group discussions (FGDs). Phase II involves developing and implementing educational intervention programs for the community. Phase III will assess the knowledge and practices of the healthcare providers on snakebite management followed by their training in Phase IV. Phase V will evaluate the impact of the interventions on the community and healthcare system through FGDs and comparison of prospective and baseline data.

DISCUSSION

The National Snakebite Project will use a multi-sectoral approach to reduce the burden of SBE. It intends to contribute to community empowerment and capacity building of the public healthcare system on the prevention and management of SBE. The results could be useful for upscaling to other Indian states, South Asia and other tropical countries. The findings of the study will provide critical regional inputs for the revision of the National Snakebite Treatment protocol.

TRIAL REGISTRATION

Registered under the Clinical Trials Registry India no. CTRI/2021/11/038137.

Barriers and enablers of community engagement practices for the prevention of snakebite envenoming in South Asia: A qualitative exploratory study

Snakebite envenoming (SBE) is a grossly neglected tropical disease (NTD) that predominantly affects those living in rural settings in low-and-middle income countries. South Asia currently accounts for the highest global SBE-related mortality, and substantial morbidity rates. To alleviate the high burden in the region, community engagement (CE) is considered to be an integral component for optimizing SBE prevention and control. To better understand existing CE practices for SBE in the region, the experiences of SBE-CE actors concerning the barriers to, and enablers of CE practices were captured through semi-structured interviews. Fifteen key informants from India, Bangladesh and Nepal participated in the study. Important enablers included providing innovative, inclusive and continuous methods and materials, carefully planning of programs, performing monitoring and evaluation, SBE data availability, motivated and trained staff members, good organizational reputations, communication with other SBE-actors, collaborations, and the involvement of the government. Substantial barriers comprised a lack of SBE data, lack of innovative methods and materials for educational purposes, a shortage of human and physical resources, community resistance, untrained health care workers (HCWs), and ineffective traditional healing practices. In order to optimize and sustain SBE-CE practices, context-sensitive, multi-faceted approaches are needed that incorporate all these factors which influence its sustainable implementation.

Intrageneric cross-reactivity of monospecific rabbit antisera against venoms of the medically most important Bitis spp. and Echis spp. African snakes

BACKGROUND

Snakebite envenomation exerts a heavy toll in sub-Saharan Africa. The design and production of effective polyspecific antivenoms for this region demand a better understanding of the immunological characteristics of the different venoms from the most medically important snakes, to select the most appropriate venom combinations for generating antivenoms of wide neutralizing scope. Bitis spp. and Echis spp. represent the most important viperid snake genera in Africa.

METHODOLOGY/PRINCIPAL FINDINGS

Eight rabbit-derived monospecific antisera were raised against the venoms of four species of Bitis spp. and four species of Echis spp. The effects of immunization in the rabbits were assessed, as well as the development of antibody titers, as judged by immunochemical assays and neutralization of lethal, hemorrhagic, and in vitro coagulant effects. At the end of immunizations, local and pulmonary hemorrhage, together with slight increments in the plasma activity of creatine kinase (CK), were observed owing to the action of hemorrhagic and myotoxic venom components. Immunologic analyses revealed a considerable extent of cross-reactivity of monospecific antisera against heterologous venoms within each genus, although some antisera provided a more extensive cross-reactivity than others. The venoms that generated antisera with the broadest coverage were those of Bitis gabonica and B. rhinoceros within Bitis spp. and Echis leucogaster within Echis spp.

CONCLUSIONS/SIGNIFICANCE

The methodology followed in this study provides a rational basis for the selection of the best combination of venoms for generating antivenoms of high cross-reactivity against viperid venoms in sub-Saharan Africa. Results suggest that the venoms of B. gabonica, B. rhinoceros, and E. leucogaster generate antisera with the broadest cross-reactivity within their genera. These experimental results in rabbits need to be translated to large animals used in antivenom production to assess whether these predictions are reproduced in horses or sheep.

Revisiting Preclinical Observations of Several Histamine H3 Receptor Antagonists/Inverse Agonists in Cognitive Impairment, Anxiety, Depression, and Sleep-Wake Cycle Disorder

A relationship appears to exist between dysfunction of brain histamine (HA) and various neuropsychiatric brain disorders. The possible involvement of brain HA in neuropathology has gained attention recently, and its role in many (patho)physiological brain functions including memory, cognition, and sleep-wake cycle paved the way for further research on the etiology of several brain disorders. Histamine H3 receptor (H3R) evidenced in the brains of rodents and humans remains of special interest, given its unique position as a pre- and postsynaptic receptor, controlling the synthesis and release of HA as well as different other neurotransmitters in different brain regions, respectively. Despite several disappointing outcomes for several H3R antagonists/inverse agonists in clinical studies addressing their effectiveness in Alzheimer's disease (AD), Parkinson's disease (PD), and schizophrenia (SCH), numerous H3R antagonists/inverse agonists showed great potentials in modulating memory and cognition, mood, and sleep-wake cycle, thus suggesting its potential role in neurocognitive and neurodegenerative diseases such as AD, PD, SCH, narcolepsy, and major depression in preclinical rodent models. In this review, we present preclinical applications of selected H3R antagonists/inverse agonists and their pharmacological effects on cognitive impairment, anxiety, depression, and sleep-wake cycle disorders. Collectively, the current review highlights the behavioral impact of developments of H3R antagonists/inverse agonists, aiming to further encourage researchers in the preclinical drug development field to profile the potential therapeutic role of novel antagonists/inverse agonists targeting histamine H3Rs.

A mechanistic model of snakebite as a zoonosis: Envenoming incidence is driven by snake ecology, socioeconomics and its impacts on snakes

Snakebite is the only WHO-listed, not infectious neglected tropical disease (NTD), although its eco-epidemiology is similar to that of zoonotic infections: envenoming occurs after a vertebrate host contacts a human. Accordingly, snakebite risk represents the interaction between snake and human factors, but their quantification has been limited by data availability. Models of infectious disease transmission are instrumental for the mitigation of NTDs and zoonoses. Here, we represented snake-human interactions with disease transmission models to approximate geospatial estimates of snakebite incidence in Sri Lanka, a global hotspot. Snakebites and envenomings are described by the product of snake and human abundance, mirroring directly transmitted zoonoses. We found that human-snake contact rates vary according to land cover (surrogate of occupation and socioeconomic status), the impacts of humans and climate on snake abundance, and by snake species. Our findings show that modelling snakebite as zoonosis provides a mechanistic eco-epidemiological basis to understand snakebites, and the possible implications of global environmental and demographic change for the burden of snakebite.

Snakebite envenomation in children: An ongoing burden in Morocco

Introduction

Snakebites are a leading cause of mortality and permanent disabilities especially among children in tropical countries and rural areas such as Morocco. Thus, a nationwide management protocol including specific antivenom therapy along with prevention strategies was implemented to reduce the overall snakebites morbimortality.

Patients and methods

Our retrospective study aimed to describe the clinical aspects of snakebite envenomation before and after the implementation of this protocol in children admitted to the pediatric intensive care unit (PICU) in Marrakesh-Morocco for a period of 11 years.

Results

A total of 75 cases were included and were mostly male (70%) with a mean age of 10 years old. Most envenomations were mild or severe (75%) and often occurred during outdoor activities in limb extremities. Altered hemostasis frequently occurred in 67% of cases but was rarely associated with severe exteriorized hemorrhage. Moderate anemia and PNN- predominant leukocytosis were often observed at admission (52.2% and 58%) but quickly tended to normalize before 48 h. Local symptoms were the main dread as they quickly evolve to a compartment syndrome and necrosis in the absence of antivenom therapy. Fasciotomy was performed in 33% of cases while 5 children required limb amputation. Antivenom administration (n = 39) was statistically significant for rapid improvement in hemostasis disorders, reduced blood transfusions and fasciotomy for compartment syndrome as well as a shortened length of stay in PICU. The onset of acute kidney injury was observed in 18 cases but restored in most patients within 48 h (77%). Five children died of which only two had received delayed antivenom immunotherapy due to its unavailability and deferred hospital admission.

Conclusion

The advent of specific serotherapy has made it possible to optimize the management of patients and to prevent and treat local and systemic complications thus improving the overall prognosis; nevertheless, primary prevention remains the key to reducing snakebites morbimortality.

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Snakebites are a leading cause of mortality and permanent disabilities especially among children.

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Morocco represents a hot spot in northern Africa for venomous snakes where there is a wide variety of species.

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The clinical presentation is widely variable and may rapidly evolve in time.

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Snakebites are eminently preventable and manageable through community awareness and unified therapeutic action.

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The inaccessibility to healthcare structures and the occasional availability of immunotherapy continue to be the main limitation.

Effect of Agkistrodon halys antivenom in patients bit by green pit viper and the prognostic role of the disease - a retrospective cohort study

BACKGROUND AND AIMS

In Mainland China and Hong Kong, health authorities utilize Agkistrodon halys antivenom in the treatment of patients who sustained bites from green pit vipers. However, the treatment benefit of Agkistrodon halys antivenom among such patients is still controversial. The purpose of this study is to evaluate the coagulation parameters normalization time of Agkistrodon halys antivenom in patients who sustained green pit viper bites and explore independent risk factors of patient prognosis.

METHODS

Data were extracted from the Donghua Hospital Information System. Comparison of the two groups of patients - who used antivenom (GPUA) and who did not use antivenom (GPNUA) were performed using stratified analysis, univariate and multivariate ordered logistic regression models to evaluate the coagulation parameters normalization time. Univariate and multivariate ordered logistic regression models were used to explore independent risk factors of patient prognosis.

RESULTS

Between the GPUA and GPNUA groups, there is no significant difference in the coagulation parameters normalization time with the treatment of Agkistrodon halys antivenom. GPNUA consumed more cryoprecipitate and platelets and had a lower cost. The patient's severity of the bite, first coagulation profile, and dosages of fresh frozen plasma, platelet, and red cell suspension was found to be risk factors for the normalization time of coagulation parameters.

CONCLUSIONS

The therapeutic effect of Agkistrodon halys antivenom in green pit vipers bite patients is not quite satisfying. In addition, more attention should be paid to the first coagulation profile, blood clotting factors indices, platelet count (PLT), and hemoglobin when treating such patients.

A fingerprint of plasma proteome alteration after local tissue damage induced by Bothrops leucurus snake venom in mice

Bothrops spp. is responsible for about 70% of snakebites in Brazil, causing a diverse and complex pathophysiological condition. Bothrops leucurus is the main species of medical relevance found in the Atlantic coast in the Brazilian Northeast region. The pathophysiological effects involved B. leucurus snakebite as well as the organism's reaction in response to this envenoming, it has not been explored yet. Thus, edema was induced in mice paw using 1.2, 2.5, and 5.0 μg of B. leucurus venom, the percentage of edema was measured 30 min after injection and the blood plasma was collected and analyzed by shotgun proteomic strategy. We identified 80 common plasma proteins with differential abundance among the experimental groups and we can understand the early aspects of this snake envenomation, regardless of the suggestive severity of an ophidian accident. The results showed B. leucurus venom triggers a thromboinflammation scenario where family's proteins of the Serpins, Apolipoproteins, Complement factors and Component subunits, Cathepsins, Kinases, Oxidoreductases, Proteases inhibitors, Proteases, Collagens, Growth factors are related to inflammation, complement and coagulation systems, modulators platelets and neutrophils, lipid and retinoid metabolism, oxidative stress and tissue repair. Our findings set precedents for future studies in the area of early diagnosis and/or treatment of snakebites. SIGNIFICANCE: The physiopathological effects that the snake venoms can cause have been investigated through classical and reductionist tools, which allowed, so far, the identification of action mechanisms of individual components associated with specific tissue damage. The currently incomplete limitations of this knowledge must be expanded through new approaches, such as proteomics, which may represent a big leap in understanding the venom-modulated pathological process. The exploration of the complete protein set that suffer modifications by the simultaneous action of multiple toxins, provides a map of the establishment of physiopathological phenotypes, which favors the identification of multiple toxin targets, that may or may not act in synergy, as well as favoring the discovery of biomarkers and therapeutic targets for manifestations that are not neutralized by the antivenom.

A simple mortality risk prediction score for viper envenoming in India (VENOMS): A model development and validation study

BACKGROUND

Snakebite is a neglected problem with a high mortality in India. There are no simple clinical prognostic tools which can predict mortality in viper envenomings. We aimed to develop and validate a mortality-risk prediction score for patients of viper envenoming from Southern India.

METHODS

We used clinical predictors from a prospective cohort of 248 patients with syndromic diagnosis of viper envenoming and had a positive 20-minute whole blood clotting test (WBCT 20) from a tertiary-care hospital in Puducherry, India. We applied multivariable logistic regression with backward elimination approach. External validation of this score was done among 140 patients from the same centre and its performance was assessed with concordance statistic and calibration plots.

FINDINGS

The final model termed VENOMS from the term "Viper ENvenOming Mortality Score included 7 admission clinical parameters (recorded in the first 48 hours after bite): presence of overt bleeding manifestations, presence of capillary leak syndrome, haemoglobin <10 g/dL, bite to antivenom administration time > 6.5 h, systolic blood pressure < 100 mm Hg, urine output <20 mL/h in 24 h and female gender. The lowest possible VENOMS score of 0 predicted an in-hospital mortality risk of 0.06% while highest score of 12 predicted a mortality of 99.1%. The model had a concordance statistic of 0·86 (95% CI 0·79-0·94) in the validation cohort. Calibration plots indicated good agreement of predicted and observed outcomes.

CONCLUSIONS

The VENOMS score is a good predictor of the mortality in viper envenoming in southern India where Russell's viper envenoming burden is high. The score may have potential applications in triaging patients and guiding management after further validation.

Snake Envenomation

SNAKE ENVENOMATION REPRESENTS AN IMPORTANT HEALTH PROBLEM IN much of the world. In 2009, it was recognized by the World Health Organization (WHO) as a neglected tropical disease, and in 2017, it was elevated into Category A of the Neglected Tropical Diseases list, further expanding access to funding for research and antivenoms. However, snake envenomation occurs in both tropical and temperate climates and on all continents except Antarctica. Worldwide, the estimated number of annual deaths due to snake envenomation (80,000 to 130,000) is similar to the estimate for drug-resistant tuberculosis and for multiple myeloma.^, In countries with adequate resources, deaths are infrequent (e.g., <6 deaths per year in the United States, despite the occurrence of 7000 to 8000 bites), but in countries without adequate resources, deaths may number in the tens of thousands. Venomous snakes kept as pets are not rare, and physicians anywhere might be called on to manage envenomation by a nonnative snake. Important advances have occurred in our understanding of the biology of venom and the management of snake envenomation since this topic was last addressed in the Journal two decades ago. For the general provider, it is important to understand the spectrum of snake envenomation effects and approaches to management and to obtain specific guidance, when needed.

Epidemiological study of snakebite cases in Sikkim: Risk modeling with regard to the habitat suitability of common venomous snakes

Background

Snakebite envenoming is listed as category ‘A’ Neglected Tropical Disease. To achieve the target of WHO (World Health Organization) 2019, it becomes necessary to understand various attributes associated with snakebite including community awareness, improvisation of medical facilities and to map the potential distribution of venomous snakes responsible for the bite. Hence this study is conducted in Sikkim, India to understand the epidemiology of snakebite in Sikkim. The potential distribution and risk mapping of five common venomous snakes are done for effective management of snakebite cases.

Methods and findings

The snakebite cases registered in six district hospitals and four PHCs (Primary Health Centers) of Sikkim were collected from the year 2011 to 2018. Community survey was also conducted to supplement the data. Ecological Niche Modeling (ENM) was performed to predict the potential habitat of five common venomous snakes of Sikkim. The risk modeling of snakebite cases was done at the level of Gram Panchayat Unit (GPU) using Geographically Weighted Regression (GWR) and Ordinary Linear Square (OLS) model. We found higher number of male victims inflicted with snakebite envenomation. The potential distribution of the five venomous snakes showed satisfactory mean AUC (Area under Curve) value. Both the models showed significant positive association of snakebite cases with habitat suitability of the venomous snakes. Hospital data revealed no death cases whereas community data reported 24 deaths.

Conclusions

Death from snakebite reflected in community data but not in hospital data strongly indicates the people’s belief in traditional medicine. Though people of Sikkim have rich traditional knowledge, in case of snakebite traditional practices may be ineffective leading to loss of life. Sensitizing people and improving medical facilities along with proper transport facilities in rural areas might significantly reduce the snakebite casualties in the state.

Snakebite is a global burden especially inflicting despair and torment among agronomist rural population of the society. This study has been conducted in small state of Sikkim in India which has not been actually considered so far in any of the national statistical condensation of snakebite cases. There are around 19 venomous snakes found in Sikkim of which five common ones co-exist with humans. Such co-existence may lead to unintentional encounter posing life threatening snakebite. People of Sikkim have strong belief on traditional healers for treatment of snakebite which results in mortality and morbidity. The present epidemiological study provides the baseline information compiling both hospital and community data and predict the areas having higher risk of snakebite envenomation in Sikkim. This study will help the authorities for better preparedness to deal with snakebite emergency to achieve minimum or no mortality. Potential risk mapping will help the health department for stocking anti-venom in nearby health centers. Most importantly, this study will create awareness among the people and the authority about snakebite which is considered as neglected tropical disease.

Development of a Broad-Spectrum Antiserum against Cobra Venoms Using Recombinant Three-Finger Toxins

Three-finger toxins (3FTXs) are the most clinically relevant components in cobra (genus Naja) venoms. Administration of the antivenom is the recommended treatment for the snakebite envenomings, while the efficacy to cross-neutralize the different cobra species is typically limited, which is presumably due to intra-specific variation of the 3FTXs composition in cobra venoms. Targeting the clinically relevant venom components has been considered as an important factor for novel antivenom design. Here, we used the recombinant type of long-chain α-neurotoxins (P01391), short-chain α-neurotoxins (P60770), and cardiotoxin A3 (P60301) to generate a new immunogen formulation and investigated the potency of the resulting antiserum against the venom lethality of three medially important cobras in Asia, including the Thai monocled cobra (Naja kaouthia), the Taiwan cobra (Naja atra), and the Thai spitting cobra (Naja Siamensis) snake species. With the fusion of protein disulfide isomerase and the low-temperature settings, the correct disulfide bonds were built on these recombinant 3FTXs (r3FTXs), which were confirmed by the circular dichroism spectra and tandem mass spectrometry. Immunization with r3FTX was able to induce the specific antibody response to the native 3FTXs in cobra venoms. Furthermore, the horse and rabbit antiserum raised by the r3FTX mixture is able to neutralize the venom lethality of the selected three medically important cobras. Thus, the study demonstrated that the r3FTXs are potential immunogens in the development of novel antivenom with broad neutralization activity for the therapeutic treatment of victims involving cobra snakes in countries.

Perceptions, awareness on snakebite envenoming among the tribal community and health care providers of Dahanu block, Palghar District in Maharashtra, India

INTRODUCTION

India has remarkably the highest number of snakebite cases contributing to nearly 50% of the global snakebite deaths. Despite this fact, there is limited knowledge and awareness regarding the management practices for snakebite in the Indian population. The study aimed to explore the knowledge, awareness, and perception of snakes and snakebites, first aid, and treatment amongst the community and the frontline health workers in a tribal block of Dahanu, Maharashtra, India.

METHODS

A cross-sectional study was carried out from June 2016 to October 2018 in the Dahanu Block, Maharashtra. Perceptions, knowledge, awareness, and first-aid practices on the snakebites among the community were studied through focus group discussions (FGDs). Semi-structured questionnaires were used to assess the knowledge, awareness, and experience of the traditional faith healers, snake rescuers, frontline health workers on the snakebites and their management. A facility check survey was conducted using pre-tested questionnaires for different levels of the government health care facilities.

RESULTS

Most of the tribal community was aware of the commonly found snakes and their hiding places. However, there was inadequate knowledge on the identification and classification of venomous snakes. Belief in a snake god, the perception that snakes will not come out during thunderstorms, change in taste sensation, the ability of tamarind seeds or magnet to reduce the venom effect were some of the superstitions reported by the tribal community. The application of a harmful method (Tourniquet) as the first aid for snakebite was practiced by the tribal community. They preferred herbal medicines and visiting the traditional faith healers before shifting the patient to the government health facility. The knowledge on the ability to identify venomous snakebites and anti-venom was significantly higher amongst nurses and accredited social health activists (ASHAs) than auxiliary nurse midwives (ANMs) and multi-purpose workers (MPWs) (p < 0.05). None of the traditional faith healers; but nearly 60% of snake rescuers were aware of anti-venom. Fifty percent of the medical officers in Dahanu block did not have correct knowledge about the Krait bite symptoms, and renal complications due to the Russell viper bite.

CONCLUSIONS

Inappropriate perception, inadequate awareness, and knowledge about snakes and snakebites may predispose the tribal community to increased risks of venomous snakebites. Unproven and harmful methods for snakebite treatment practiced by the community and traditional faith healers could be dangerous leading to high mortality. Therefore, a multi-sectoral approach of community awareness, mapping of vulnerable populations, capacity building of health care facility, empowerment of health care workers (HCWs) could be useful for reducing the mortality and morbidity due to snakebite envenoming in India.

Dealing with snakebite in rural Cameroon: A qualitative investigation among victims and traditional healers

BACKGROUND

Snakebite is a neglected tropical disease (NTD) affecting rural and remote populations globally, who are additionally burdened by poverty and the lack of effective healthcare systems. Delayed healthcare and use of traditional treatments are very frequent. The purpose of our study was to explore perceptions of snakes, impact of snakebite, and knowledge and opinions of different snakebite treatments with the aim of identifying opportunities for improving snakebite management.

METHODS

This is a qualitative descriptive study based on semi-structured interviews with 21 snakebite victims and 4 traditional healers in 4 villages of Akonolinga health district, Center Region, Cameroon. Analysis focused on describing participants' perceptions of snakes, the impact of snakebite on the victims' lives, and their opinions of different treatment options.

RESULTS

Respondents were fearful of snakes and knowledgeable about envenoming symptoms and treatments. The experience of snakebite led to increased vigilance and avoidance behaviours, which sometimes resulted in financial loss for the victims. A range of traditional treatments were described, including tourniquets, black-stone application and medicinal plant decoctions. However, opinions were ambivalent regarding their efficacy, depending especially on previous personal experiences. Still, traditional treatments were said to be more available and cheaper than hospital care, and in particular, than antivenom. Nevertheless, most victims preferred hospital treatment if the financial and transportation barriers were lifted. Both snakebite victims and traditional healers were of the opinion that collaboration between health services and traditional healers could help to improve snakebite management and outcomes.

CONCLUSION

Our study shows that snakebite victims are in favour of using antivenom for the treatment of snakebite and would welcome better access to it. However, its current unavailability and high cost pushes them to turn to traditional treatments. On the other hand, traditional healers are in favour of collaborating with health facilities. These results are very encouraging for the improvement of snakebite management in Cameroon along the lines of the WHO Snakebite Envenoming Strategy for Prevention and Control: ensuring access to safe and effective treatment, and increasing partnership and coordination between communities, traditional healers, and conventional caregivers.

Les envenimations vipérines en Guyane française

L’OMS classe l’envenimation vipérine comme pathologie négligée. Elle représente un problème de santé publique associé à des taux de mortalité et de morbidité importants. Notre objectif est de faire une mise au point sur les données récentes de la littérature sur l’épidémiologie et la prise en charge de l’envenimation vipérine en Guyane française. La Guyane est un département français presque entièrement recouvert par une forêt tropicale. Elle abrite une herpétofaune très riche comportant notamment les espèces du genre Bothrops (famille des Viperidae) qui provoquent le plus grand nombre de morsures et d’envenimations. La gestion des envenimations vipérines représente un défi de santé publique. En effet, la plupart des envenimations se produisent dans des zones rurales éloignées où l’accès aux soins est le plus compliqué, avec la présence d’un personnel médical peu formé à la prise en charge et l’indisponibilité de l’antivenin, ce qui constitue une véritable perte de chance pour les patients. En conclusion, dans un contexte d’efforts mondiaux visant à réduire l’impact des envenimations vipérines, la coopération internationale et l’engagement des autorités locales de santé et de la société civile sont nécessaires. En Guyane, la mise en place d’une véritable filière de soins et la mise à disposition de l’antivenin dans les structures sanitaires les plus isolées constitueraient un réel progrès sanitaire.

Towards a comprehensive research and development plan to support the control, elimination and eradication of neglected tropical diseases

To maximise the likelihood of success, global health programmes need repeated, honest appraisal of their own weaknesses, with research undertaken to address any identified gaps. There is still much to be learned to optimise work against neglected tropical diseases. To facilitate that learning, a comprehensive research and development plan is required. Here, we discuss how such a plan might be developed.

Implications of global environmental change for the burden of snakebite

Snakebite envenoming is a set of intoxication diseases that disproportionately affect people of poor socioeconomic backgrounds in tropical countries. As it is highly dependent on the environment its burden is expected to shift spatially with global anthropogenic environmental (climate, land use) and demographic change. The mechanisms underlying the changes to snakebite epidemiology are related to factors of snakes and humans. The distribution and abundance of snakes are expected to change with global warming via their thermal tolerance, while rainfall may affect the timing of key activities like feeding and reproduction. Human population growth is the primary cause of land-use change, which may impact snakes at smaller spatial scales than climate via habitat and biodiversity loss (e.g. prey availability). Human populations, on the other hand, could experience novel patterns and morbidity of snakebite envenoming, both as a result of snake responses to environmental change and due to the development of agricultural adaptations to climate change, socioeconomic and cultural changes, development and availability of better antivenoms, personal protective equipment, and mechanization of agriculture that mediate risk of encounters with snakes and their outcomes. The likely global effects of environmental and demographic change are thus context-dependent and could encompass both increasing and or snakebite burden (incidence, number of cases or morbidity), exposing new populations to snakes in temperate areas due to “tropicalization”, or by land use change-induced snake biodiversity loss, respectively. Tackling global change requires drastic measures to ensure large-scale ecosystem functionality. However, as ecosystems represent the main source of venomous snakes their conservation should be accompanied by comprehensive public health campaigns. The challenges associated with the joint efforts of biodiversity conservation and public health professionals should be considered in the global sustainability agenda in a wider context that applies to neglected tropical and zoonotic and emerging diseases.

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Distribution and abundance of snakes are expected to be affected by climate change.

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Land-use change may also impact snakes but at smaller spatial scales than climate.

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Human populations could experience novel patterns and morbidity of snakebite.

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Reducing snakebite should be accompanied by actions that protect snake diversity.

Association of a Network of Immunologic Response and Clinical Features With the Functional Recovery From Crotalinae Snakebite Envenoming

Background

The immunologic pathways activated during snakebite envenoming (SBE) are poorly described, and their association with recovery is unclear. The immunologic response in SBE could inform a prognostic model to predict recovery. The purpose of this study was to develop pre- and post-antivenom prognostic models comprised of clinical features and immunologic cytokine data that are associated with recovery from SBE.

Materials and Methods

We performed a prospective cohort study in an academic medical center emergency department. We enrolled consecutive patients with Crotalinae SBE and obtained serum samples based on previously described criteria for the Surgical Critical Care Initiative (SC2i)(ClinicalTrials.gov Identifier: NCT02182180). We assessed a standard set of clinical variables and measured 35 unique cytokines using Luminex Cytokine 35-Plex Human Panel pre- and post-antivenom administration. The Patient-Specific Functional Scale (PSFS), a well-validated patient-reported outcome of functional recovery, was assessed at 0, 7, 14, 21 and 28 days and the area under the patient curve (PSFS AUPC) determined. We performed Bayesian Belief Network (BBN) modeling to represent relationships with a diagram composed of nodes and arcs. Each node represents a cytokine or clinical feature and each arc represents a joint-probability distribution (JPD).

Results

Twenty-eight SBE patients were enrolled. Preliminary results from 24 patients with clinical data, 9 patients with pre-antivenom and 11 patients with post-antivenom cytokine data are presented. The group was mostly female (82%) with a mean age of 38.1 (SD ± 9.8) years. In the pre-antivenom model, the variables most closely associated with the PSFS AUPC are predominantly clinical features. In the post-antivenom model, cytokines are more fully incorporated into the model. The variables most closely associated with the PSFS AUPC are age, antihistamines, white blood cell count (WBC), HGF, CCL5 and VEGF. The most influential variables are age, antihistamines and EGF. Both the pre- and post-antivenom models perform well with AUCs of 0.87 and 0.90 respectively.

Discussion

Pre- and post-antivenom networks of cytokines and clinical features were associated with functional recovery measured by the PSFS AUPC over 28 days. With additional data, we can identify prognostic models using immunologic and clinical variables to predict recovery from SBE.

Novel transdisciplinary methodology for cross-sectional analysis of snakebite epidemiology at national scale

Background

Worldwide, it is estimated that snakes bite 4.5–5.4 million people annually, 2.7 million of which are envenomed, and 81,000–138,000 die. The World Health Organization reported these estimates and recognized the scarcity of large-scale, community-based, epidemiological data. In this context, we developed the “Snake-Byte” project that aims at (i) quantifying and mapping the impact of snakebite on human and animal health, and on livelihoods, (ii) developing predictive models for medical, ecological and economic indicators, and (iii) analyzing geographic accessibility to healthcare. This paper exclusively describes the methodology we developed to collect large-scale primary data on snakebite in humans and animals in two hyper-endemic countries, Cameroon and Nepal.

Methodology/Principal findings

We compared available methods on snakebite epidemiology and on multi-cluster survey development. Then, in line with those findings, we developed an original study methodology based on a multi-cluster random survey, enhanced by geospatial, One Health, and health economics components. Using a minimum hypothesized snakebite national incidence of 100/100,000/year and optimizing design effect, confidence level, and non-response margin, we calculated a sample of 61,000 people per country. This represented 11,700 households in Cameroon and 13,800 in Nepal. The random selection with probability proportional to size generated 250 clusters from all Cameroonian regions and all Nepalese Terai districts. Our household selection methodology combined spatial randomization and selection via high-resolution satellite images. After ethical approval in Switerland (CCER), Nepal (BPKIHS), and Cameroon (CNERSH), and informed written consent, our e-questionnaires included geolocated baseline demographic and socio-economic characteristics, snakebite clinical features and outcomes, healthcare expenditure, animal ownership, animal outcomes, snake identification, and service accessibility.

Conclusions/Significance

This novel transdisciplinary survey methodology was subsequently used to collect countrywide snakebite envenoming data in Nepal and Cameroon. District-level incidence data should help health authorities to channel antivenom and healthcare allocation. This methodology, or parts thereof, could be easily adapted to other countries and to other Neglected Tropical Diseases.

Snakebite envenoming was recently classified as a priority neglected tropical disease by the World Health Organization. Up to five million people are bitten, more than a million envenomed, and around 100,000 victims die, mainly in rural and remote areas of low- and middle-income countries. Snakebite envenoming not only affects victims acutely, but it can also cause long-term disability, disfiguring scars, and heavy economic burden due to treatment costs and inability to work. Previous studies have analyzed snakebite clinical, epidemiological, or socio-economic impacts independently, and little has been done to assess the impact of snakebite in animals and on the livelihoods of the communities that depend upon them.

We present an innovative, holistic, national-scale methodology that includes epidemiology, One Health, economic, and geographic information science approaches into one multi-cluster household survey. We randomly selected 250 sub-district areas from all Cameroonian regions and all Nepali Terai districts, which represented more than 61,000 participants in each country. This methodology could be adapted and implemented in other countries affected by snakebite.

Centruroides margaritatus scorpion complete venom exerts cardiovascular effects through alpha-1 adrenergic receptors

Centruroides margaritatus scorpion stings are common in Colombia. However, the cardiovascular toxicity of the venom has not been clarified.

AIM

To study the effect and mechanisms of action of the complete venom of C. margaritatus (CmV) on the murine cardiovascular system.

METHODS

We evaluated the in vivo effect of CmV LD50 on the mean arterial pressure (MABP), heart rate, and surface electrocardiogram in male adult normotensive Wistar rats. Ex vivo, we evaluated the vascular reactivity of rat aortic rings to increasing concentrations (1 to 60 μg/mL) of CmV using the blockers L-NAME, indomethacin, seratrodast, and prazosin.

RESULTS

In the first hour of poisoning, CmV increased the MABP. In the second hour after poisoning, the heart rate decreased as the normalized PR interval and QT corrected increased. After that, cardiovascular shock was demonstrated by a drastic fall in the MABP and signs of cardiac conduction system block. In aortic rings, CmV caused a direct vasoconstrictor effect mediated by alpha-1 adrenergic receptors and counteracted by nitric oxide.

CONCLUSION

The direct vascular and probably the cardiac alpha-1 effects likely explain the transient hypertension and the maintenance of cardiac function, while interval lengthening may be due to K+ channel blockage. Afterwards, the effects of both the alpha-1 pathway and the K+ channel pathway converged, resulting in fatal cardiovascular shock. This knowledge could aid in understanding the dynamics of the effects of the venom and in designing treatments to address its cardiovascular effects.

In Vitro Tests for Assessing the Neutralizing Ability of Snake Antivenoms: Toward the 3Rs Principles

There is an urgent need to strengthen the implementation of the 3Rs principle (Replacement, Reduction and Refinement) in the use of experimental animals in toxinological research and in the assessment of the neutralizing efficacy of snake antivenoms. This is a challenging task owing to the inherent complexity of snake venoms. The state of the art on this topic is hereby reviewed, with emphasis on the studies in which a correlation has been observed between in vivo toxicity tests and in vitro surrogate assays, particularly in the study of lethal activity of venoms and its neutralization. Correlations have been described with some venoms-antivenoms when using: (a) enzyme immunoassays, (b) hemagglutination, (c) enzyme assays (proteinase, phospholipase A₂), (d) in vitro coagulant effect on plasma, (e) cell culture assays for cytotoxicity, (f) functional assays for assessing neurotoxicity in vitro, (g) use of hens’ eggs, and (h) antivenomics. Additionally, the routine introduction of analgesia in these assays and the design of more ‘humane’ protocols for the lethality test are being pursued. It is expected that the next years will witness a growing awareness of the relevance of the 3Rs principles in antivenom testing, and that new in vitro alternatives and more ‘humane’ experimental designs will emerge in this field.

Clinical Features and Management of Snakebite Envenoming in French Guiana

The management of snakebite (SB) envenoming in French Guiana (FG) is based on symptomatic measures and antivenom (AV) administration (Antivipmyn Tri^®; Instituto Bioclon—Mexico). Our study aimed to assess clinical manifestations, the efficacy, and safety of Antivipmyn Tri^® in the management of SB. Our study is a prospective observational work. It was conducted in the Intensive Care Unit (ICU) of Cayenne General Hospital between 1 January 2016 and 31 December 2019. We included all patients hospitalized for SB envenoming. Our study contained three groups (without AV, three vials, and six vials Antivipmyn Tri^®). During the study period, 133 patients were included. The main clinical symptoms were edema (98.5%), pain (97.7%), systemic hemorrhage (18%), blister (14.3%), and local hemorrhage (14.3%). AV was prescribed for 83 patients (62.3%), and 17 of them (20%) developed early adverse reactions. Biological parameters at admission showed defibrinogenation in 124 cases (93.2%), International Normalized Ratio (INR) > 2 in 104 cases (78.2%), and partial thromboplastin time (PTT) > 1.5 in 74 cases (55.6%). The time from SB to AV was 9:00 (5:22–20:40). The median time from SB to achieve a normal dosage of fibrinogen was 47:00 vs. 25:30, that of Factor II was 24:55 vs. 15:10, that of Factor V was 31:42 vs. 19:42, and that of Factor VIII was 21:30 vs. 10:20 in patients without and with AV, respectively, (p < 0.001 for all factors). Patients receiving Antivipmyn Tri^® showed a reduction in the time to return to normal clotting tests, as compared to those who did not. We suggest assessing other antivenoms available in the region to compare their efficacy and safety with Antivipmyn Tri^® in FG.

The prevalence of noma in northwest Nigeria

Background

Noma, a rapidly progressing infection of the oral cavity, mainly affects children. The true burden is unknown. This study reports estimated noma prevalence in children in northwest Nigeria.

Methods

Oral screening was performed on all ≤15 year olds, with caretaker consent, in selected households during this cross-sectional survey. Noma stages were classified using WHO criteria and caretakers answered survey questions. The prevalence of noma was estimated stratified by age group (0–5 and 6–15 years). Factors associated with noma were estimated using logistic regression.

Results

A total of 177 clusters, 3499 households and 7122 children were included. In this sample, 4239 (59.8%) were 0–5 years and 3692 (52.1%) were female. Simple gingivitis was identified in 3.1% (n=181; 95% CI 2.6 to 3.8), acute necrotising gingivitis in 0.1% (n=10; CI 0.1 to 0.3) and oedema in 0.05% (n=3; CI 0.02 to 0.2). No cases of late-stage noma were detected. Multivariable analysis in the group aged 0–5 years showed having a well as the drinking water source (adjusted odds ratio (aOR) 2.1; CI 1.2 to 3.6) and being aged 3–5 years (aOR 3.9; CI 2.1 to 7.8) was associated with being a noma case. In 6–15 year olds, being male (aOR 1.5; CI 1.0 to 2.2) was associated with being a noma case and preparing pap once or more per week (aOR 0.4; CI 0.2 to 0.8) was associated with not having noma. We estimated that 129120 (CI 105294 to 1 52 947) individuals <15 years of age would have any stage of noma at the time of the survey within the two states. Most of these cases (93%; n=120 082) would be children with simple gingivitis.

Conclusions

Our study identified a high prevalence of children at risk of developing advanced noma. This disease is important but neglected and therefore merits inclusion in the WHO neglected tropical diseases list.

Long-term sequelae secondary to snakebite envenoming: a single centre retrospective study in a Costa Rican paediatric hospital

OBJECTIVES

Although devastating acute effects associated with snake envenoming are well described, the long-term sequelae resulting from these envenomings have not been adequately addressed, especially in the paediatric population. The aim of our study is to describe the clinical characteristics among paediatric patients in Costa Rica who developed long-term sequelae secondary to snakebite envenoming.

DESIGN

Retrospective descriptive study of paediatric patients under 13 years who were admitted with a history of a recent snakebite at the National Children's Hospital in Costa Rica from January 2001 to December 2014.

RESULTS

We enrolled 74 patients admitted to our centre due to envenoming, and separated those who did not develop sequelae (50 patients) from those who did (24 patients). Of those who presented acute complications during hospitalisation, local wound infection and clinically diagnosed compartmental syndrome were significantly higher in the group that developed sequelae thereafter. Hypertrophic scars (66.7%), functional limitation of affected limb (37.5%) and the need of skin graft (37.5%) were the most common sequelae. The median follow-up of patients with long-term sequelae after discharge was 25.4 months (5.6-59.4). No deaths were reported during this time period.

CONCLUSIONS

Given the high economic, personal and healthcare burden that entails follow-up of these patients, efforts should be carried out to prevent the factors associated with sequelae among the affected population.

Philodryas (Serpentes: Dipsadidae) Envenomation, a Neglected Issue in Chile

Snakebite envenomation is considered a neglected tropical disease, although it also occurs outside the tropics. In this work, we analyzed the literature on Philodryas species in Chile (Philodryaschamissonis, P.simonsii, and P.tachymenoides) from 1834 to 2019, searching for epidemiological, clinical, and molecular aspects of envenomation. Ninety-one percent of the studies found regarded taxonomy, ecology, and natural history, suggesting that snakebites and venom toxins are a neglected issue in Chile. All snakebite cases reported and toxicological studies concerned the species Philodryaschamissonis. Using 185 distributional records from the literature and museum collections for this species, we show for the first time that the reported snakebite cases correlate with human population density, occurring in the Valparaiso and Metropolitan regions in Central Chile. The reduced number of snakebite cases, which were previously considered as having a low incidence in Chile, may be a consequence of under-reported cases, probably due to the inadequate publication or scarce research on this issue. Absence of information about official pharmacological treatment, post-envenoming sequels, clinical management of particular patient groups (e.g., with non-communicable diseases, pregnant women, and the elderly) was also detected. In conclusion, despite having over 185 years of literature on Chilean snakes, knowledge on the envenomation of Philodryas genus remains scarce, seriously affecting adequate medical handling during an ophidic accident. This review highlights the need to develop deep research in this area and urgent improvements to the management of this disease in Chile.