Snakebite envenoming from a global perspective: Towards an integrated approach

Effectiveness of late and very late antivenom administration on recovery from snakebite-induced coagulopathy in French Guiana: a population-based study

Background

Snakebite (SB) envenoming is an acute emergency requiring early care delivery. However, sometimes, patients can take several hours before receiving antivenom (AV). We conducted this study to assess the effectiveness of antivenom in the recovery of clotting parameters in patients consulting tardily after SB envenoming in French Guiana. The primary endpoint of our study was to investigate the time needed from SB to recovery from SB-induced coagulopathy. The secondary endpoint was to investigate the time needed from AV administration to recovery from SB-induced coagulopathy in patients receiving AV (late or very late administration).

Methods

This prospective observational study was conducted in the Intensive Care Unit (ICU) of Cayenne General Hospital between January 2016 and September 2023. We included all patients hospitalized for SB envenoming who either did not receive AV or received it more than 6 h after SB. We excluded patients who received antivenom in less than 6 h from the SB and those who received incomplete AV doses.

Findings

We included 58 patients in the No AV group, 51 in the late AV group (6 h ≤ AV < 12 h), and 50 in the very late AV group (AV≥12 h). The median age of patients was 42 years (IQR: 29-53), 65.4% were male and 34.6% were female (104 and 55 out of 159 patients) without difference regarding the demographic parameters between groups. Data regarding ethnicity was not available. The median time from SB to AV was 8.5 h (IQR: 6.9-10) in the late AV group and 21.1 h (IQR: 16.7-27.4) in the very late AV group (p < 0.001). The time from SB to normal clotting parameters was shorter in patients receiving late AV than in those receiving very late AV and those not receiving AV. No differences were observed in the time from SB and recovery of fibrinogen and activated partial thromboplastin time (aPTT) between very late AV and no AV. However, the International Normalized Ratio (INR) recovery was shorter in the very late AV group than in the no AV group. On the other hand, the time from AV to normal fibrinogen was shorter in patients receiving very late AV than in patients receiving late AV (Log-Rank = 0.020). Meanwhile, the time from AV to normal INR or normal aPTT was similar in patients receiving very late AV compared to patients receiving late AV (Log-Rank = 0.722 and 0.740, respectively).

Interpretation

Late AV administration effectively reverses coagulopathic manifestations after SB envenoming. However, very late AV administration did not improve the correction of some clotting parameters when compared to patients not receiving AV. Our findings could be explained by the combination of venom toxicokinetics and the kinetics of the synthesis of clotting factors.

Funding

No funding.

The incidence of snakebite in South Africa and the challenges associated with lack of reporting

BACKGROUND

Snakebite is a public health challenge that has a substantial impact on humans and snakes. Annually, millions of people are affected by snakebite globally but there is a paucity of detailed data on snakebite incidences. The aim of this study was to assess the patterns of snakebite incidences in South Africa.

METHODS

We collected data from hospital records, information from the National Snakebite Database and records from the AfriTox Telelog database from 2011 to 2024.

RESULTS

The combined dataset showed that 3496 snakebite incidences have been recorded over 12.5 years. The prevalence was calculated to be 5.63 per 100 000 individuals of the population for South Africa, with the highest prevalence in KwaZulu-Natal (8.89). Males made up 65.9% of snakebite incidences and most incidences were recorded between November and March. The snake species responsible for most snakebite incidences was Bitis arietans.

CONCLUSION

Snakebite is generally well managed in South Africa with few recorded deaths despite the relatively high number of bites. However, incidents are often not recorded or have missing information particularly regarding the circumstances of the bite. Our study provides insight on the snake species responsible for snakebite incidences in South Africa and can be used to create prevention measures.

Spatial Accessibility Analysis of Snake Antivenom

Objectives

To analyze the spatial accessibility of antivenom immunizing agents equipped hospitals in Hainan Province.

Methods

This paper analyzes the spatial accessibility of medical institutions equipped with different types of snake antivenom using network analysis and two-step mobile search method, and evaluates the service level and spatial accessibility of medical institutions equipped with different types of antivenom immunizing agents in Hainan Province from the perspectives of both supply and demand.

Results

The number of people in Hainan Province who need to spend more than 1 h to reach an Agkistrodon Hyalys antivenom, Naja antivenom, Bungarus Multicnctus antivenom, Agkistrodon Acutus antivenom equipped hospital, and equipped with antivenom for all species of snakes in the country is approximately 856,000, 231,300, 3,071,000, 2,666,000 and 4,721,000 people, respectively. In the results of accessibility of hospital beds/health technicians equipped with antivenom in Hainan Province, Haikou and Sanya cities had the highest accessibility.

Conclusion

The accessibility of hospitals equipped with antivenom in Hainan Province is unevenly distributed, with areas of high accessibility in the southern and northern regions and accessibility in the rest of the country to be improved.

Ethnomedicinal breakthroughs in snake bite therapy: From folklore to forefront

Snakebite envenomation is a critical public health issue, especially in tropical regions like India, resulting in significant morbidity and mortality. This review explores the potential of ethnomedicinal herbs as adjunct therapies to conventional antivenoms, addressing challenges such as the high cost, limited availability, and side effects of traditional antivenoms. The study emphasizes regional and species-specific variations in snake venom that complicate antivenom development and highlights the pharmacological potential of certain medicinal plants in mitigating venom effects. These plants offer an affordable, accessible alternative, though their efficacy can vary due to regional venom differences. Additionally, the review discusses the role of bioinformatics in advancing antivenom research, aiming to combine traditional knowledge with modern science to develop effective and accessible snakebite treatments in resource-limited settings.

The Amazonian snakebite burden: Unveiling seasonal dynamics in a region with tenfold higher incidence compared to the Brazilian average

BACKGROUND

Accidents caused by snakes constitute a serious public health problem in Latin America and worldwide. The situation in the Brazilian Amazon region is neglected, resulting in the highest incidence of cases per capita in the country. Furthermore, the distance from urban areas makes it difficult for the population to access timely and effective medical care, including antivenom treatment. The Brazilian Amazon is characterised by high ethnic and cultural diversity, yet it lacks robust epidemiological information that would allow for the development of surveillance and prevention policies. This study aimed to assess the epidemiological profile of individuals affected by snakebite accidents from 2007 to 2021 in a poorly studied region of the Brazilian Amazon.

METHODS

To assess the relationship between snakebite accidents, rainfall and river flood levels, cross-correlation functions were employed. Data from the public healthcare system database was used for this analysis.

RESULTS

The results indicate that the study area experiences a snakebite rate 10 times greater than the Brazilian average and double that of other Amazonian regions. The most affected victims consist of adult males residing in rural areas, with snakebite accidents being more common during the rainy season. Viperid snakes were responsible for most bites, with the lower limbs being the most common location of injury. The data revealed a positive correlation between the number of snakebite accidents both rainfall and fluvial data.

CONCLUSIONS

The accident peak coincides with the Brazil nut harvest season, a highly significant forest product for the economy of rural communities. Our data reinforces the need for public policies focused on environmental education and prevention, such as the use of boots and leg guards. These preventive measures have the potential to reduce the number of snakebites accidents by approximately 85%.

Predicting the drivers of Bothrops snakebite incidence across Brazil: A Spatial Analysis

Snakebite envenoming poses a significant public health challenge on a global basis, affecting millions of people annually and leading to complications that may result in fatalities. Brazil stands as one of the countries most impacted by snakebite envenoming, with snakes of the Bothrops genus being responsible for most bites. The current study aimed to identify the determinants of Bothrops snakebite incidence across different regions of Brazil. An ecological study was conducted using municipality-aggregated data, with snakebite incidence as the dependent variable. The study period comprised the years 2015-2021. We constructed Species Distribution Models (SDMs) for Bothrops species, and information was collected on precipitation, runoff, maximum and minimum temperatures, native forest, historical forest loss, agriculture, and pasture in each Brazilian municipality. These data were employed to assess the association between snakebite incidence and biotic, climatic, and landscape factors. The data were analyzed using Generalized Least Squares (GLS) regression. The SDMs demonstrated good performance. The average annual snakebite incidence during the study period ranged from zero to 428.89 per 100,000 inhabitants, depending on the municipality. Higher incidence rates were concentrated primarily in municipalities in the northern region of the country. In this study, we found that nationwide, areas with extensive native forests and those that have historically experienced significant loss of forest cover exhibited higher snakebite incidence rates. Additionally, areas with higher temperatures and precipitation levels, as well as greater climatic suitability for the species B. jararaca, showed significantly higher snakebite incidence rates in the South and Southeast of Brazil, respectively. These associations may be linked to increased snake abundance and active behavior, as well as to engagement in activities favoring human-snake contact in these areas. The findings of this study can contribute to the improvement of prevention and control strategies for this public health issue in Brazil.

Obscure properties of a traditional herb Pittosporum neelgherrense used to treat snakebite envenoming against Daboia russelli venoms

In tropical nations, snakebite envenomation is a significant public health issue with negative human and social effects. This is due to three factors: 1) more species of the most hazardous snakes are present; 2) emergency medical assistance is not readily available; and 3) inadequate health care. The problems caused by snakebite envenomation have been partially resolved by immunotherapy. An extensive collection of medicinal herbs is recognized to have antivenomous properties in traditional medicine. However, very few species have undergone scientific investigation, and even fewer have had their active components separated and structurally and functionally defined. In this work, the anti-venom potential of hot and cold aqueous extracts from Pittosporum neelgherrense is evaluated using an in-vitro model. The experimental results showed that 4H-pyran-4-one, 2,3-dihydro-3,5-dihydroxy-6-methyl-(11.20), 1-Undecanol (16.38), Lauryl acetate (18.25), and Cyclotridecane (19.14) were phytochemical substances whose chemical structures were recognized by GCMS. The Direct and Indirect hemorrhagic activity was found to be completely neutralized by P. neelgherrense extract (44.61% hot plant extract & 55.38% cold plant extract) and the zone (2.4 mm), respectively. The neutralization of venoms was indicated by the zone (0.5-0.9 cm) of hydrolysis production of proteolytic activity. Additionally, the results of the gelatine liquefaction study demonstrated that clot formation was not triggered by venom at low concentrations (50:50) but was instead brought on by higher concentrations. The present study suggested that the neutralization of venom by hot water extracts of P. neelgherrense is a potentially therapeutic application.

Current Technologies in Snake Venom Analysis and Applications

This comprehensive review explores the cutting-edge advancements in snake venom research, focusing on the integration of proteomics, genomics, transcriptomics, and bioinformatics. Highlighting the transformative impact of these technologies, the review delves into the genetic and ecological factors driving venom evolution, the complex molecular composition of venoms, and the regulatory mechanisms underlying toxin production. The application of synthetic biology and multi-omics approaches, collectively known as venomics, has revolutionized the field, providing deeper insights into venom function and its therapeutic potential. Despite significant progress, challenges such as the functional characterization of toxins and the development of cost-effective antivenoms remain. This review also discusses the future directions of venom research, emphasizing the need for interdisciplinary collaborations and new technologies (mRNAs, cryo-electron microscopy for structural determinations of toxin complexes, synthetic biology, and other technologies) to fully harness the biomedical potential of venoms and toxins from snakes and other animals.

Cardiotoxic Effects of Lachesis acrochorda Snake Venom in Anesthetized Wistar Rats

Ophidism is a public health problem in tropical countries, occurring predominantly in rural areas. In Colombia, among the species responsible for snakebite envenomation, inflicting high mortality, is the Chocoan bushmaster, Lachesis acrochorda, better known locally by the names "verrugosa (warty)" and "pudridora (rot-causing)". In this research, the cardiotoxic effect of the venom of L. acrochorda in male Wistar rats weighing 230 ± 20 g was evaluated. A statistical design of randomized blocks was implemented with three treated groups, injected with lyophilized venom (doses of 3.22 μg/g, 6.43 μg/g, 12.86 μg/g), and a control group injected with 0.9% saline solution. Electrocardiographic (ECG) recordings were taken from the anesthetized animals, revealing an increase in the amplitude of the P and T waves and an increase in the duration of the QT intervals in the electrocardiographic recordings. These increases were not observed in the control biomodels. In the analysis of the CK and CK-MB enzyme levels, increases were also observed in the levels of cardiac isoenzymes in the injected animals, but none in the control animals. The histopathological analyses carried out reveal that the injected animals showed effects such as interfibrillar and perivascular edema, cellular shortening of the cardiomyocytes, foci with tissue destructuring, and necrosis with contraction bands. In conclusion, the venom of the Lachesis acrochorda snake increases the P and T waves and the QT interval and increases the CK and CK-MB enzymes in the blood. Additionally, it causes interfibrillar and perivascular edema in the cardiac tissue, cardiocytolysis, and contraction bands.

From fangs to antidotes: A scoping review on snakebite burden, species, and antivenoms in the Eastern Mediterranean Region

BACKGROUND

Snake bites cause considerable morbidity and mortality worldwide, yet evidence from low- and middle-income countries remains fragmented. This is particularly the case in Eastern Mediterranean Region where available data on snake bites is relatively weak. Without reliable data, it is difficult to make the case for greater visibility and investment to address the snakebite burden in this Region. A scoping review was therefore conducted to summarize evidence on snake bites in countries of the Eastern Mediterranean.

METHODOLOGY/PRINCIPAL FINDINGS

The review employed manual and electronic searching methods of four databases plus Google Scholar, ultimately including 196 records from 20 countries published between 2000 and 2023. More than half originated from Iran, Morocco, and Pakistan. Many records lacked information on permanent sequalae, disability, snake species, and types and sources of antivenoms. When identified, offending snakes belonged to 30 species. Use of more than 12 types of antivenoms were described across the Region, and some were not specific to indigenous species.

CONCLUSION/SIGNIFICANCE

Despite the relatively large number of publications identified, the data were concentrated in just a few countries in the Region, and there was little or no information available for the remainder. As is the case worldwide, disability associated with snake bites was poorly characterized and quantified across the Region. There is an urgent need for concrete action at national and regional levels to enhance epidemiological surveillance, research, and the collection of clinical, disability and outcomes data to inform policy and public health investment. Greater regional cooperation and collaboration is also crucial for addressing this neglected disease throughout the Region.

The role of social media in public health awareness during times of war in Sudan: snakebites and scorpion stings

BACKGROUND

Snakebite envenomation (SBE) and scorpion sting envenomation (SSE) are significant neglected tropical diseases that primarily affect impoverished communities in rural areas of developing nations. A lack of understanding about snake and scorpion species and their distribution exacerbates the disabilities and fatalities caused by SBE and SSE. In Sudan, particularly in regions affected by ongoing conflicts where healthcare resources are scarce, social media platforms offer a cost-effective approach to addressing public health challenges. Our aim in this study is to highlight the benefits of using social media for data collection and health promotion in such environments.

METHODS

We present a cost-effective communication and data collection strategy implemented at the Toxic Organisms Research Centre (TORC) of the University of Khartoum, focusing on a Facebook group, "Scorpions and Snakes of Sudan", as our primary social media platform. Additionally, we discuss the lessons learned and the initial impact of this strategy on enhancing population health literacy.

RESULTS

The group community is composed of ~ 5000 members from 14 countries. During the period from January 2023 to January 2024, we received 417 enquiries about snakes and scorpions belonging to 11 families and composed of 55 species. In addition, 53 other enquiries covered a range of organisms and their tracks (e.g., spiders, skinks, chameleons, foxes, sun spiders, centipedes, lizards, moth larvae, and insect tracks). The first photographic evidence of Malpolon monspessulanus in Sudan was via the group activities. The rare species Telescopus gezirae, the Blue Nile cat snake, is also documented via the group member's queries. Recognizing the evolving nature of social media use in public health, we also address the current limitations and evidence gaps that need to be addressed to effectively translate best practices into policy.

CONCLUSION

In conclusion, utilizing Facebook as an institutional platform to share scientific information in simple Arabic language underscores the proactive roles that citizens, scientists, and public health stakeholders can play in leveraging social media for eHealth, eAwareness, and public health initiatives. This approach highlights the potential for collaborative efforts, particularly during crises, to maximize the benefits of social media in advancing public health.

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 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 thermal proteome profiling 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.

Photobiomodulation mitigates Bothrops jararacussu venom-induced damage in myoblast cells by enhancing myogenic factors and reducing cytokine production

BACKGROUND

Photobiomodulation has exhibited promise in mitigating the local effects induced by Bothrops snakebite envenoming; however, the mechanisms underlying this protection are not yet fully understood. Herein, the effectiveness of photobiomodulation effects on regenerative response of C2C12 myoblast cells following exposure to Bothrops jararacussu venom (BjsuV), as well as the mechanisms involved was investigated.

METHODOLOGY/PRINCIPAL FINDINGS

C2C12 myoblast cells were exposed to BjsuV (12.5 μg/mL) and irradiated once for 10 seconds with laser light of 660 nm (14.08 mW; 0.04 cm2; 352 mW/cm2) or 780 nm (17.6 mW; 0.04 cm2; 440 mW/ cm2) to provide energy densities of 3.52 and 4.4 J/cm2, and total energies of 0.1408 and 0.176 J, respectively. Cell migration was assessed through a wound-healing assay. The expression of MAPK p38-α, NF-Кβ, Myf5, Pax-7, MyoD, and myogenin proteins were assessed by western blotting analysis. In addition, interleukin IL1-β, IL-6, TNF-alfa and IL-10 levels were measured in the supernatant by ELISA. The PBM applied to C2C12 cells exposed to BjsuV promoted cell migration, increase the expression of myogenic factors (Pax7, MyF5, MyoD and myogenin), reduced the levels of proinflammatory cytokines, IL1-β, IL-6, TNF-alfa, and increased the levels of anti-inflammatory cytokine IL-10. In addition, PBM downregulates the expression of NF-kB, and had no effect on p38 MAKP.

CONCLUSION/SIGNIFICANCE

These data demonstrated that protection of the muscle cell by PBM seems to be related to the increase of myogenic factors as well as the modulation of inflammatory mediators. PBM therapy may offer a new therapeutic strategy to address the local effects of snakebite envenoming by promoting muscle regeneration and reducing the inflammatory process.

A Cytotoxicity Assay as an Alternative to the Murine Model for the Potency Testing of Bothrops jararaca Venom and Antivenom: An Intralaboratory Pre-validation Study

Antivenom therapy is the only specific treatment for snakebite envenomation, and antivenom potency determination is key in the efficacy assurance quality control process. Nowadays, this process relies on the in vivo murine model - thus, the development of alternative in vitro methods is imperative. In the current study, the principle of the proposed method is the ability of Bothrops venom to induce cytotoxic effects in Vero cells, and the capacity to evaluate the inhibition of this cytotoxicity by the respective antivenom. After exposure to the venom/antivenom, the relative proportions of adherent (viable) cells were evaluated by direct staining with Coomassie Blue. The optical density (OD) of the lysed cell eluate was directly proportional to the number of adherent cells. This cytotoxicity-based alternative method could represent a potential candidate for validation as a replacement for the current in vivo test. The in vitro-determined cytotoxicity of the Brazilian Bothrops reference venom (expressed as the 50% effective concentration; EC50) was 3.61 μg/ml; the in vitro-determined 50% inhibitory concentration (IC50) of the Brazilian Bothrops reference antivenom was 0.133 μl/ml. From these two values, it was possible to calculate the potency of the reference antivenom. The results from the assays exhibited a good linear response, indicating that the method could be a potential candidate replacement method for use in antivenom quality control prior to lot release, subject to further validation.

Proteomics and life-history variability of Endogenous Phospholipases A2 Inhibitors (PLIs) in Bothrops jararaca plasma

In Brazil, the genus Bothrops is responsible for most ophidian accidents. Snake venoms have a wide variety of proteins and peptides exhibiting a broad repertoire of pharmacological and toxic effects that elicit systemic injury and characteristic local effects. The snakes' natural resistance to envenomation caused by the presence of inhibitory compounds on their plasma have been extensively studied. However, the presence of these inhibitors in different developmental stages is yet to be further discussed. The aim of this study was to evaluate the ontogeny of Bothrops jararaca plasma inhibitor composition and, to this end, plasma samples of B. jararaca were obtained from different developmental stages (neonates, youngs, and adults) and sexes (female and male). SDS-PAGE, Western blotting, affinity chromatography, and mass spectrometry were performed to analyze the protein profile and interaction between B. jararaca plasma and venom proteins. In addition, the presence of γBjPLI, a PLA2 inhibitor previously identified and characterized in B. jararaca serum, was confirmed by Western blotting. According to our results, 9-17% of plasma proteins were capable of binding to venom proteins in the three developmental stages. The presence of different endogenous inhibitors and, more specifically, different PLA2 inhibitor (PLI) classes and antihemorrhagic factors were confirmed in specimens of B. jararaca from newborn by mass spectrometry. For the first time, the αPLI and βPLI were detected in B. jararaca plasma, although low or no ontogenetic and sexual correlation were found. The γPLI were more abundant in adult female, than in neonate and young female, but similar to neonate, young and adult male according to the results of mass spectrometry analysis. Our results suggest that there are proteins in the plasma of these animals that can help counteract the effects of self-envenomation from birth.

Systematic review and meta-analysis on the efficacy of Indian polyvalent antivenom against the Indian snakes of clinical significance

Snakebite in India is a severe problem as it causes a mortality rate of 58,000 and a disability rate of 140,000 every year which is the highest among any other country. Antivenom is the primary therapy for snakebite, and its manufacturing techniques have essentially stayed unaltered for over a century. Indian polyvalent antivenom, a scientifically validated medicine for treating the toxic effects of snakebites, is available against the venom of the so-called Big Four snakes namely Spectacled cobra (Naja naja), Saw-scaled viper (Echis carinatus), Russell's viper (Daboia russelli) and the Common krait (Bungarus caeruleus), responsible for majority of the deaths in India. India hosts many other species of snakes, including cobras, kraits, saw-scaled vipers, sea snakes, and pit vipers, responsible for clinically severe envenomation. Neutralization strategy has been applied to access the efficacy of antivenoms, crucial for reducing snake bite deaths and disabilities. This review aims to conduct a systematic review and meta-analysis on the neutralization efficiency of the Polyvalent Antivenom (PAV) and focus on the factors that may contribute to the poor recognition of the antivenom towards the venom toxins. Reports focusing on the investigation of antivenom efficacy were searched and collected from several databases. Preclinical studies that reported the neutralization efficacy of the commercial antivenom against the medically important snakes of India were included. The articles were screened based on the inclusion criteria and 8 studies were shortlisted for meta-analysis. Pooled proportion was calculated for the antivenom efficacy reported by the studies and was found to be statistically significant with a 95% confidence interval. The heterogenicity in the venom toxicity and neutralization potency of the antivenom was evident in the overall estimate (proportion) and individual data. We provide comprehensive evidence on antivenom efficacy against medically important snakes from various parts of India which may aid in identifying the gaps in snake envenomation therapy and the need for novel potentially improved treatment of snakebites.

Unveiling the secrets of snakes: Analysis of environmental, socioeconomic, and spatial factors associated with snakebite risk in Paraná, Southern Brazil

The state of Paraná is home to three out of the five medically significant snake genera in Brazil and lacks of snakebite epidemiology studies. This study aimed to ascertain the spatial, environmental, and socioeconomic factors associated with snakebite risk by analyzing notification data of cases in the state of Paraná. Notification and socioeconomic data were gathered from the online platforms of the National System of Notifiable Diseases (SINAN) and the Brazilian Institute of Geography and Statistics (IBGE). Land cover and land use maps were obtained from the Mapbiomas platform in raster format and subsequently converted into vectors using QGis software. The proportions of land use and land cover in square kilometers (km2) were then calculated. All acquired data were tabulated using Microsoft Excel 365 software. For spatial analysis, GeoDa software version 1.20 was utilized to calculate the Global and Local Moran indices, assessing spatial correlations. Between 2007 and 2021, 12,877 notifications were recorded, with an average incidence of 8.22/100,000 inhabitants in the state, 8166 (63.41%) caused by Bothrops, 1534 (11.91%) caused by Crotalus, 56 (0.43%) caused by Micrurus. 1703 (13.22%) caused by non-venomous snake species, and the remaining cases did not have the identified causative species. The incidents caused by Bothrops and Crotalus showed different distribution patterns. Spatial analysis revealed that key factors contributing to snakebite risk included the presence of native forests, mangroves, apicuns, and monospecific planted forests. The population group at the highest risk comprised rural residents and workers. Furthermore, the absence of basic sanitation and proper garbage collection and disposal exhibited positive correlations with snakebites. Conversely, intensive farming practices with substantial mechanization and pastures demonstrated negative spatial correlations. This study has enabled the identification of the primary factors associated with snakebite risk, facilitating more targeted efforts to prevent snakebite accidents among vulnerable populations.

Snake Venom: A Promising Source of Neurotoxins Targeting Voltage-Gated Potassium Channels

The venom derived from various sources of snakes represents a vast collection of predominantly protein-based toxins that exhibit a wide range of biological actions, including but not limited to inflammation, pain, cytotoxicity, cardiotoxicity, and neurotoxicity. The venom of a particular snake species is composed of several toxins, while the venoms of around 600 venomous snake species collectively encompass a substantial reservoir of pharmacologically intriguing compounds. Despite extensive research efforts, a significant portion of snake venoms remains uncharacterized. Recent findings have demonstrated the potential application of neurotoxins derived from snake venom in selectively targeting voltage-gated potassium channels (Kv). These neurotoxins include BPTI-Kunitz polypeptides, PLA2 neurotoxins, CRISPs, SVSPs, and various others. This study provides a comprehensive analysis of the existing literature on the significance of Kv channels in various tissues, highlighting their crucial role as proteins susceptible to modulation by diverse snake venoms. These toxins have demonstrated potential as valuable pharmacological resources and research tools for investigating the structural and functional characteristics of Kv channels.

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.

Venomous snakes of medical importance in the Brazilian state of Rio de Janeiro: habitat and taxonomy against ophidism

Snakebite envenoming is a major global health problem that kills or disables half a million people in the world's poorest countries. Identifying the biting snake and its habitat use is key to understanding snakebite eco-epidemiology and optimizing its clinical management. To prevent and combat the neglected snakebite disease, we characterize the morphology, geographic distribution, habitat use, and snakebites of medically important venomous snakes in the state of Rio de Janeiro (Brazil). Despite Philodryas spp. not being considered of medical importance by the Brazilian Ministry of Health, we also explore their data once the bites may require medical intervention, may cause death, and their consequences are underestimated. Methods: We assessed taxonomy and geographic data from specimens housed in scientific collections, the literature, and the Notifiable Diseases Information System. Our data revealed fragility in the morphological characters recommended to distinguish Bothrops jararaca from B. jararacussu, identify the subspecies of Crotalus durissus and distinguish the species of Philodryas. To help identify these species, we present an identification key to the venomous snake species from Rio de Janeiro based on the morphological data collected. We record the genera Bothrops and Micrurus in all mesoregions of the state. Here, we provide the first record of C. durissus in the Serrana region, supporting the hypothesis of geographic expansion of the species in the state. The crotalic antivenom must not be missing in Médio Paraíba, Centro-Sul Fluminense, and Serrana, where the rattlesnake C. durissus occurs. Bothrops bilineatus and Lachesis muta have historical records presented for the first time herein. However, these species are likely endangered or extinct in the state. There were 7,483 snakebites reported between 2001 and 2019, with an annual average of 393.8 cases. The Bothrops genus is responsible for the majority of accidents. The highest number of cases occurred in the Serrana region, the largest pole of family agriculture in Rio de Janeiro. We improve the identification of venomous snake species, better delimit their distribution, and update the number of cases of snakebites, thus providing greater precision in the attention to this problem in Rio de Janeiro. We emphasize the importance of clinical studies to test using bothropic-crotalic antivenom and heparin in all mesoregions to treat B. jararacussu envenomation; and mechanical ventilation, atropine, and anticholinesterases in the emergency health centers in the Metropolitana and Norte Fluminense regions due to the occurrence of the coral M. lemniscatus in these areas.

In silico screening of the phytochemicals present in Clitoria ternatea L. as the inhibitors of snake venom phospholipase A2 (PLA2)

Millions of people suffer from snake bite envenomation, and its management is a challenge, even today. Medicinal plants have attracted the researcher's attention for their outstanding advantages in treating many diseases, including snake venom poisoning. Clitoria ternatea L, is a plant popularly known for its various pharmacological effects especially, anti-snake venom property. However, the molecular mechanism behind this is poorly understood. It is reported that snake venom PLA2 is an extensively studied toxic factor. This study is meant to screen the compound's capability to act as inhibitors of the Daboia russelli snake venom PLA2 through molecular docking and dynamics studies. Our results show that among the 27 compounds taken for the study, only Kaempferol showed good interaction profile with the conserved catalytic active site residues, His48 and Asp49. The pharmacophore features of the compound also demonstrate its exact fitting at the binding pocket. Further RMSD, RMSF, Rg, and hydrogen bond analysis confirmed the stable binding of Kaempferol with PLA2 through molecular dynamic simulations for 100 ns. In addition, the MM/PBSA binding free energy calculation of the complex was also affirming the docking results. The binding free energy (BFE) of Kaempferolis better than the reference compound. ADME and Lipinski's rule of five reveals its drug like properties.Communicated by Ramaswamy H. Sarma.

Identifying the geographic distribution pattern of venomous snakes and regions of high snakebite risk in Iran

We describe species richness patterns of venomous snakes in Iran in order to produce snakebite risk prediction maps and identify gaps in regional health care centers capable of managing snakebites. We digitized distribution maps from the literature, Global Biodiversity Information Facility (GBIF), and the results of our own field studies of 24 terrestrial venomous snake species (including 4 endemic to Iran). Species richness patterns were associated with eight environmental factors. The variables have been extracted from the WorldClim dataset (bio12 = annual precipitation, bio15 = precipitation seasonality, bio17 = precipitation of the driest quarter, bio2 = mean diurnal range, bio3 = isothermality (bio2/bio7), bio4 = temperature seasonality, bio9 = mean temperature of the driest quarter and slope). Based on spatial analyses, species richness in Iran is highly affected by three environmental variables (bio12, 15, and 17) associated with precipitation. The relationship patterns among these predictors and species richness were strong and linear. The hotspot regions for venomous snakes species are concentrated on the western to southwestern and north to northeastern regions of Iran, which is partially consistent with the known Irano-Anatolian biodiversity hotspot. Because of the high number of endemic species and climatic conditions on the Iranian Plateau, the venoms of snakes distributed in those areas may contain novel properties and components.

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.

Community members and healthcare workers' priorities for the control and prevention of snakebite envenoming in Ghana

INTRODUCTION

Snakebite is one of the most neglected tropical diseases. In Ghana, there has been a limited interest in snakebite envenoming research despite evidence of high human-snake conflicts. In an effort to meet the World Health Organisation's (WHO) 2030 snakebite targets, the need for research evidence to guide policy interventions is evident. However, in setting the research agenda, community and healthcare workers' priorities are rarely considered.

METHODS

Three categories of focus groups were formed in the Ashanti and Upper West regions of Ghana, comprising of community members with and without a history of snakebite and healthcare workers who manage snakebite patients. Two separate focus group discussions were conducted with each group in each region. Using the thematic content analysis approach, the framework method was adopted for the data analysis. A predefined 15-item list of potential snakebite-associated difficulties and the WHO's 2030 snakebite strategic key activities were ranked in order of priority based on the participants' individual assessment.

RESULTS

Both acute and chronic effects of snakebite such as bite site management, rehabilitation and mental health were prioritised by the community members. Health system challenges including training, local standard treatment protocols and clinical investigations on the efficacy of available antivenoms were identified as priorities by the healthcare workers. Notably, all the participant groups highlighted the need for research into the efficacy of traditional medicines and how to promote collaborative strategies between traditional and allopathic treatment practices.

CONCLUSION

The prioritisation of chronic snakebite envenoming challenges by community members and how to live and cope with such conditions accentuate the lack of post-hospital treatment follow-ups for both mental and physical rehabilitation. To improve the quality of life of patients, it is essential to involve grassroots stakeholders in the process of developing and prioritising future research agenda.

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

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

Pathophysiological and Clinical Significance of Crotalus durissus cascavella Venom-Induced Pulmonary Impairment in a Murine Model

Crotalus venom has broad biological activity, including neurotoxic, myotoxic, hematologic, and cytotoxic compounds that induce severe systemic repercussions. We evaluated the pathophysiological and clinical significance of Crotalus durissus cascavella (Cdc) venom-induced pulmonary impairment in mice. We conducted a randomized experimental study, involving 72 animals intraperitoneally inoculated with saline solution in the control group (CG), as well as venom in the experimental group (EG). The animals were euthanized at predetermined intervals (1 h, 3 h, 6 h, 12 h, 24 h, and 48 h), and lung fragments were collected for H&E and Masson histological analysis. The CG did not present inflammatory alterations in pulmonary parenchyma. In the EG, interstitial and alveolar swelling, necrosis, septal losses followed by alveolar distensions, and areas of atelectasis in the pulmonary parenchyma were observed after three hours. The EG morphometric analysis presented pulmonary inflammatory infiltrates at all time intervals, being more significant at three and six (p = 0.035) and six and 12 h (p = 0.006). The necrosis zones were significant at intervals of one and 24 h (p = 0.001), one and 48 h (p = 0.001), and three and 48 h (p = 0.035). Crotalus durissus cascavella venom induces a diffuse, heterogeneous, and acute inflammatory injury in the pulmonary parenchyma, with potential clinical implications for respiratory mechanics and gas exchange. The early recognition and prompt treatment of this condition are essential to prevent further lung injury and to improve outcomes.

Perspectives on snakebite envenoming care needs across different sociocultural contexts and health systems: A comparative qualitative analysis among US and Brazilian health providers

With the advancements in therapeutics and available treatment options, almost all deaths and permanent disabilities from snakebite envenoming (SBE) are preventable. The challenge lies in implementing these evidence-based treatments and practices across different settings and populations. This study aims to compare data on provider perceptions of SBE care across health systems and cultural contexts to inform potential implementation science approaches. We hypothesize different health systems and cultural contexts will influence specific perceived needs to provide adequate snakebite care within central tenets of care delivery (e.g., cost, access, human resources). We previously conducted exploratory descriptive studies in the US and Brazil in order to understand the experience, knowledge, and perceptions of health professionals treating SBE. In the US, in-depth interviews were performed with emergency physicians from January 2020 to March 2020. In BR, focus group discussions were conducted with health professionals from community health centers at the end of June 2021. The focus group discussions (BR) were originally analyzed through an inductive thematic analysis approach. We conducted a secondary qualitative analysis in which this codebook was then applied to the interviews (US) in a deductive content analysis. The analysis concluded in August 2022. Brazil participants were physicians (n=5) or nurses (n=20) from three municipalities in the State of Amazonas with an average of three years of professional experience. US participants were emergency physicians (n=16) with an average of 15 years of professional experience. Four main themes emerged: 1) barriers to adequate care on the patient and/or community side and 2) on the health system side, 3) perceived considerations for how to address SBE, and 4) identified needs for improving care. There were 25 subthemes within the four themes. These subthemes were largely the same across the Brazil and US data, but the rationale and content within each shared subtheme varied significantly. For example, the subtheme "role of health professionals in improving care" extended across Brazil and the US. Brazil emphasized the need for task-shifting and -sharing amongst health care disciplines, whereas the US suggested specialized approaches geared toward increasing access to toxicologists and other referral resources. Despite similar core barriers to adequate snakebite envenoming care and factors to consider when trying to improve care delivery, health professionals in different health systems and sociocultural contexts identified different needs. Accounting for, and understanding, these differences is crucial to the success of initiatives intended to strengthen snakebite envenoming care. Implementation science efforts, with explicit health professional input, should be applied to develop new and/or adapt existing evidence-based treatments and practices for SBE.

A generalized framework for estimating snakebite underreporting using statistical models: A study in Colombia

BACKGROUND

Snakebite envenoming is a neglected tropical disease affecting deprived populations, and its burden is underestimated in some regions where patients prefer using traditional medicine, case reporting systems are deficient, or health systems are inaccessible to at-risk populations. Thus, the development of strategies to optimize disease management is a major challenge. We propose a framework that can be used to estimate total snakebite incidence at a fine political scale.

METHODOLOGY/PRINCIPAL FINDINGS

First, we generated fine-scale snakebite risk maps based on the distribution of venomous snakes in Colombia. We then used a generalized mixed-effect model that estimates total snakebite incidence based on risk maps, poverty, and travel time to the nearest medical center. Finally, we calibrated our model with snakebite data in Colombia from 2010 to 2019 using the Markov-chain-Monte-Carlo algorithm. Our results suggest that 10.19% of total snakebite cases (532.26 yearly envenomings) are not reported and these snakebite victims do not seek medical attention, and that populations in the Orinoco and Amazonian regions are the most at-risk and show the highest percentage of underreporting. We also found that variables such as precipitation of the driest month and mean temperature of the warmest quarter influences the suitability of environments for venomous snakes rather than absolute temperature or rainfall.

CONCLUSIONS/SIGNIFICANCE

Our framework permits snakebite underreporting to be estimated using data on snakebite incidence and surveillance, presence locations for the most medically significant venomous snake species, and openly available information on population size, poverty, climate, land cover, roads, and the locations of medical centers. Thus, our algorithm could be used in other countries to estimate total snakebite incidence and improve disease management strategies; however, this framework does not serve as a replacement for a surveillance system, which should be made a priority in countries facing similar public health challenges.

Deadly and venomous Lonomia caterpillars are more than the two usual suspects

Caterpillars of the Neotropical genus Lonomia (Lepidoptera: Saturniidae) are responsible for some fatal envenomation of humans in South America inducing hemostatic disturbances in patients upon skin contact with the caterpillars' spines. Currently, only two species have been reported to cause hemorrhagic syndromes in humans: Lonomia achelous and Lonomia obliqua. However, species identifications have remained largely unchallenged despite improved knowledge of venom diversity and growing evidence that the taxonomy used over past decades misrepresents and underestimates species diversity. Here, we revisit the taxonomic diversity and distribution of Lonomia species using the most extensive dataset assembled to date, combining DNA barcodes, morphological comparisons, and geographical information. Considering new evidence for seven undescribed species as well as three newly proposed nomenclatural changes, our integrative approach leads to the recognition of 60 species, of which seven are known or strongly suspected to cause severe envenomation in humans. From a newly compiled synthesis of epidemiological data, we also examine the consequences of our results for understanding Lonomia envenomation risks and call for further investigations of other species' venom activities. This is required and necessary to improve alertness in areas at risk, and to define adequate treatment strategies for envenomed patients, including performing species identification and assessing the efficacy of anti-Lonomia serums against a broader diversity of species.

The secretory phenotypes of envenomed cells: Insights into venom cytotoxicity

Snake envenomation is listed as Category A Neglected Tropical Diseases (NTD) by World Health Organization, indicates a severe public health problem. The global figures for envenomation cases are estimated to be more than 1.8 million annually. Even if the affected victims survive the envenomation, they might suffer from permanent morbidity due to local envenomation. One of the most prominent local envenomation is dermonecrosis. Dermonecrosis is a pathophysiological outcome of envenomation that often causes disability in the victims due to surgical amputations, deformities, contracture, and chronic ulceration. The key venom toxins associated with this local symptom are mainly attributed to substantial levels of enzymatic and non-enzymatic toxins as well as their possible synergistic actions. Despite so, the severity of the local tissue damage is based on macroscopic observation of the bite areas. Furthermore, limited knowledge is known about the key biomarkers involved in the pathogenesis of dermonecrosis. The current immunotherapy with antivenom is also ineffective against dermonecrosis. These local effects eventually end up as sequelae. There is also a global shortage of toxins-targeted therapeutics attributed to inadequate knowledge of the actual molecular mechanisms of cytotoxicity. This chapter discusses the characterization of secretory phenotypes of dermonecrosis as an advanced tool to indicate its severity and pathogenesis in envenomation. Altogether, the secretory phenotypes of envenomed cells and tissues represent the precise characteristics of dermonecrosis caused by venom toxins.

Current situation of snakebites envenomation in the Neotropics: Biotechnology, a versatile tool in the production of antivenoms

Snakebite envenomation is a neglected tropical disease that affects millions of people around the world with a great impact on health and the economy. Unfortunately, public health programs do not include this kind of disease as a priority in their social programs. Cases of snakebite envenomations in the Neotropics are inaccurate due to inadequate disease management from medical records to the choice of treatments. Victims of snakebite envenomation are primarily found in impoverished agricultural areas where remote conditions limit the availability of antivenom. Antivenom serum is the only Food and Drug Administration-approved treatment used up to date. However, it has several disadvantages in terms of safety and effectiveness. This review provides a comprehensive insight dealing with the current epidemiological status of snakebites in the Neotropics and technologies employed in antivenom production. Also, modern biotechnological tools such as transcriptomic, proteomic, immunogenic, high-density peptide microarray and epitope mapping are highlighted for producing new-generation antivenom sera. These results allow us to propose strategic solutions in the Public Health Sector for managing this disease. Keywords: antivenom, biotechnology, neglected tropical disease, omics, recombinant antibody.

Preliminary assessment of antivenom availability and management in the public health system of Costa Rica: An analysis based on a survey to pharmacists in public health facilities

Availability and accessibility of safe and effective antivenoms are key elements for the successful treatment of snakebite envenoming (SBE). This study provides a preliminary analysis on the way antivenoms are managed by the public health system in Costa Rica and on the role played by pharmacists in the overall management of antivenoms. This was an observational, cross-sectional study based on an online survey sent to pharmacists working at Caja Costarricense de Seguro Social (Costa Rican Social Security System; CCSS) in different locations in Costa Rica. Characteristics and location of health facilities, as well as antivenom availability and management details, were analyzed. Responses from a total of 96 pharmacists, corresponding to 55 different healthcare facilities, were included in this study. Most respondents worked at pharmacies located in urban communities (69.0%) and in the secondary level of care, which includes clinics, and regional and peripheral hospitals (55.2%). Overall, participants reported antivenom availability at all levels of care and in centers having various operating schedules, although they were not available in some facilities in regions where SBE is uncommon or do not attend SBE cases because of the proximity of more complex health centers. On average, the stocks of anticoral and polyvalent antivenoms per health facility were compatible with the dose of antivenom required for treating a SBE case. More than half of participants reported knowing the availability of protocols for the management of SBE and the correct use of antivenom at their healthcare facilities. Of the total respondents, 49% agreed on possessing all the resources needed for the correct management of these medicines at their facilities, and 65.6% indicated that they know the procedures for antivenom storage and management. Our findings provide a first description of the availability of antivenoms in the public health system of Costa Rica, including the primary care level. Results also underscore the perceived role of participating pharmacists in the management of these life-saving drugs and the need to improve their knowledge on this topic.

Long-term health effects perceived by snakebite patients in rural Sri Lanka: A cohort study

The acute effects of snakebite are often emphasized, with less information on long-term effects. We aimed to describe the long-term health effects perceived by patients followed up after confirmed snakebites. Two groups of snakebite patients (>18y) from the Anuradhapura snakebite cohort were reviewed: Group I had a snakebite during August 2013-October 2014 and was reviewed after 4 years, and group II had a snakebite during May 2017-August 2018, and was reviewed after one year. Patients were invited by telephone, by sending letters, or doing home visits, including 199 of 736 patients (27%) discharged alive from group I and 168 of 438 patients (38%) from group II, a total of 367 followed up. Health effects were categorised as musculoskeletal, impact on daily life, and medically unexplained. Health issues were attributed to snakebite in 107/199 patients (54%) from group I and 55/168 patients (33%) from group II, suggesting the proportion with health issues increases with time. Sixteen patients (all viperine bites) had permanent musculoskeletal problems, none with a significant functional disability affecting daily routine. 217/367 reported being more vigilant about snakes while working outdoors, but only 21/367 were using protective footwear at review. Of 275 farmers reviewed, only six (2%) had restricted farming activities due to fear of snakebite, and only one stopped farming. 104/199 (52%) of group I and 42/168 (25%) of group II attributed non-specific symptoms (fatigue, body aches, pain, visual impairment) and/or oral cavity-related symptoms (avulsed teeth, loose teeth, receding gums) to the snakebite, which cannot be explained medically. In multivariate logistic regression, farming, type of snake, antivenom administration, and time since snakebite were associated with medically unexplained symptoms. The latter suggests medically unexplained effects increased with time. Based on two groups of snakebite patients reviewed one and four years post-bite, we show that long-term musculoskeletal disabilities are uncommon and not severe in snakebite survivors in rural Sri Lanka. However, a large portion of patients complain of various non-specific general and oral symptoms, not explainable based on the known pathophysiology of snakebite. These perceived effects of snakebite were more common in patients with systemic envenoming, and were more frequent the longer the time post-bite.

Generation of Multivalent Nanobody-Based Proteins with Improved Neutralization of Long α-Neurotoxins from Elapid Snakes

Recombinantly produced biotherapeutics hold promise for improving the current standard of care for snakebite envenoming over conventional serotherapy. Nanobodies have performed well in the clinic, and in the context of antivenom, they have shown the ability to neutralize long α-neurotoxins in vivo. Here, we showcase a protein engineering approach to increase the valence and hydrodynamic size of neutralizing nanobodies raised against a long α-neurotoxin (α-cobratoxin) from the venom of the monocled cobraNaja kaouthia. Based on the p53 tetramerization domain, a panel of anti-α-cobratoxin nanobody-p53 fusion proteins, termed Quads, were produced with different valences, inclusion or exclusion of Fc regions for endosomal recycling purposes, hydrodynamic sizes, and spatial arrangements, comprising up to 16 binding sites. Measurements of binding affinity and stoichiometry showed that the nanobody binding affinity was retained when incorporated into the Quad scaffold, and all nanobody domains were accessible for toxin binding, subsequently displaying increased blocking potency in vitro compared to the monomeric format. Moreover, functional assessment using automated patch-clamp assays demonstrated that the nanobody and Quads displayed neutralizing effects against long α-neurotoxins from both N. kaouthia and the forest cobra N. melanoleuca. This engineering approach offers a means of altering the valence, endosomal recyclability, and hydrodynamic size of existing nanobody-based therapeutics in a simple plug-and-play fashion and can thus serve as a technology for researchers tailoring therapeutic properties for improved neutralization of soluble targets such as snake toxins.

Recovery from the Neuroparalysis Caused by the Micrurus nigrocinctus Venom Is Accelerated by an Agonist of the CXCR4 Receptor

Snake envenoming is a major but neglected human disease in tropical and subtropical regions. Among venomous snakes in the Americas, coral snakes of the genus Micrurus are particularly dangerous because they cause a peripheral neuroparalysis that can persist for many days or, in severe cases, progress to death. Ventilatory support and the use of snake species-specific antivenoms may prevent death from respiratory paralysis in most cases. However, there is a general consensus that additional and non-expensive treatments that can be delivered even long after the snake bite are needed. Neurotoxic degeneration of peripheral motor neurons activates pro-regenerative intercellular signaling programs, the greatest of which consist of the chemokine CXCL12α, produced by perisynaptic Schwann cells, which act on the CXCR4 receptor expressed on damaged neuronal axons. We recently found that the CXCR4 agonist NUCC-390 promotes axonal growth. Here, we show that the venom of the highly neurotoxic snake Micrurus nigrocinctus causes a complete degeneration of motor axon terminals of the soleus muscle, followed by functional regeneration whose time course is greatly accelerated by NUCC-390. These results suggest that NUCC-390 is a potential candidate for treating human patients envenomed by Micrurus nigrocinctus as well as other neurotoxic Micrurus spp. in order to improve the recovery of normal neuromuscular physiology, thus reducing the mortality and hospital costs of envenoming.

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.

Medical Management after Lancehead Snakebite in North Amazon: A Case Report of Long-Term Disability

Snakebites are a major public health problem in indigenous communities in Brazil, leading to acute local and systemic damage with resulting deficiencies. Long-term musculoskeletal disabilities related to snakebites have been a neglected area of research. Bothrops (lancehead) snakes are responsible for most of the permanent sequelae related to snakebites in Latin America. Here, we present a case report of a 32-year-old male indigenous patient who was envenomed by a Bothrops species. The patient was clinically followed for a period of approximately 2 years and 6 months, during which time he experienced a loss of musculoskeletal tissue and required several medical procedures such as debridement, tissue reconstruction, and physical therapy, which resulted in a recovery of mobility, though with a permanent sequelae in gait. This case report shows how snakebites have a significant impact on health systems, as victims require physiotherapy, plastic surgery, and orthopedics services, as well as social support for reintegration into their local communities.

Development of a Monoclonal scFv against Cytotoxin to Neutralize Cytolytic Activity Induced by Naja atra Venom on Myoblast C2C12 Cells

The Taiwanese cobra, Naja atra, is a clinically significant species of snake observed in the wild in Taiwan. Victims bitten by N. atra usually experience severe pain and local tissue necrosis. Although antivenom is available for treatment of cobra envenomation, its neutralization potency against cobra-induced necrosis is weak, with more than 60% of cobra envenoming patients developing tissue necrosis after antivenom administration. The present study found that cytotoxin (CTX) is a key component of N. atra venom responsible for cytotoxicity against myoblast cells. Anti-CTX IgY was generated in hens, and the spleens of these hens were used to construct libraries for the development of single chain variable fragments (scFv). Two anti-CTX scFv, S1 and 2S7, were selected using phage display technology and biopanning. Both polyclonal IgY and monoclonal scFv S1 reacted specifically with CTX in cobra venom. In a cell model assay, the CTX-induced cytolytic effect was inhibited only by monoclonal scFv S1, not by polyclonal IgY. Moreover, the neutralization potency of scFv S1 was about 3.8 mg/mg, approximately three times higher than that of conventional freeze-dried neurotoxic antivenom (FNAV). Collectively, these results suggest that scFv S1 can effectively neutralize CTX-induced cytotoxicity and, when combined with currently available antivenom, can improve the potency of the latter, thereby preventing tissue damage induced by cobra envenoming.

Protective effects of novel diazepinone derivatives in snake venom induced sterile inflammation in experimental animals

Snake envenomation leads to the formation of damage-associated molecular patterns (DAMPs), which are mediated by endogenous intracellular molecules. These are recognized by pattern-recognition receptors (PRRs) and can induce sterile inflammation.

AIMS

In the present study, we aim at understanding the mechanisms involved in DAMPs induced sterile inflammation to unravel the novel therapeutic strategies for treating snake bites. The potential of benzodiazepinone derivatives to act against snake venom induced inflammation has been explored in the present investigation.

MAIN METHODS

Three compounds VA 17, VA 43 and PA 03 were taken from our library of synthetic compounds. Oxidative stress markers such as lipid peroxidation, superoxide and nitric oxide were measured along with the analysis of DAMPs (IL6, HMGB1, vWF, S100b and HSP70). These compounds have been docked using molecular docking against the snake venom PLA₂ structure (PDB code: 1OXL).

KEY FINDINGS

The compounds have been found to effectively neutralize viper and cobra venoms induced lethal activity both ex vivo and in vivo. The compounds have also neutralized the viper venom induced hemorrhagic, coagulant, anticoagulant reactions as well as inflammation. The fold of protection have always been found to be higher in case of ex vivo than in in vivo. These compounds have neutralized the venom induced DAMPs as exhibited by IL6, HMGB1, vWF, S100b and HSP70. The fold of neutralization is found to be higher in VA 43.

SIGNIFICANCE

The identified compounds could be used as potential candidates for developing treatment of snakebites in areas where antiserums are not yet available.

Synthetic antibodies block receptor binding and current-inhibiting effects of α-cobratoxin from Naja kaouthia

Each year, thousands of people fall victim to envenomings caused by cobras. These incidents often result in death due to paralysis caused by α-neurotoxins from the three-finger toxin (3FTx) family, which are abundant in elapid venoms. Due to their small size, 3FTxs are among the snake toxins that are most poorly neutralized by current antivenoms, which are based on polyclonal antibodies of equine or ovine origin. While antivenoms have saved countless lives since their development in the late 18th century, an opportunity now exists to improve snakebite envenoming therapy via the application of new biotechnological methods, particularly by developing monoclonal antibodies against poorly neutralized α-neurotoxins. Here, we describe the use of phage-displayed synthetic antibody libraries and the development and characterization of six synthetic antibodies built on a human IgG framework and developed against α-cobratoxin - the most abundant long-chain α-neurotoxin from Naja kaouthia venom. The synthetic antibodies exhibited sub-nanomolar affinities to α-cobratoxin and neutralized the curare-mimetic effect of the toxin in vitro. These results demonstrate that phage display technology based on synthetic repertoires can be used to rapidly develop human antibodies with drug-grade potencies as inhibitors of venom toxins.

Assessment of clinico- epidemiological profile of snakebite cases

The problem of snakebites has been persistently neglected by public health personnel, clinicians and policy makers even though its social and economic impact are wide‑spread. The present study was conducted to assess clinico- epidemiological profile of snakebite cases at BBMCH, Balangir, Odisha. 86 cases of snake bites of both genders was recorded. Parameters regarding sociodemographic profile, time and site of the bite, presenting complaints and time interval between snakebite and receiving medical treatment was recorded. Out of 86, males were 56 and females were 30. Common symptoms were local bleeding in 52, pain in 46, swelling in 51, diplopia in 22, hematuria in 34, abdominal pain in 68, vomiting in 76 and syncope in 24. The difference was significant (P< 0.05). The site involved was lower limb in 48 and upper limb & chest in 38. Time of presentation was <24 hours in 52 and >24 hours in 34. Type of snake was cobra in 25, python in 27, viper in 18 and Krait in 16 cases. The difference was significant (P< 0.05). Common symptoms were local bleeding, pain, swelling, diplopia, hematuria, abdominal pain, vomiting and syncope.

Use of geospatial analyses to address snakebite hotspots in mid-northern Brazil - A direction to health planning in shortfall biodiversity knowledge areas

Knowing the distribution of venomous snakes of medical importance is essential to identify areas at risk for snakebites. Thus, we used an integrative approach based on the application of geographic distribution data of venomous snakes, species distribution modeling (SDM), spatial organization of snakebites, and information on human population density for mapping the potential distribution of snakes and identifying areas at risk of snakebites in the state of Maranhão (mid-northern Brazil). From a compiled a database of venomous snake records deposited in biological collections and the literature, we predict the potential distribution of venomous snakes in Maranhão, a state whose diversity and geographic distribution of venomous snake species are poorly known. With this, we constructed potential distribution maps for each venomous snake species with at least one occurrence record within state boundaries, as well as generalized maps by family (Viperidae and Elapidae) and the total number of venomous snakes in Maranhão State. We also obtained data on the number of snakebites recorded in each municipality of Maranhão over a decade (2009-2019) and we ran a Generalized Linear Model to test for relationships between the number of venomous snakebites, the area of occurrence of snakes, and human population density. We obtained 1046 records of venomous snake species for Maranhão, represented by 17 viperid and elapid species. Most of the records were from Viperidae (mostly Bothrops atrox and B. marajoensis) and were concentrated mainly in the Amazonia of the northern portion of the state. The models showed accurate predictive performance for all modeled species. The entire area of Maranhão exhibits environmental conditions for the occurrence of venomous snakes, with higher suitability indices in the northern region, in the Amazon rainforest. The number of snakebites was positively correlated with high-risk areas (i.e., greater distribution of venomous snakes) and human population density. Our study is a pioneer in using species distribution modeling in mid-northern Brazil to address the scarcity of data on snakebite-causing species, directly contributing to the theme of neglected tropical diseases of the World Health Organization.

Profiling the Murine Acute Phase and Inflammatory Responses to African Snake Venom: An Approach to Inform Acute Snakebite Pathology

Snake envenoming causes rapid systemic and local effects that often result in fatal or long-term disability outcomes. It seems likely that acute phase and inflammatory responses contribute to these haemorrhagic, coagulopathic, neurotoxic, nephrotoxic and local tissue destructive pathologies. However, the contributory role of acute phase/inflammatory responses to envenoming is under-researched and poorly understood—particularly for envenoming by sub-Saharan African venomous snakes. To provide data to help guide future studies of human patients, and to explore the rationale for adjunct anti-inflammatory medication, here we used an in vivo murine model to systematically assess acute phase and inflammatory responses of mice to ten African snake venoms. In addition to investigating snake species-specific effects of venom on the cardiovascular system and other key organs and tissues, we examined the response to intravascular envenoming by acute phase reactants, including serum amyloid A, P-selectin and haptoglobin, and several cytokines. Venoms of the spitting (Naja nigricollis) and forest (N. melanoleuca) cobras resulted in higher acute phase and inflammatory responses than venoms from the other cobras, mambas and vipers tested. Naja nigricollis venom also stimulated a 100-fold increase in systemic interleukin 6. Thin blood films from venom-treated mice revealed species-specific changes in red blood cell morphology, indicative of membrane abnormalities and functional damage, lymphopenia and neutrophil leukocytosis. Our ex vivo assays with healthy human blood treated with these venoms identified that N. nigricollis venom induced marked levels of haemolysis and platelet aggregation. We conclude that African snake venoms stimulate very diverse responses in this mouse model of acute systemic envenoming, and that venoms of the African cobras N. nigricollis and N. melanoleuca, in particular, cause marked inflammatory and non-specific acute phase responses. We also report that several African snake venoms cause haemolytic changes. These findings emphasise the importance of understanding acute responses to envenoming, and that further research in this area may facilitate new diagnostic and treatment approaches, which in turn may lead to better clinical outcomes for snakebite patients.

Treatment outcomes among snakebite patients in north-west Ethiopia-A retrospective analysis

BACKGROUND

Millions of people are bitten by venomous snakes annually, causing high mortality and disability, but the true burden of this neglected health issue remains unknown. Since 2015, Médecins Sans Frontières has been treating snakebite patients in a field hospital in north-west Ethiopia. Due to the poor market situation for effective and safe antivenoms for Sub-Saharan Africa, preferred antivenom was not always available, forcing changes in choice of antivenom used. This study describes treatment outcomes and the effectiveness and safety of different antivenoms used.

METHODOLOGY / PRINCIPAL FINDINGS

This retrospective observational study included 781 snakebite patients presenting at the field hospital between 2015 and 2019. Adjusted odds ratios, 95%-CI and p-values were used to compare the treatment outcome of patients treated with Fav-Afrique (n = 149), VacSera (n = 164), and EchiTAb-PLUS-ICP (n = 156) antivenom, and to identify the risk of adverse reactions for each antivenom. Whereas only incidental snakebite cases presented before 2015, after treatment was made available, cases rapidly increased to 1,431 in 2019. Envenomation was mainly attributed to North East African saw-scaled viper (Echis pyramidum) and puff adder (Bitis arietans). Patients treated with VacSera antivenom showed lower chance of uncomplicated treatment outcome (74.4%) compared to Fav-Afrique (93.2%) and EchiTAb-PLUS-ICP (90.4%). VacSera and EchiTAb-PLUS-ICP were associated with 16- and 6-fold adjusted odds of treatment reaction compared to Fav-Afrique, respectively, and VacSera was weakly associated with higher odds of death.

CONCLUSIONS / SIGNIFICANCE

Snakebite frequency is grossly underreported unless treatment options are available. Although EchiTAb-PLUS-ICP showed favorable outcomes in this retrospective analysis, prospective randomized trials are needed to evaluate the effectiveness and safety of the most promising antivenoms for Sub-Saharan Africa. Structural investment in sustained production and supply of antivenom is urgently needed.

A study on the clinical, epidemiological profile and the outcome of the snake bite victims in kashmir valley

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A phase IV, prospective, observational study of the clinical safety of snake antivenoms

Snake envenoming is a neglected tropical disease that affects more than 2.7 million people worldwide. The treatment is based on the administration of antivenom composed of heterologous immunoglobulins, species-specific therapy involving the possibility of adverse reactions due to activation of the immune system. Considering the scarcity of prospective studies evaluating the safety of snake antivenoms, this study aimed to describe and characterize adverse events after antivenom infusion in an observational, prospective, single-centre investigation conducted in a referral centre in Brazil. A total of 47 victims of snake envenoming were included in the study, who were mostly men (75%), with ages ranging from 2 to 83 years. Twenty-two participants (47%) presented manifestations compatible with infusion-related reactions (IRRs) during or up to two hours after F(ab')2 heterologous immunoglobulin infusion. The most common clinical manifestation related to the infusion was a diffuse cutaneous rash (82%), followed by respiratory manifestations (46%) and facial swelling (23%). In four cases (9%), IRR were considered serious adverse events (SAE), characterized by haemodynamic instability, airway obstruction or hypoxia. Only one patient developed symptoms compatible with serum sickness. Although almost half of the patients treated with antivenom sera experienced IRRs, the SAE rate was 9%; in all cases, the adverse reaction was reversible by using supportive treatment, and there were no deaths. The results have shown that there is much to improve in the antivenom production process to obtain a more purified and specific product. Even so, a timely antivenom serum administration managed by well-trained health teams is safe and prevents complications after snake-related accidents.