Access to antivenoms in the developing world: A multidisciplinary analysis

Experimental production and efficacy testing of mono-specific antibodies against the venom of carpet viper (Echis ocellatus) from savannah Nigeria

Echis ocellatus is one of the commonest snakes responsible for envenomation in Nigeria. Antivenom is the only effective treatment, but the country suffers from a limited supply of effective antivenom. This study therefore aimed to explore the feasibility of effective, mono-specific antibodies production through immunization in rabbits using the venom of Echis ocellatus from Nigeria. The World Health Organization guide on antivenom production was employed in the immunization and the resultant antibodies were purified using protein A agarose column chromatography. Antibody titer reached a high plateau by 2-month immunization, and SDS PAGE of the sera suggests the presence of intact immunoglobulins accompanied with the heavy (50 kDa) and light (25 kDa) chains. The venom has an intravenous LD50 of 0.35 mg/kg in mice, and the venom lethality at a challenge dose of 2 LD50 was effectively neutralized by the antibodies with a potency value of 0.83 mg venom per g antibodies. The antibodies also neutralized the procoagulant activity of the venom with an effective dose (ED) of 13 ± 0.66 μl, supporting its use for hemotoxic envenomation. The study establishes the feasibility of developing effective, mono-specific antibodies against the Nigerian Carpet viper.

Inequalities in access to antivenom: An ethical issue in the management of snakebite envenoming

Snakebite envenoming is a high-priority neglected tropical disease and antivenom is the cornerstone of treatment. Antivenom is listed among essential medicines and its access must be considered as a human right. Despite resolutions from various international organizations including the WHO, antivenom remains unavailable, unaffordable, and sometimes not targeted against the specific snake involved. Also, despite an expanding global antivenom market, some manufacturers have stopped production due to a lack of profits. However, justice and equitable access to care according to medical needs are among the four pillars of medical ethics. Overall, snakebite envenoming is a typical example of social and ethnic inequity in medicine. It is imperative that this issue be addressed from an ethical standpoint and that government laboratories take the lead in antivenom production.

Preclinical testing of expired antivenoms and its uses in real-world experience: a systematic review

INTRODUCTION

Limited access to antivenoms is a global challenge in treating snakebite envenoming. In emergency situations where non-expired antivenoms are not readily available, expired antivenoms may be used to save lives with the risk of deteriorating quality, efficacy and safety. Therefore, we aimed to systematically review and summarise the sparse preclinical evidence of neutralising efficacy of expired antivenoms and real-world experience of using expired antivenoms in humans.

METHODS

We searched for articles published until 1 March 2023 in PubMed, Scopus, Web of Science and Embase. Studies demonstrating the preclinical studies evaluating expired antivenoms or studies describing the real-world experience of using expired antivenoms were included. Narrative synthesis was applied to summarise the evidence of expired antivenoms.

RESULTS

Fifteen studies were included. Ten were preclinical studies and five were real-world experiences of using expired antivenoms in humans. The expired duration of antivenoms in the included studies ranged from 2 months to 20 years. The quality of expired antivenoms was evaluated in one study, and they met the standard quality tests. Five studies demonstrated that the expired antivenoms' immunological concentration and venom-binding activity were comparable to non-expired ones but could gradually deteriorate after expiration. Studies consistently exhibited that expired antivenoms, compared with non-expired antivenoms, were effective when stored in proper storage conditions. The safety profile of using expired antivenoms was reported in two included studies. However, it was inconclusive due to limited information.

CONCLUSION

Even though the quality and efficacy of expired antivenoms are comparable to non-expired antivenoms in preclinical studies, the information is limited in terms of real-world experiences of using expired antivenoms and their safety. Therefore, the use of expired antivenoms may be generally inconclusive due to scarce data. Further investigations may be needed to support the extension of antivenoms' expiration date according to their potential efficacy after expiration.

Bridges between two medical realities: Perspectives of Indigenous medical and nursing students on snakebite care in the Brazilian Amazon

In the Brazilian Amazon, snakebite envenomations (SBEs) disproportionately affect Indigenous populations, and have a significantly higher incidence and lethality than in non-Indigenous populations. This qualitative study describes the Indigenous and biomedical healthcare domains for SBE care from the perspective of the Indigenous medical and nursing students in Manaus, Western Brazilian Amazon. In-depth interviews were conducted with five Indigenous students from the Amazonas State University, between January and December 2021. The interviews were analyzed using inductive content analysis. We organized an explanatory model with five themes: (1) participants' identities; (2) causality levels in Indigenous and biomedical systems; (3) therapeutic itineraries in Indigenous and biomedical systems; (4) ideological implications of adding biomedical devices to Indigenous healing systems; and (5) therapeutic failure in and efficacy of Indigenous and biomedical systems. From a noncolonial perspective and seeking to increase the quality and acceptability of health care for the Indigenous populations of the Brazilian Amazon, the training of Indigenous health professionals presents itself as a promising strategy. For this goal, universities should serve as empowering settings for Indigenous health students that support them in their growth and development, raise their awareness of injustice, and catalyze change toward a culturally adapted and effective service for the users.

Antitoxin nanoparticles: design considerations, functional mechanisms, and applications in toxin neutralization

The application of nanotechnology has significantly advanced the development of novel platforms that enhance disease treatment and diagnosis. A key innovation in this field is the creation of antitoxin nanoparticles (ATNs), designed to address toxin exposure. These precision-engineered nanosystems have unique physicochemical properties and selective binding capabilities, allowing them to effectively capture and neutralize toxins from various biological, chemical, and environmental sources. In this review, we thoroughly examine their therapeutic and diagnostic potential for managing toxin-related challenges. We also explore recent advancements and offer critical insights into the design and clinical implementation of ATNs.

The geographical distribution of scorpions, implication of venom toxins, envenomation, and potential therapeutics in Southern and Northern Africa

Scorpions are predatory arachnids whose venomous sting primarily affects people in tropical and subtropical regions. Most scorpion stings can only cause localized pain without severe envenomation. Less than one-third of the stings cause systemic envenoming and possibly lead to death. About 350,000 scorpion stings in Northern Africa are recorded yearly, resulting in about 810 deaths. In Eastern/Southern Africa, there are about 79,000 stings recorded yearly, resulting in 245 deaths. Farmers and those living in poverty-stricken areas are among the most vulnerable to getting stung by scorpions. However, compared to adults, children are at greater risk of severe envenomation. Scorpion venom is made up of complex mixtures dominated by peptides and proteins that confer its potency and toxicity. These venom toxins have intra- and interspecies variations associated with the scorpion's habitat, sex, diet, and age. These variations alter the activity of antivenoms used to treat scorpion sting envenomation. Thus, the study of the proteome composition of medically important scorpion venoms needs to be scaled up along their geographical distribution and contributions to envenomation in Southern and Northern Africa. This will help the production of safer, more effective, and broad-spectrum antivenoms within these regions. Here, we review the clinical implications of scorpion sting envenomation in Southern and Northern Africa. We further highlight the compositions of scorpion venoms and tools used in scorpion venomics. We discuss current antivenoms used against scorpion sting envenomation and suggestions for future production of better antivenoms or alternatives. Finally, we discuss the therapeutic properties of scorpion venom.

Snakebite incidence and healthcare-seeking behaviors in Eastern Province, Rwanda: A cross-sectional study

BACKGROUND

Snakebite envenoming (SBE) is a potentially life-threatening event that can lead to severe physical, mental, and economic hardships, particularly in under-resourced regions like sub-Saharan Africa. In Rwanda, there have been no epidemiological assessments of SBE to guide the Ministry of Health in its efforts to reduce the burden. This study had two main objectives: first, to estimate the incidence of snakebites across districts, and second, to describe formal versus informal healthcare seeking behaviors among snakebite victims in Eastern Province, Rwanda in 2020.

METHODOLOGY

This cross-sectional study utilized a cluster sampling approach, involving Community Health Workers (CHWs) who recorded snakebite cases across seven districts. The descriptive analysis considered sampling weights, and healthcare seeking behavior was assessed based on the type of care sought as the first point of treatment.

FINDINGS

The study surveyed 390,546 individuals across 763 villages and estimated a provincial annual incidence rate of 4.3 cases per 1,000 individuals. Incidence estimates ranged from 1.1 cases per 1,000 in Nyagatare to 9.1 cases per 1,000 individuals in Bugesera and Ngoma districts. Among the 2,545 cases recorded by CHWs, three resulted in deaths. Regarding healthcare-seeking behavior, 13% of snakebite victims (143 out of 1,098) initially consulted formal care providers (CHWs, health post/center, or hospital), while 87% sought informal care (family/friends, pharmacist, or traditional healer). Approximately half of the victims (583, 53.1%) reported severe symptoms. Unsafe practices included skin cutting/burning, tourniquet application, use of black stones, and venom extraction; only 24 cases (2.2%) received anti-venom.

CONCLUSIONS

This large-scale community-based assessment highlights variations in snakebite incidence between districts and confirms frequent involvement of traditional healers in management. Improving access to anti-venom and community education on the risks of ineffective practices, along with timely use of formal healthcare, are crucial. Collaboration between healthcare providers, traditional healers, community leaders, and policymakers is essential to implement targeted interventions for enhancing snakebite prevention and management strategies.

Snakebite Management: The Need of Reassessment, International Relations, and Effective Economic Measures to Reduce the Considerable SBE Burden

The sole treatment for snakebite envenomation (SBE), the anti-snake venom (ASV), suffers from considerable drawbacks, including side effects and limited species specificity. Additionally, despite its existence for more than a century, uniform availability of good quality ASV does not yet exist. The present review describes the journey of a SBE victim and highlights the global crisis of SBE management. A detailed analysis of the current ASV market has also been presented along with the worldwide snake distribution. The current production of country specific licensed ASV throughout the globe along with their manufacturers has been examined at the snake species level. Furthermore, a detailed analysis of on-ground situation of SBE management in antivenom manufacturing countries has been done using the most recent literature. Additionally, the export and import of different ASVs have been discussed in terms of procurement policies of individual countries, their shortcomings, along with the possible solution at the species level. It is interesting to note that in most countries, the existence of ASV is really either neglected or overstated, implying that it is there but unsuitable for use, or that it is not present but can be obtained from other countries. This highlights the urgent need of significant reassessment and international collaborations not just for development and production, but also for procurement, distribution, availability, and awareness. A PROMISE (Practical ROutes for Managing Indigenous Snakebite Envenoming) approach has also been introduced, offering simple, economical, and easy to adopt steps to efficiently alleviate the worldwide SBE burden.

Development and optimization of a DNA aptamer to delay β-bungarotoxin-induced lethality in a rodent model

Current treatment of snakebite relies on immunoglobulin-rich antivenoms. However, production of these antivenoms is complicated and costly. Aptamers - single-stranded DNAs or RNAs with specific folding structures that bind to specific target molecules - represent excellent alternatives or complements to antibody-based therapeutics. However, no studies have systematically assessed the feasibility of using aptamers to mitigate venom-induced toxicity in vivo. β-bungarotoxin is the predominant protein responsible for the toxicity of the venom of Bungarus multicinctus, a prominent venomous snake inhabiting Taiwan. In this study, we reported the screening and optimization of a DNA aptamer against β-bungarotoxin and tested its utility in a mouse model. After 14 rounds of directed evolution of ligands by exponential enrichment, an aptamer, called BB3, displaying remarkable binding affinity and specificity for β-bungarotoxin was obtained. Following structural prediction and point-modification experiments, BB3 underwent truncation and was modified with 2'-O-methylation and a 3'-inverted dT. This optimized aptamer showed sustained, high-affinity binding for β-bungarotoxin and exhibited remarkable nuclease resistance in plasma. Importantly, administration of this optimized aptamer extended the survival time of mice treated with a lethal dose of β-bungarotoxin. Collectively, our data provide a compelling illustration of the potential of aptamers as promising candidates for development of recombinant antivenom therapies.

An indigenously developed tele-ICU model to treat severe cases of envenomation in remote regions in India

In cases of severe envenomation due to snakebites, patients require antivenom, intensive care management, including respiratory support, haemodynamic monitoring and renal replacement therapy. Early recognition and treatment of complications such as acute kidney injury, rhabdomyolysis and coagulopathy are important to improve outcomes.Tele-ICU models can play a critical role in providing access to critical care expertise and nuanced support to remote healthcare facilities that may not have the necessary resources or expertise to manage complex cases of envenomation. With the help of telemedicine technology, remote intensivists can provide timely guidance on diagnosis and ongoing management, improving the quality of care and outcomes for patients. We discuss two patients in resource-constrained regions of India with severe envenomation who were managed with tele-ICU support.

African polyvalent antivenom can maintain pharmacological stability and ability to neutralise murine venom lethality for decades post-expiry: evidence for increasing antivenom shelf life to aid in alleviating chronic shortages

INTRODUCTION

Antivenom is a lifesaving medicine for treating snakebite envenoming, yet there has been a crisis in antivenom supply for many decades. Despite this, substantial quantities of antivenom stocks expire before use. This study has investigated whether expired antivenoms retain preclinical quality and efficacy, with the rationale that they could be used in emergency situations when in-date antivenom is unavailable.

METHODS

Using WHO guidelines and industry test requirements, we examined the in vitro stability and murine in vivo efficacy of eight batches of the sub-Saharan African antivenom, South African Institute for Medical Research polyvalent, that had expired at various times over a period of 30 years.

RESULTS

We demonstrate modest declines in immunochemical stability, with antivenoms older than 25 years having high levels of turbidity. In vitro preclinical analysis demonstrated all expired antivenoms retained immunological recognition of venom antigens and the ability to inhibit key toxin families. All expired antivenoms retained comparable in vivo preclinical efficacy in preventing the lethal effects of envenoming in mice versus three regionally and medically important venoms.

CONCLUSIONS

This study provides strong rationale for stakeholders, including manufacturers, regulators and health authorities, to explore the use of expired antivenom more broadly, to aid in alleviating critical shortages in antivenom supply in the short term and the extension of antivenom shelf life in the longer term.

Immunoreactivity and neutralization efficacy of Pakistani Viper Antivenom (PVAV) against venoms of Saw-scaled Vipers (Echis carinatus subspp.) and Western Russell's Vipers (Daboia russelii) from the Indian subcontinent

Snakebite envenoming (SBE) is a priority Neglected Tropical Disease listed by the World Health Organization. South Asia is heavily affected, and virtually all countries in the region import polyvalent antivenom products from India for clinical use. The imported antivenoms, however, have suboptimal effectiveness due to geographical venom variation. Recently, a domestic bivalent product, named Pakistani Viper Antivenom (PVAV) has been developed specifically for Pakistani vipers, Echis carinatus sochureki and Daboia russelii. As a bivalent viperid antivenom, it is unknown yet if PVAV exhibits higher immunological binding and neutralization activities against viper venoms from distant locales compared with polyvalent antivenoms manufactured in India. This study thus examined the preclinical efficacy of PVAV against venoms of Western Russell's Vipers and Saw-scaled Viper subspecies from selected locales in the Indian subcontinent. PVAV generally outperformed the commonly used VINS polyvalent antivenom (VPAV, manufactured in India) in binding toward venoms, and showed superior or comparable neutralization efficacy against the venom procoagulant and hemorrhagic effects of Saw-scaled Vipers as well as Russell's Vipers from Pakistan and Sri Lanka. Based on normalized potency values, PVAV is far more potent than VPAV in neutralizing the lethality of all viper venoms, except that of the Indian Russell's Viper. The study shows conserved antigenicity of toxins responsible for major toxicity across these viperid venoms, and suggests the feasible production of a viper-specific antivenom with higher potency and broader geographical utility for the region.

Towards better antivenoms: navigating the road to new types of snakebite envenoming therapies

Snakebite envenoming is a significant global health challenge, and for over a century, traditional plasma-derived antivenoms from hyperimmunized animals have been the primary treatment against this infliction. However, these antivenoms have several inherent limitations, including the risk of causing adverse reactions when administered to patients, batch-to-batch variation, and high production costs. To address these issues and improve treatment outcomes, the development of new types of antivenoms is crucial. During this development, key aspects such as improved clinical efficacy, enhanced safety profiles, and greater affordability should be in focus. To achieve these goals, modern biotechnological methods can be applied to the discovery and development of therapeutic agents that can neutralize medically important toxins from multiple snake species. This review highlights some of these agents, including monoclonal antibodies, nanobodies, and selected small molecules, that can achieve broad toxin neutralization, have favorable safety profiles, and can be produced on a large scale with standardized manufacturing processes. Considering the inherent strengths and limitations related to the pharmacokinetics of these different agents, a combination of them might be beneficial in the development of new types of antivenom products with improved therapeutic properties. While the implementation of new therapies requires time, it is foreseeable that the application of biotechnological advancements represents a promising trajectory toward the development of improved therapies for snakebite envenoming. As research and development continue to advance, these new products could emerge as the mainstay treatment in the future.

Considerations for the development of a field-based medical device for the administration of adjunctive therapies for snakebite envenoming

The timely administration of antivenom is the most effective method currently available to reduce the burden of snakebite envenoming (SBE), a neglected tropical disease that most often affects rural agricultural global populations. There is increasing interest in the development of adjunctive small molecule and biologic therapeutics that target the most problematic venom components to bridge the time-gap between initial SBE and the administration antivenom. Unique combinations of these therapeutics could provide relief from the toxic effects of regional groupings of medically relevant snake species. The application a PRISMA/PICO literature search methodology demonstrated an increasing interest in the rapid administration of therapies to improve patient symptoms and outcomes after SBE. Advice from expert interviews and considerations regarding the potential routes of therapy administration, anatomical bite location, and species-specific venom delivery have provided a framework to identify ideal metrics and potential hurdles for the development of a field-based medical device that could be used immediately after SBE to deliver adjunctive therapies. The use of subcutaneous (SC) or intramuscular (IM) injection were identified as potential routes of administration of both small molecule and biologic therapies. The development of a field-based medical device for the delivery of adjunctive SBE therapies presents unique challenges that will require a collaborative and transdisciplinary approach to be successful.

"I sold my towel and shoes to pay the traditional healer": Care-seeking costs and productivity losses among snakebite victims in Eastern Province, Rwanda

Snakebite envenomation (SBE) is endemic to sub-Saharan Africa and generally over-represented in rural, remote, and impoverished agricultural communities. While poverty is an established risk factor, little research has been done to investigate the economic consequences of SBE. This cross-sectional, quantitative study aimed to measure out-of-pocket spending and lost income when a household member was bitten by a snake. In 2020, 732 snakebite survivors from Eastern Province (Rwanda) agreed to complete a survey administered by telephone. The survey focused on participant demographics, income, direct medical and non-medical costs, care-seeking decisions, and lost work during convalescence. Our results suggested that patients incurred the highest mean expenses when they sought care from hospitals (11 307 RWF or 12 USD) or traditional healers (5 836 RWF or 6 USD) but that the highest maximum cost was incurred from traditional healers (300 000 RWF or 313 USD). Across all victims, the total amount paid to traditional healers (3.4 million RWF or 3 537 USD) was 4.7 times higher than all other care providers combined. On average, families lost 111 814 RWF (117 USD) per snakebite in direct treatment costs and indirect productivity losses. Many victims sought care from traditional healers despite being eligible for free medical care. Altogether, this study serves as a reminder of the serious physical and financial consequences associated with SBE and provides justification for new investments into SBE prevention and care.

An in vitro assay to investigate venom neurotoxin activity on muscle-type nicotinic acetylcholine receptor activation and for the discovery of toxin-inhibitory molecules

Snakebite envenoming is a neglected tropical disease that causes over 100,000 deaths annually. Envenomings result in variable pathologies, but systemic neurotoxicity is among the most serious and is currently only treated with difficult to access and variably efficacious commercial antivenoms. Venom-induced neurotoxicity is often caused by α-neurotoxins antagonising the muscle-type nicotinic acetylcholine receptor (nAChR), a ligand-gated ion channel. Discovery of therapeutics targeting α-neurotoxins is hampered by relying on binding assays that do not reveal restoration of receptor activity or more costly and/or lower throughput electrophysiology-based approaches. Here, we report the validation of a screening assay for nAChR activation using immortalised TE671 cells expressing the γ-subunit containing muscle-type nAChR and a fluorescent dye that reports changes in cell membrane potential. Assay validation using traditional nAChR agonists and antagonists, which either activate or block ion fluxes, was consistent with previous studies. We then characterised antagonism of the nAChR by a variety of elapid snake venoms that cause muscle paralysis in snakebite victims, before defining the toxin-inhibiting activities of commercial antivenoms, and new types of snakebite therapeutic candidates, namely monoclonal antibodies, decoy receptors, and small molecules. Our findings show robust evidence of assay uniformity across 96-well plates and highlight the amenability of this approach for the future discovery of new snakebite therapeutics via screening campaigns. The described assay therefore represents a useful first-step approach for identifying α-neurotoxins and their inhibitors in the context of snakebite envenoming, and it should provide wider value for studying modulators of nAChR activity from other sources.

Antivenom for sale? Availability and affordability of snakebite medicines across public and private health facilities in Rwanda

Antivenom is considered the safest and most effective treatment against snake envenomation (SBE); however, global shortages mean that many low-income countries struggle to meet demand. In Rwanda, chronic shortages of essential medicines are an important barrier to robust healthcare delivery and discourage snakebite victims from seeking hospital care. The aim of this retrospective, cross-sectional study was to evaluate the availability and affordability of commodities to treat SBE at hospitals and health centers. In total, our team interviewed pharmacy managers at 111 public and 31 private health facilities (N = 142) to complete a validated quantitative questionnaire, entering data electronically through KoBoCollect. Commodity prices were collected in 2023RWF and for the lowest cost item across any category. A commodity was considered affordable if a treatment regimen cost less than one day's wages, using the international poverty line to approximate a low-income worker's wages. Across all health facilities, mean availability of SBE commodities was relatively good (77.1%). Snake antivenom was only available at public hospitals and was concentrated in urban rather than rural areas. Two snake antivenom types were observed, one of which was not appropriate for treating envenomation by East African snakes. Overall, this meant that only 4.2% of facilities stocked safe and effective antivenom. Black stones, an ineffective traditional treatment, were sold by 5.6% of health providers. Moreover, antivenom did not meet the minimum threshold for affordability, costing on average 10 days of work for a single dose among uninsured individuals. Altogether, this study highlights serious performance gaps among pharmacies responsible for procuring and supplying SBE commodities and helps to explain the widespread belief that SBE treatment is unaffordable at hospitals and health centers. Urgent action is needed to ensure that all hospital and health center pharmacies located in high-risk areas stock appropriate antivenom and that re-stocking time for essential medicines is reduced.

Barriers and opportunities for improving management of snakebites: Perspectives of healthcare workers in Northern Uganda

BACKGROUND

Snakebites are a neglected public health problem that pose a significant burden on affected individuals and communities in many sub-Saharan African countries, including Uganda. However, the barriers and facilitators to snakebite management within healthcare settings are not as well understood and well-documented. The aim of this study was to explore the experiences and perspectives of healthcare workers involved in handling snakebite incidents at individual and health system levels in Arua and Gulu districts in Northern Uganda. We sought to understand how healthcare workers manage snakebite cases, what challenges they encounter, and what opportunities they perceive for improvement.

METHODS

We conducted a qualitative study using in-depth interviews with 18 healthcare workers from different cadres, seniority levels, and facility types. We used iterative thematic analysis to explore the management procedures, challenges, and opportunities for snakebite management. Using thematic analysis, we identified the overarching themes and subthemes related to snakebite management and associated barriers and opportunities.

RESULTS

The main barriers to snakebite management identified by healthcare workers were inadequate knowledge and skills; limited availability of antivenom; lack of protocols for snakebite management; delayed treatment-seeking for patients; and poor referral systems. The main opportunities for improvement were regular in-service training; increasing public education and awareness about snakebite prevention and management; and increased funding and research.

CONCLUSION

This study highlights the need for interventions to address the identified barriers while leveraging the existing opportunities to enhance snakebite management in Uganda. Specifically, we recommend the provision of regular training and support to healthcare workers, developing clinical guidelines, and improving the availability of antivenoms.

Compendium of medically important snakes, venom activity and clinical presentations in Ghana

BACKGROUND

Snake bite envenoming (SBE) is one neglected tropical disease that has not received the needed attention. The sequelae of burdensome disability and mortality impact the socioeconomic life of communities adversely with little documentation of SBE in health facility records in Ghana. This study details SBE and snake distribution, habits/habitats, type of venom expressed and clinical manifestations.

METHODOLOGY

We conducted a structured thematic desk review of peer reviewed papers, books and reports from repositories including PubMed, World Health Organization (WHO) and Women's & Children's Hospital (WCH) Clinical Toxinology Resources using bibliographic software EndNote and search engine Google Scholar with the following key words; snakes, medical importance, snake bites, venom and venom type, envenomation, symptoms and signs, vaccines, venom expenditure, strike behaviour and venom-metering + Ghana, West Africa, Africa, World. We also reviewed data from the District Health Information Management System (DHIMS) of the Ghana Health Service (GHS). Outcome variables were organized as follows: common name (s), species, habitat/habit, species-specific toxin, clinical manifestation, antivenom availability, WHO category.

FINDINGS

Snake bites and SBE were grouped by the activity of the expressed venom into neurotoxic, cardiotoxic, haemorrhagic, cytotoxic, myotoxic, nephrotoxic and procoagulants. Neurotoxic snake bites were largely due to elapids. Expressed venoms with cardiotoxic, haemorrhagic, nephrotoxic and procoagulant activities principally belonged to the family Viperidae. Snakes with venoms showing myotoxic activity were largely alien to Ghana and the West African sub-region. Venoms showing cytotoxic activity are expressed by a wide range of snakes though more prevalent among the Viperidae family. Snakes with neurotoxic and haemorrhagic venom activities are prevalent across all the agro-ecological zones in Ghana.

CONCLUSION/SIGNIFICANCE

Understanding the characteristics of snakes and their venoms is useful in the management of SBE. The distribution of snakes by their expressed venoms across the agro-ecological zones is also instructive to species identification and diagnosis of SBE.

Snake Antivenoms-Toward Better Understanding of the Administration Route

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

Availability, accessibility and use of antivenom for snakebite envenomation in Africa with proposed strategies to overcome the limitations

Africa remains one of the regions with the highest incident and burden of snakebite. The goal of the World Health Organization to halve the global burden of snakebite by 2030 can only be achieved if sub-optimal access to antivenoms in the most affected regions is addressed. We identified upstream, midstream, and downstream factors along the antivenom value chain that prevent access to antivenoms in the African region. We identified windows of opportunities that could be utilized to ensure availability, accessibility, and affordability for snakebite endemic populations in Africa. These include implementation of multicomponent strategies such as intensified advocacy, community engagement, healthcare worker trainings, and leveraging the institutional and governance structure provided by African governments to address the challenges identified.

Identifying high snakebite risk area under climate change for community education and antivenom distribution

Snakebite is one of the largest risks from wildlife, however little is known about venomous snake distribution, spatial variation in snakebite risk, potential changes in snakebite risk pattern due to climate change, and vulnerable human population. As a consequence, management and prevention of snakebite is hampered by this lack of information. Here we used habitat suitability modeling for 10 medically important venomous snakes to identify high snakebite risk area under climate change in Iran. We identified areas with high snakebite risk in Iran and showed that snakebite risk will increase in some parts of the country. Our results also revealed that mountainous areas (Zagros, Alborz, Kopet-Dagh mountains) will experience highest changes in species composition. We underline that in order to improve snakebite management, areas which were identified with high snakebite risk in Iran need to be prioritized for the distribution of antivenom medication and awareness rising programs among vulnerable human population.

Clinical aspects of snakebite envenoming and its treatment in low-resource settings

There is increasing recognition of the public health importance of snakebite envenoming. Worldwide annual incidence is likely to be 5 million bites, with mortality exceeding 150 000 deaths, and the resulting physical and psychological morbidity leads to substantial social and economic repercussions. Prevention through community education by trained health workers is the most effective and economically viable strategy for reducing risk of bites and envenoming. Clinical challenges to effective treatment are most substantial in rural areas of low-resource settings, where snakebites are most common. Classic skills of history taking, physical examination, and use of affordable point-of-care tests should be followed by monitoring of evolving local and systemic envenoming. Despite the profusion of new ideas for interventions, hyperimmune equine or ovine plasma-derived antivenoms remain the only specific treatment for snakebite envenoming. The enormous interspecies and intraspecies complexity and diversity of snake venoms, revealed by modern venomics, demands a radical redesign of many current antivenoms.

Snakebite envenoming at MSF: A decade of clinical challenges and antivenom access issues

The medical humanitarian organization Médecins Sans Frontières (MSF) provides medical care in more than 70 countries and admits more than 7000 cases of snakebite in its facilities each year. We describe our activities against snakebite in three African countries: Central African Republic, South Sudan and Ethiopia, in which different models of care have been developed. A standard protocol using two different antivenoms depending on the patient's syndrome has been introduced, and a simple blood coagulation test is performed to detect venom-induced coagulopathy. Other services, including surgery for necrotizing wounds, are offered in the facilities where MSF admits a large number of snakebite patients. All services, including provision of antivenom, are offered free-of-charge in MSF-supported facilities. Community-based activities focusing on preventive measures and prompt transport to hospital have been developed in a few MSF projects. The provision of quality care and treatment, including effective antivenoms, without out-of-pocket payments by the patients, probably explains why MSF has admitted an increasing number of snakebite victims over the last years. This model requires significant resources and monitoring, including regular training of healthcare workers on treatment protocols and a considerable budget for antivenom procurement.

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.

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.

Two snakebite antivenoms have potential to reduce Eswatini's dependency upon a single, increasingly unavailable product: Results of preclinical efficacy testing

BACKGROUND

Snakebite is a major public health concern in Eswatini, where treatment relies upon one antivenom-SAIMR Polyvalent. Although effective in treating snakebite, SAIMR Polyvalent is difficult to source outside its manufacturing country (South Africa) and is dauntingly expensive. We compared the preclinical venom-neutralising efficacy of two alternative antivenoms with that of SAIMR Polyvalent against the lethal and tissue-destructive effects of venoms from five species of medically important snakes using in vivo murine assays. The test antivenoms were 'Panafrican' manufactured by Instituto Clodomiro Picado and 'PANAF' manufactured by Premium Serums & Vaccines.

PRINCIPAL FINDINGS

In vivo murine preclinical studies identified both test antivenoms were equally or more effective than SAIMR Polyvalent at neutralising lethal and tissue-destructive effects of Naja mossambica venom. Both test antivenoms were less effective than SAIMR Polyvalent at neutralising the lethal effects of Bitis arietans, Dendroaspis polylepis, Hemachatus haemachatus and Naja annulifera venoms, but similarly effective at neutralising tissue damage induced by B. arietans and H. haemachatus venoms. In vitro immunological assays identified that the titres and toxin-specificities of immunoglobulins (iGs) in the test antivenoms were comparable to that of SAIMR Polyvalent. Plasma clotting disturbances by H. haemachatus and N. mossambica were neutralised by the test antivenoms, whereas SAIMR Polyvalent failed to neutralise this bioactivity of N. mossambica venom. B. arietans SVMP activity was equally reduced by all three antivenoms, and H. haemachatus and N. mossambica PLA2 activities were neutralised by all three antivenoms.

CONCLUSIONS

While both Panafrican and PANAF antivenoms exhibited promising preclinical efficacies, both were less poly-specifically effective than SAIMR Polyvalent in these murine assays. The efficacy of these antivenoms against the lethal and tissue-destructive effects of N. mossambica venom, the most common biting species in Eswatini, identify that Panafrican and PANAF antivenoms offer effective alternatives to SAIMR Polyvalent for the treatment of snakebite in Eswatini, and potentially for neighbouring countries.

Validation of a Culturally Relevant Snakebite Envenomation Clinical Practice Guideline in Brazil

Snakebite envenoming (SBE) is a neglected tropical disease with significant global morbidity and mortality. Even when antivenom is available in low-resource areas, health workers do not receive adequate training to manage SBEs. This study aims to develop and validate a clinical practice guideline (CPG) for SBE management across Brazil. A panel of expert judges with academic and/or technical expertise in SBE management performed content validation. The content validity index (CVI) score was 90% for CPG objectives, 89% for structure and presentation and 92% for relevance and classified the CPG as valid. A semantic validation was performed by analyzing focus group discussions with doctors and nurses from three municipalities of the Brazilian Amazon, after a 5-day meeting during which the CPG was presented. Two central themes emerged: knowledge acquired during the meeting and recommendations for improving the CPG. Based on these results, the CPG was revised into a final version. This study presents the successful development and validation process of a CPG for SBE management, which is targeted to a specific low-resource, high-burden setting. This development and validation process can be adapted to other settings and/or other neglected tropical diseases.

Situation of snakebite, antivenom market and access to antivenoms in ASEAN countries

INTRODUCTION

Snakebite envenoming is a neglected tropical disease posing public health challenges globally. The Association of Southeast Asian Nations (ASEAN) countries are among the tropical regions with disproportionately high incidence of snakebite. Hence, this study aimed to review the situation of snakebite, antivenom market and access to antivenoms in ASEAN.

METHODS

This mixed-methods study included comprehensive literature review and in-depth interviews with key informants to assess the situation of management system of snakebite, antivenom market and access to antivenoms in seven ASEAN countries, including Malaysia, Thailand, Indonesia, Philippines, Vietnam, Lao PDR and Myanmar. Data were analysed by a framework method.

RESULTS

ASEAN have developed various strategies to improve outcomes of snakebite victims. Five domestic antivenom manufacturers in the region produce up to 288 375 vials of antivenoms annually with the value of US$13 058 053 million which could treat 42 213 snakebite victims. However, there remain challenges to be addressed especially the lack of snakebite-related informatics system, inadequate antivenoms at the healthcare facilities and when the majority of snakebite victims seek traditional healers instead of conventional treatment.

CONCLUSION

Improving the situation of snakebite and antivenom is not only about the availability of antivenom, but the whole landscape of surrounding management and supporting system. The assessment of the situation of snakebite and antivenom is crucial for countries or regions where snakebites are prevalent to recognise their current standpoint to inform the development of strategies to achieve the goal set by the WHO of halving the global burden of snakebite by 2030.