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Chowdhury MAW, Müller J, Ghose A, Amin R, Sayeed AA, Kuch U, Faiz MA. Combining species distribution models and big datasets may provide finer assessments of snakebite impacts. PLoS Negl Trop Dis 2024; 18:e0012161. [PMID: 38768190 PMCID: PMC11142713 DOI: 10.1371/journal.pntd.0012161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Revised: 05/31/2024] [Accepted: 04/22/2024] [Indexed: 05/22/2024] Open
Abstract
BACKGROUND Snakebite is a major poverty-related neglected tropical disease. An integrated scientific approach is needed to understand the dynamics of this important health issue. Our objective was to estimate snakebite occurrence in a tropical area by using a blend of ecological modelling and robust statistical analysis. METHODS The present study used climatic, environmental, and human population density data to determine the area with snakebite occurrence-probability for the first time in Bangladesh. We also analysed a large, 16-year dataset of hospitalized snakebite cases to reveal the epidemiology of snakebite in the south-eastern zone of the country. FINDINGS Our results show that cobra bite is the most commonly occurring venomous snakebite in humans (around ~12% of the total yearly snakebite records), and men are more frequently bitten than women (2/3 of human victims are men). Most bites occur during the rainy season for cobra and green pit viper, while krait bites are not restricted to any particular season. As snakebite incidents are closely related to climate conditions, we can model snakebite risk using temperature and precipitation variables. Whereas there is a lack of snakebite reports from several parts of the study area in official records, our models predict that the entire study area is favourable for snakebite incidents. Based on the combined evidence we estimate that about 200,000 snakebite events occur every year in the south-eastern part of Bangladesh alone. Considering future global climate change, our model projections show that snakebite incidence in Bangladesh might not significantly decrease in the future (- 2070-); however, the distribution of probabilities might change, with a predicted increase of snakebite incidence in the hilly areas of the country. CONCLUSIONS Using climatic data to predict snakebite incidence in Bangladesh allowed us to provide estimations of the total annual number of snakebite cases in the study area. As in most countries, the scarcity of accurate epidemiological data in official records might have masked the real magnitude of this problem. Our analysis suggests that the problem of snakebite envenoming in Bangladesh might be worse than currently perceived. A long-term sustainable snakebite program plan should be designed and institutionalized, considering climatic, geographical and human demographic variables, to obtain better data and facilitate the implementation of accurate snakebite management programs for this country.
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Affiliation(s)
- Mohammad Abdul Wahed Chowdhury
- Department of Zoology, University of Chittagong, Chattogram, Bangladesh
- Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Berlin, Germany
- Institut für Biologie, Humboldt-Universität zu Berlin, Berlin, Germany
- Venom Research Centre, Department of Medicine, Chittagong Medical College, Chattogram, Bangladesh
| | - Johannes Müller
- Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Berlin, Germany
- Institut für Biologie, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Aniruddha Ghose
- Venom Research Centre, Department of Medicine, Chittagong Medical College, Chattogram, Bangladesh
- Department of Medicine, Chittagong Medical College, Chattogram, Bangladesh
| | - Robed Amin
- Venom Research Centre, Department of Medicine, Chittagong Medical College, Chattogram, Bangladesh
- Directorate General of Health Services, Ministry of Health and Family Welfare, Dhaka, Bangladesh
| | - Abdullah Abu Sayeed
- Venom Research Centre, Department of Medicine, Chittagong Medical College, Chattogram, Bangladesh
- Department of Medicine, Chittagong Medical College, Chattogram, Bangladesh
| | - Ulrich Kuch
- Venom Research Centre, Department of Medicine, Chittagong Medical College, Chattogram, Bangladesh
- Institute of Occupational Medicine, Social Medicine and Environmental Medicine, Goethe University, Frankfurt am Main, Germany
| | - Mohammad Abul Faiz
- Venom Research Centre, Department of Medicine, Chittagong Medical College, Chattogram, Bangladesh
- Dev Care Foundation, Chattogram, Bangladesh
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Marriott AE, Casewell NR, Lilley E, Gutiérrez JM, Ainsworth S. Improving in vivo assays in snake venom and antivenom research: A community discussion. F1000Res 2024; 13:192. [PMID: 38708289 PMCID: PMC11066530 DOI: 10.12688/f1000research.148223.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/06/2024] [Indexed: 05/07/2024] Open
Abstract
On the 26 th January 2023, a free to attend, 'improving in vivo snake venom research: a community discussion' meeting was held virtually. This webinar brought together researchers from around the world to discuss current neutralisation of venom lethality mouse assays that are used globally to assess the efficacy of therapies for snakebite envenoming. The assay's strengths and weaknesses were highlighted, and we discussed what improvements could be made to refine and reduce animal testing, whilst supporting preclinical antivenom and drug discovery for snakebite envenoming. This report summarises the issues highlighted, the discussions held, with additional commentary on key perspectives provided by the authors.
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Affiliation(s)
- Amy E Marriott
- Department of Infection Biology and Microbiomes, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, England, L3 5RF, UK
- Centre for Snakebite Research and Interventions, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Nicholas R Casewell
- Centre for Snakebite Research and Interventions, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Elliot Lilley
- National Centre for the Replacement, Reduction and Refinement of Animals in Research, London, NW1 2BE, UK
| | - José-María Gutiérrez
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José, 11501-2060, Costa Rica
| | - Stuart Ainsworth
- Department of Infection Biology and Microbiomes, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, England, L3 5RF, UK
- Centre for Snakebite Research and Interventions, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
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Solano G, Cunningham S, Edge RJ, Duran G, Sanchez A, Villalta M, Clare RH, Wilkinson MC, Marriott AE, Abada C, Menzies SK, Keen M, Lalloo DG, Stienstra Y, Abouyannis M, Casewell NR, León G, Ainsworth S. 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. BMJ Glob Health 2024; 9:e014813. [PMID: 38485142 PMCID: PMC10941113 DOI: 10.1136/bmjgh-2023-014813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Accepted: 02/25/2024] [Indexed: 03/17/2024] Open
Abstract
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.
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Affiliation(s)
- Gabriela Solano
- Instituto Clodomiro Picado, Universidad de Costa Rica, San Jose, Costa Rica
| | | | - Rebecca J Edge
- Liverpool School of Tropical Medicine, Liverpool, UK
- Department of Infection Biology and Microbiomes, University of Liverpool, Liverpool, UK
| | - Gina Duran
- Instituto Clodomiro Picado, Universidad de Costa Rica, San Jose, Costa Rica
| | - Adriana Sanchez
- Instituto Clodomiro Picado, Universidad de Costa Rica, San Jose, Costa Rica
| | - Mauren Villalta
- Instituto Clodomiro Picado, Universidad de Costa Rica, San Jose, Costa Rica
| | | | | | - Amy E Marriott
- Liverpool School of Tropical Medicine, Liverpool, UK
- Department of Infection Biology and Microbiomes, University of Liverpool, Liverpool, UK
| | - Camille Abada
- Liverpool School of Tropical Medicine, Liverpool, UK
| | | | - Molly Keen
- Liverpool School of Tropical Medicine, Liverpool, UK
| | - David G Lalloo
- Liverpool School of Tropical Medicine, Liverpool, UK
- Malawi Liverpool Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - Ymkje Stienstra
- Liverpool School of Tropical Medicine, Liverpool, UK
- Department of Internal Medicine/Infectious Diseases, University of Groningen, Groningen, The Netherlands
| | | | | | - Guillermo León
- Instituto Clodomiro Picado, Universidad de Costa Rica, San Jose, Costa Rica
| | - Stuart Ainsworth
- Liverpool School of Tropical Medicine, Liverpool, UK
- Department of Infection Biology and Microbiomes, University of Liverpool, Liverpool, UK
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Borri J, Gutiérrez JM, Knudsen C, Habib AG, Goldstein M, Tuttle A. Landscape of toxin-neutralizing therapeutics for snakebite envenoming (2015-2022): Setting the stage for an R&D agenda. PLoS Negl Trop Dis 2024; 18:e0012052. [PMID: 38530781 PMCID: PMC10965046 DOI: 10.1371/journal.pntd.0012052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Accepted: 03/05/2024] [Indexed: 03/28/2024] Open
Abstract
BACKGROUND Progress in snakebite envenoming (SBE) therapeutics has suffered from a critical lack of data on the research and development (R&D) landscape. A database characterising this information would be a powerful tool for coordinating and accelerating SBE R&D. To address this need, we aimed to identify and categorise all active investigational candidates in development for SBE and all available or marketed products. METHODOLOGY/PRINCIPAL FINDINGS In this landscape study, publicly available data and literature were reviewed to canvas the state of the SBE therapeutics market and research pipeline by identifying, characterising, and validating all investigational drug and biologic candidates with direct action on snake venom toxins, and all products available or marketed from 2015 to 2022. We identified 127 marketed products and 196 candidates in the pipeline, describing a very homogenous market of similar but geographically bespoke products and a diverse but immature pipeline, as most investigational candidates are at an early stage of development, with only eight candidates in clinical development. CONCLUSIONS/SIGNIFICANCE Further investment and research is needed to address the shortfalls in products already on the market and to accelerate R&D for new therapeutics. This should be accompanied by efforts to converge on shared priorities and reshape the current SBE R&D ecosystem to ensure translation of innovation and access.
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Affiliation(s)
- Juliette Borri
- Policy Cures Research, Sydney, New South Wales, Australia
| | - José María Gutiérrez
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
| | | | - Abdulrazaq G. Habib
- Infectious and Tropical Diseases Unit, Department of Medicine, Bayero University, Kano, Nigeria
| | - Maya Goldstein
- Policy Cures Research, Sydney, New South Wales, Australia
| | - Andrew Tuttle
- Policy Cures Research, Sydney, New South Wales, Australia
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de Oliveira ALN, Lacerda MT, Ramos MJ, Fernandes PA. Viper Venom Phospholipase A2 Database: The Structural and Functional Anatomy of a Primary Toxin in Envenomation. Toxins (Basel) 2024; 16:71. [PMID: 38393149 PMCID: PMC10893444 DOI: 10.3390/toxins16020071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 01/04/2024] [Accepted: 01/13/2024] [Indexed: 02/25/2024] Open
Abstract
Viper venom phospholipase A2 enzymes (vvPLA2s) and phospholipase A2-like (PLA2-like) proteins are two of the principal toxins in viper venom that are responsible for the severe myotoxic and neurotoxic effects caused by snakebite envenoming, among other pathologies. As snakebite envenoming is the deadliest neglected tropical disease, a complete understanding of these proteins' properties and their mechanisms of action is urgently needed. Therefore, we created a database comprising information on the holo-form, cofactor-bound 3D structure of 217 vvPLA2 and PLA2-like proteins in their physiologic environment, as well as 79 membrane-bound viper species from 24 genera, which we have made available to the scientific community to accelerate the development of new anti-snakebite drugs. In addition, the analysis of the sequenced, 3D structure of the database proteins reveals essential aspects of the anatomy of the proteins, their toxicity mechanisms, and the conserved binding site areas that may anchor universal interspecific inhibitors. Moreover, it pinpoints hypotheses for the molecular origin of the myotoxicity of the PLA2-like proteins. Altogether, this study provides an understanding of the diversity of these toxins and how they are conserved, and it indicates how to develop broad, interspecies, efficient small-molecule inhibitors to target the toxin's many mechanisms of action.
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Affiliation(s)
| | | | | | - Pedro A. Fernandes
- Requimte-Faculty of Sciences, University of Porto, Rua do Campo Alegre s/n, 4169-000 Porto, Portugal; (A.L.N.d.O.); (M.T.L.); (M.J.R.)
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Werner RM, Soffa AN. Considerations for the development of a field-based medical device for the administration of adjunctive therapies for snakebite envenoming. Toxicon X 2023; 20:100169. [PMID: 37661997 PMCID: PMC10474190 DOI: 10.1016/j.toxcx.2023.100169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 07/27/2023] [Accepted: 08/12/2023] [Indexed: 09/05/2023] Open
Abstract
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.
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Schurer JM, Murara E, van Oirschot J, Ooms G. Antivenom for sale? Availability and affordability of snakebite medicines across public and private health facilities in Rwanda. Toxicon 2023; 234:107292. [PMID: 37734455 DOI: 10.1016/j.toxicon.2023.107292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 09/05/2023] [Accepted: 09/13/2023] [Indexed: 09/23/2023]
Abstract
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.
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Affiliation(s)
- Janna M Schurer
- Center for One Health, University of Global Health Equity, Butaro, Rwanda; Department of Infectious Disease and Global Health, Cummings School of Veterinary Medicine at Tufts University, North Grafton, USA.
| | - Elijah Murara
- Center for One Health, University of Global Health Equity, Butaro, Rwanda
| | | | - Gaby Ooms
- Health Action International, Amsterdam, the Netherlands; Utrecht WHO Collaborating Centre for Pharmaceutical Policy and Regulation, Division of Pharmacoepidemiology and Clinical Pharmacology, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, Utrecht, the Netherlands.
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Soopairin S, Patikorn C, Taychakhoonavudh S. Antivenom preclinical efficacy testing against Asian snakes and their availability in Asia: A systematic review. PLoS One 2023; 18:e0288723. [PMID: 37467278 DOI: 10.1371/journal.pone.0288723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Accepted: 07/04/2023] [Indexed: 07/21/2023] Open
Abstract
BACKGROUND Cross-neutralizing strategy has been applied to improve access to antivenoms, a key to reducing mortality and disability of snakebite envenoming. However, preclinical studies have been conducted to identify antivenoms' cross-neutralizing ability when clinical studies may not be considered ethical. Therefore, this study aimed to identify and summarize scattered evidence regarding the preclinical efficacy of antivenoms against Asian snakes. METHODOLOGY/PRINCIPLE FINDINGS In this systematic review, we searched for articles published until May 30, 2022, in PubMed, Scopus, Web of Science, and Embase. Preclinical studies that reported the available antivenoms' neutralizing ability against Asian snake lethality were included. Quality assessment was performed using the Systematic Review Centre for Laboratory animal Experimentation's risk of bias tool and the adapted the Animal Research Reporting In Vivo Experiments guidelines. The availability of effective antivenoms against Asian snakes was analyzed by comparing data from included studies with snakebite-information and data platforms developed by the World Health Organization. Fifty-two studies were included. Most studies assessed the antivenom efficacy against snakes from Southeast Asia (58%), followed by South Asia (35%) and East Asia (19%). Twenty-two (49%) medically important snakes had antivenom(s) with confirmed neutralizing ability. Situation analyses of the availability of effective antivenoms in Asia demonstrated that locally produced antivenoms did not cover all medically important snakes in each country. Among countries without local antivenom production, preclinical studies were conducted only in Bangladesh, Sri Lanka, and Malaysia. Risk of bias assessment was limited in some domains because of unreported data. CONCLUSIONS/SIGNIFICANCE Cross-neutralizing of antivenoms against some medically important snakes in Asia was confirmed. This strategy may improve access to geographically effective antivenoms and bypass investment in novel antivenom development, especially in countries without local antivenom production. A database should be developed to aid the development of a snakebite-information system.
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Affiliation(s)
- Sutinee Soopairin
- Department of Social and Administrative Pharmacy, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok, Thailand
| | - Chanthawat Patikorn
- Department of Social and Administrative Pharmacy, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok, Thailand
| | - Suthira Taychakhoonavudh
- Department of Social and Administrative Pharmacy, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok, Thailand
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Zdenek CN, Rodrigues CFB, Bourke LA, Tanaka-Azevedo AM, Monagle P, Fry BG. Children and Snakebite: Snake Venom Effects on Adult and Paediatric Plasma. Toxins (Basel) 2023; 15:158. [PMID: 36828472 PMCID: PMC9961128 DOI: 10.3390/toxins15020158] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 01/26/2023] [Accepted: 02/07/2023] [Indexed: 02/17/2023] Open
Abstract
Snakebite is a globally neglected tropical disease, with coagulation disturbances being the primary pathology of many deadly snake venoms. Age-related differences in human plasma have been abundantly reported, yet the effect that these differences pose regarding snakebite is largely unknown. We tested for differences in coagulotoxic effects (via clotting time) of multiple snake venoms upon healthy human adult (18+) and paediatric (median 3.3 years old) plasma in vivo and compared these effects to the time it takes the plasmas to clot without the addition of venom (the spontaneous clotting time). We tested venoms from 15 medically significant snake species (from 13 genera) from around the world with various mechanisms of coagulotoxic actions, across the three broad categories of procoagulant, pseudo-procoagulant, and anticoagulant, to identify any differences between the two plasmas in their relative pathophysiological vulnerability to snakebite. One procoagulant venom (Daboia russelii, Russell's Viper) produced significantly greater potency on paediatric plasma compared with adult plasma. In contrast, the two anticoagulant venoms (Pseudechis australis, Mulga Snake; and Bitis cornuta, Many-horned Adder) were significantly more potent on adult plasma. All other procoagulant venoms and all pseudo-procoagulant venoms displayed similar potency across both plasmas. Our preliminary results may inform future studies on the effect of snake venoms upon plasmas from different age demographics and hope to reduce the burden of snakebite upon society.
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Affiliation(s)
- Christina N. Zdenek
- Venom Evolution Lab, School of Biological Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia
| | | | - Lachlan A. Bourke
- Venom Evolution Lab, School of Biological Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Anita Mitico Tanaka-Azevedo
- Laboratório de Herpetologia, Instituto Butantan, São Paulo 05508-040, SP, Brazil
- Programa de Pós-Graduação Interunidades Em Biotecnologia, USP, IPT e Instituto Butantan, São Paulo 05508-040, SP, Brazil
| | - Paul Monagle
- Department of Paediatrics, University of Melbourne, Parkville, VIC 3010, Australia
- Haematology Research, Murdoch children’s Research Institute, Flemington Rd., Parkville, VIC 3052, Australia
- Department of Clinical Haematology, Royal Children’s Hospital, Flemington Rd., Parkville, VIC 3052, Australia
- Kids Cancer Centre, Sydney Children’s Hospital, High St., Randwick, NSW 2031, Australia
| | - Bryan G. Fry
- Venom Evolution Lab, School of Biological Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia
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Lian Q, Zhong L, Fu K, Ji Y, Zhang X, Liu C, Huang C. Hepatic inhibitors expression profiling of venom-challenged Sinonatrix annularis and antidotal activities. Biomed Pharmacother 2022; 156:113900. [DOI: 10.1016/j.biopha.2022.113900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 10/07/2022] [Accepted: 10/17/2022] [Indexed: 11/02/2022] Open
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Schurer JM, Hirwa EM, Masimbi O, Nduwayezu R. Knowledge, attitudes, and practices: a quantitative assessment of hospital physicians and medical interns treating snakebite envenomation in Rwanda. Trans R Soc Trop Med Hyg 2022; 116:645-654. [DOI: 10.1093/trstmh/trab187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 12/10/2021] [Accepted: 12/16/2021] [Indexed: 11/13/2022] Open
Abstract
Abstract
Background
Snakebite envenomation (SBE) is a serious and potentially life-threatening condition that most often targets rural, subsistence-based farmers in sub-Saharan Africa. Rwanda is home to 13 venomous and medically important snake species. Those bitten are known to seek care from traditional healers and/or formal health facilities. No information is available on patient management at government health facilities.
Methods
This quantitative evaluation aimed to characterize knowledge, attitudes and practices related to snakebite management in Rwanda. Target respondents included physicians working at hospitals with the highest SBE caseload and medical interns. Respondents were asked to complete questionnaires on paper or online through Qualtrics.
Results
Overall, 105 physicians and 171 interns agreed to participate. Our findings suggest that overall knowledge scores were low for both groups (mean 49.4%, minimum–maximum 31.3–70.8%). Respondents were keen to receive SBE training but often lacked essential supplies needed to adhere to recommended guidelines for SBE management. One-third of respondents (34.8%) believed that traditional healers could manage SBE successfully and two-thirds (66.3%) felt that black stone therapy was an appropriate first aid practice.
Conclusions
These findings indicate a clear need for improved curricula related to SBE, enhanced supply chain management and practical mechanisms for supporting clinicians.
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Affiliation(s)
- Janna M Schurer
- Center for One Health, University of Global Health Equity , Kigali, Rwanda
- Department of Infectious Disease and Global Health, Cummings School of Veterinary Medicine at Tufts University , North Grafton, MA, USA
| | - Elise M Hirwa
- Center for One Health, University of Global Health Equity , Kigali, Rwanda
| | - Ornella Masimbi
- Educational Development and Quality Center, University of Global Health Equity , Kigali, Rwanda
| | - Richard Nduwayezu
- School of Medicine and Pharmacy, University of Rwanda , Kigali, Rwanda
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Lian Q, Zhang D, Fu K, Liu C, Cao L, Xiong K, Huang C. The molecular basis of venom resistance in the non-venomous snake Sinonatrix annularis. J Chromatogr B Analyt Technol Biomed Life Sci 2022; 1195:123182. [DOI: 10.1016/j.jchromb.2022.123182] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 02/12/2022] [Accepted: 02/15/2022] [Indexed: 12/22/2022]
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Alcoba G, Potet J, Vatrinet R, Singh S, Nanclares C, Kruse A, Den Boer M, Molfino L, Ritmeijer K. Snakebite envenoming in humanitarian crises and migration: A scoping review and the Médecins Sans Frontières experience. Toxicon X 2022; 13:100089. [PMID: 35005609 PMCID: PMC8718667 DOI: 10.1016/j.toxcx.2021.100089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 12/06/2021] [Accepted: 12/09/2021] [Indexed: 10/25/2022] Open
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Steegemans I, Sisay K, Nshimiyimana E, Gebrewold G, Piening T, Menberu Tessema E, Sahelie B, Alcoba G, Gebretsadik FS, Essink D, Collin S, Lucero E, Ritmeijer K. Treatment outcomes among snakebite patients in north-west Ethiopia-A retrospective analysis. PLoS Negl Trop Dis 2022; 16:e0010148. [PMID: 35139079 PMCID: PMC8863263 DOI: 10.1371/journal.pntd.0010148] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 02/22/2022] [Accepted: 01/05/2022] [Indexed: 11/18/2022] Open
Abstract
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.
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Affiliation(s)
- Inge Steegemans
- Médecins Sans Frontières, Amsterdam, The Netherlands
- VU University, Amsterdam, The Netherlands
| | | | | | | | | | | | | | | | | | | | - Simon Collin
- Federal University of Espírito Santo, Vitória, Brazil
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15
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Mender MM, Bolton F, Berry C, Young M. Antivenom: An immunotherapy for the treatment of snakebite envenoming in sub-Saharan Africa. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2021; 129:435-477. [PMID: 35305724 DOI: 10.1016/bs.apcsb.2021.11.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Snakebite envenoming (SBE) leads to significant morbidity and mortality, resulting in over 90,000 deaths and approximately 400,000 amputations annually. In sub-Saharan Africa (SSA) alone, SBE accounts for over 30,000 deaths per annum. Since 2017, SBE has been classified as a priority Neglected Tropical Disease (NTD) by the World Health Organisation (WHO). The major species responsible for mortality from SBE within SSA are from the Bitis, Dendroaspis, Echis and Naja genera. Pharmacologically active toxins such as metalloproteinases, serine proteinases, 3-finger toxins, kunitz-type toxins, and phospholipase A2s are the primary snake venom components. These toxins induce cytotoxicity, coagulopathy, hemorrhage, and neurotoxicity in envenomed victims. Antivenom is currently the only available venom-specific treatment for SBE and contains purified equine or ovine polyclonal antibodies, collected from donor animals repeatedly immunized with low doses of adjuvanted venom. The resulting plasma or serum contains a high titre of specific antibodies, which can then be collected and stored until required. The purified antibodies are either whole IgG, monovalent fragment antibody (Fab) or divalent fragment antibody F(ab')2. Despite pharmacokinetic and pharmacodynamic differences, all three are effective in the treatment of SBE. No antivenom is without adverse reactions but, the level of their impact and severity varies from benign early adverse reactions to the rarely occurring fatal anaphylactic shock. However, the major side effects are largely reversible with immediate administration of adrenaline and corticosteroids. There are 16 different antivenoms marketed within SSA, but the efficacy and safety profiles are only published for less than 50% of these products.
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Affiliation(s)
- Mender M Mender
- School of Bioscience, Cardiff University, Cardiff, United Kingdom; Department of Research and Development, MicroPharm Ltd, Newcastle Emlyn, United Kingdom.
| | - Fiona Bolton
- Department of Research and Development, MicroPharm Ltd, Newcastle Emlyn, United Kingdom
| | - Colin Berry
- School of Bioscience, Cardiff University, Cardiff, United Kingdom
| | - Mark Young
- School of Bioscience, Cardiff University, Cardiff, United Kingdom
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16
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Potet J, Beran D, Ray N, Alcoba G, Habib AG, Iliyasu G, Waldmann B, Ralph R, Faiz MA, Monteiro WM, de Almeida Gonçalves Sachett J, di Fabio JL, Cortés MDLÁ, Brown NI, Williams DJ. Access to antivenoms in the developing world: A multidisciplinary analysis. Toxicon X 2021; 12:100086. [PMID: 34786555 PMCID: PMC8578041 DOI: 10.1016/j.toxcx.2021.100086] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 10/01/2021] [Accepted: 10/04/2021] [Indexed: 11/21/2022] Open
Abstract
Access to safe, effective, quality-assured antivenom products that are tailored to endemic venomous snake species is a crucial component of recent coordinated efforts to reduce the global burden of snakebite envenoming. Multiple access barriers may affect the journey of antivenoms from manufacturers to the bedsides of patients. Our review describes the antivenom ecosystem at different levels and identifies solutions to overcome these challenges. At the global level, there is insufficient manufacturing output to meet clinical needs, notably for antivenoms intended for use in regions with a scarcity of producers. At national level, variable funding and deficient regulation of certain antivenom markets can lead to the procurement of substandard antivenom. This is particularly true when producers fail to seek registration of their products in the countries where they should be used, or where weak assessment frameworks allow registration without local clinical evaluation. Out-of-pocket expenses by snakebite victims are often the main source of financing antivenoms, which results in the underuse or under-dosing of antivenoms, and a preference for low-cost products regardless of efficacy. In resource-constrained rural areas, where the majority of victims are bitten, supply of antivenom in peripheral health facilities is often unreliable. Misconceptions about treatment of snakebite envenoming are common, further reducing demand for antivenom and exacerbating delays in reaching facilities equipped for antivenom use. Multifaceted interventions are needed to improve antivenom access in resource-limited settings. Particular attention should be paid to the comprehensive list of actions proposed within the WHO Strategy for Prevention and Control of Snakebite Envenoming.
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Affiliation(s)
- Julien Potet
- Médecins Sans Frontières Access Campaign, Geneva, Switzerland
| | - David Beran
- Division of Tropical and Humanitarian Medicine, Geneva University Hospitals, Geneva, Switzerland
- Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Nicolas Ray
- GeoHealth Group, Institute of Global Health, Faculty of Medicine, University of Geneva, Geneva, Switzerland
- Institute for Environmental Sciences, University of Geneva, Geneva, Switzerland
| | - Gabriel Alcoba
- Division of Tropical and Humanitarian Medicine, Geneva University Hospitals, Geneva, Switzerland
- Médecins Sans Frontières, Medical Department, Operational Center Geneva, Geneva, Switzerland
| | - Abdulrazaq Garba Habib
- Infectious Disease and Tropical Medicine Unit, Department of Medicine, College of Health Science, Bayero University Kano, Nigeria
| | - Garba Iliyasu
- Infectious Disease and Tropical Medicine Unit, Department of Medicine, College of Health Science, Bayero University Kano, Nigeria
| | | | - Ravikar Ralph
- Department of Internal Medicine & Poisons Information Center, Christian Medical College, Vellore, 632004, Tamil Nadu, India
| | | | - Wuelton Marcelo Monteiro
- Department of Research, Fundação de Medicina Tropical Dr. Heitor Vieira Dourado, Manaus, Brazil
- School of Health Sciences, Universidade Do Estado Do Amazonas, Manaus, Brazil
| | | | | | | | - Nicholas I. Brown
- Global Snakebite Initiative, 19 Haig Street, Ashgrove, Qld, 4060, Australia
- University of Queensland, Australia
| | - David J. Williams
- Global Snakebite Initiative, 19 Haig Street, Ashgrove, Qld, 4060, Australia
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17
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Martins D, Potet J, Ribeiro I. Snakebites and COVID-19: two crises, one research and development opportunity. BMJ Glob Health 2021; 6:e006913. [PMID: 34697086 PMCID: PMC8557241 DOI: 10.1136/bmjgh-2021-006913] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 10/13/2021] [Indexed: 12/31/2022] Open
Affiliation(s)
- Diogo Martins
- Snakebites Priority Area, Wellcome Trust, London, UK
- Faculty of Public Health and Policy, London School of Hygiene & Tropical Medicine, London, UK
| | - Julien Potet
- Neglected Tropical Diseases Advisor, Médecins Sans Frontières Access Campaign, Geneva, Switzerland
| | - Isabela Ribeiro
- Research and Development - Dynamic Portfolio Unit, Drugs for Neglected Diseases initiative, Geneva, Switzerland
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18
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Ooms GI, van Oirschot J, Okemo D, Waldmann B, Erulu E, Mantel-Teeuwisse AK, van den Ham HA, Reed T. Availability, affordability and stock-outs of commodities for the treatment of snakebite in Kenya. PLoS Negl Trop Dis 2021; 15:e0009702. [PMID: 34398889 PMCID: PMC8389522 DOI: 10.1371/journal.pntd.0009702] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 08/26/2021] [Accepted: 08/03/2021] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Annually, about 2.7 million snakebite envenomings occur globally. Alongside antivenom, patients usually require additional care to treat envenoming symptoms and antivenom side effects. Efforts are underway to improve snakebite care, but evidence from the ground to inform this is scarce. This study, therefore, investigated the availability, affordability, and stock-outs of antivenom and commodities for supportive snakebite care in health facilities across Kenya. METHODOLOGY/PRINCIPAL FINDINGS This study used an adaptation of the standardised World Health Organization (WHO)/Health Action International methodology. Data on commodity availability, prices and stock-outs were collected in July-August 2020 from public (n = 85), private (n = 36), and private not-for-profit (n = 12) facilities in Kenya. Stock-outs were measured retrospectively for a twelve-month period, enabling a comparison of a pre-COVID-19 period to stock-outs during COVID-19. Affordability was calculated using the wage of a lowest-paid government worker (LPGW) and the impoverishment approach. Accessibility was assessed combining the WHO availability target (≥80%) and LPGW affordability (<1 day's wage) measures. Overall availability of snakebite commodities was low (43.0%). Antivenom was available at 44.7% of public- and 19.4% of private facilities. Stock-outs of any snakebite commodity were common in the public- (18.6%) and private (11.7%) sectors, and had worsened during COVID-19 (10.6% versus 17.0% public sector, 8.4% versus 11.7% private sector). Affordability was not an issue in the public sector, while in the private sector the median cost of one vial of antivenom was 14.4 days' wage for an LPGW. Five commodities in the public sector and two in the private sector were deemed accessible. CONCLUSIONS Access to snakebite care is problematic in Kenya and seemed to have worsened during COVID-19. To improve access, efforts should focus on ensuring availability at both lower- and higher-level facilities, and improving the supply chain to reduce stock-outs. Including antivenom into Universal Health Coverage benefits packages would further facilitate accessibility.
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Affiliation(s)
- Gaby Isabelle Ooms
- Health Action International, Amsterdam, The Netherlands
- Utrecht Centre for Pharmaceutical Policy and Regulation, Division of Pharmacoepidemiology and Clinical Pharmacology, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, Utrecht, The Netherlands
| | | | | | | | | | - Aukje K Mantel-Teeuwisse
- Utrecht Centre for Pharmaceutical Policy and Regulation, Division of Pharmacoepidemiology and Clinical Pharmacology, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, Utrecht, The Netherlands
| | - Hendrika A van den Ham
- Utrecht Centre for Pharmaceutical Policy and Regulation, Division of Pharmacoepidemiology and Clinical Pharmacology, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, Utrecht, The Netherlands
| | - Tim Reed
- Health Action International, Amsterdam, The Netherlands
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19
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Abouyannis M, Aggarwal D, Lalloo DG, Casewell NR, Hamaluba M, Esmail H. Clinical outcomes and outcome measurement tools reported in randomised controlled trials of treatment for snakebite envenoming: A systematic review. PLoS Negl Trop Dis 2021; 15:e0009589. [PMID: 34339410 PMCID: PMC8360524 DOI: 10.1371/journal.pntd.0009589] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 08/12/2021] [Accepted: 06/24/2021] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND Snakebite is a priority neglected tropical disease and causes a range of complications that vary depending on the snake species. Randomised clinical trials have used varied outcome measures that do not allow results to be compared or combined. In accordance with the Core Outcomes Measurements in Effectiveness Trials (COMET) initiative, this systematic review aims to support the development of a globally relevant core outcome set for snakebite. METHODS All randomised controlled trials, secondary analyses of randomised controlled trials and study protocols investigating the efficacy of therapeutics for human snakebite envenoming were eligible for inclusion. Study screening and data extraction were conducted in duplicate by two independent reviewers. All primary and secondary outcome measures were extracted and compiled, as were adverse event outcome measures. Similar outcome measures were grouped into domains. The study was prospectively registered with PROSPERO: CRD42020196160. RESULTS This systematic review included 43 randomised controlled trials, two secondary analyses and 13 study protocols. A total of 382 outcome measures were extracted and, after duplicates were merged, there were 153 unique outcomes. The most frequently used outcome domain ('venom antigenaemia') was included in less than one third of the studies. The unique outcomes were classified into 60 outcome domains. Patient-centred outcomes were used in only three of the studies. DISCUSSION Significant heterogeneity in outcome measures exists in snakebite clinical trials. Consensus is needed to select outcome measures that are valid, reliable, patient-centred and feasible. The results of this systematic review strongly support the development of a core outcome set for use in snakebite clinical trials.
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Affiliation(s)
- Michael Abouyannis
- Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- KEMRI-Wellcome Research Programme, Kilifi, Kenya
| | - Dinesh Aggarwal
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - David G. Lalloo
- Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Nicholas R. Casewell
- Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Mainga Hamaluba
- KEMRI-Wellcome Research Programme, Kilifi, Kenya
- Centre for Tropical Medicine & Global Health, Nuffield Department of Medicine, Oxford, United Kingdom
| | - Hanif Esmail
- MRC clinical trials unit at UCL, London, United Kingdom
- Institute for Global Health, University College London, London, United Kingdom
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20
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Albulescu LO, Hale MS, Ainsworth S, Alsolaiss J, Crittenden E, Calvete JJ, Evans C, Wilkinson MC, Harrison RA, Kool J, Casewell NR. Preclinical validation of a repurposed metal chelator as an early-intervention therapeutic for hemotoxic snakebite. Sci Transl Med 2021; 12:12/542/eaay8314. [PMID: 32376771 DOI: 10.1126/scitranslmed.aay8314] [Citation(s) in RCA: 56] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 01/22/2020] [Accepted: 03/19/2020] [Indexed: 12/18/2022]
Abstract
Snakebite envenoming causes 138,000 deaths annually, and ~400,000 victims are left with permanent disabilities. Envenoming by saw-scaled vipers (Viperidae: Echis) leads to systemic hemorrhage and coagulopathy and represents a major cause of snakebite mortality and morbidity in Africa and Asia. The only specific treatment for snakebite, antivenom, has poor specificity and low affordability and must be administered in clinical settings because of its intravenous delivery and high rates of adverse reactions. This requirement results in major treatment delays in resource-poor regions and substantially affects patient outcomes after envenoming. Here, we investigated the value of metal ion chelators as prehospital therapeutics for snakebite. Among the tested chelators, dimercaprol (British anti-Lewisite) and its derivative 2,3-dimercapto-1-propanesulfonic acid (DMPS) were found to potently antagonize the activity of Zn2+-dependent snake venom metalloproteinases in vitro. Moreover, DMPS prolonged or conferred complete survival in murine preclinical models of envenoming against a variety of saw-scaled viper venoms. DMPS also considerably extended survival in a "challenge and treat" model, where drug administration was delayed after venom injection and the oral administration of this chelator provided partial protection against envenoming. Last, the potential clinical scenario of early oral DMPS therapy combined with a delayed, intravenous dose of conventional antivenom provided prolonged protection against the lethal effects of envenoming in vivo. Our findings demonstrate that the safe and affordable repurposed metal chelator DMPS can effectively neutralize saw-scaled viper venoms in vitro and in vivo and highlight the promise of this drug as an early, prehospital, therapeutic intervention for hemotoxic snakebite envenoming.
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Affiliation(s)
- Laura-Oana Albulescu
- Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Pembroke Place, L3 5QA Liverpool, UK
| | - Melissa S Hale
- Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Pembroke Place, L3 5QA Liverpool, UK
| | - Stuart Ainsworth
- Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Pembroke Place, L3 5QA Liverpool, UK
| | - Jaffer Alsolaiss
- Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Pembroke Place, L3 5QA Liverpool, UK
| | - Edouard Crittenden
- Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Pembroke Place, L3 5QA Liverpool, UK
| | - Juan J Calvete
- Laboratorio de Venómica Estructural y Funcional, Instituto de Biomedicina de Valencia, CSIC, Valencia 46010, Spain
| | - Chloe Evans
- Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Pembroke Place, L3 5QA Liverpool, UK
| | - Mark C Wilkinson
- Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Pembroke Place, L3 5QA Liverpool, UK
| | - Robert A Harrison
- Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Pembroke Place, L3 5QA Liverpool, UK.,Centre for Drugs and Diagnostics, Liverpool School of Tropical Medicine, Pembroke Place, L3 5QA Liverpool, UK
| | - Jeroen Kool
- Amsterdam Institute for Molecules Medicines and Systems, Division of BioAnalytical Chemistry, Department of Chemistry and Pharmaceutical Sciences, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081HV Amsterdam, Netherlands
| | - Nicholas R Casewell
- Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Pembroke Place, L3 5QA Liverpool, UK. .,Centre for Drugs and Diagnostics, Liverpool School of Tropical Medicine, Pembroke Place, L3 5QA Liverpool, UK
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21
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Clare RH, Hall SR, Patel RN, Casewell NR. Small Molecule Drug Discovery for Neglected Tropical Snakebite. Trends Pharmacol Sci 2021; 42:340-353. [DOI: 10.1016/j.tips.2021.02.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Revised: 02/24/2021] [Accepted: 02/26/2021] [Indexed: 12/31/2022]
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22
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Knudsen C, Jürgensen JA, Føns S, Haack AM, Friis RUW, Dam SH, Bush SP, White J, Laustsen AH. Snakebite Envenoming Diagnosis and Diagnostics. Front Immunol 2021; 12:661457. [PMID: 33995385 PMCID: PMC8113877 DOI: 10.3389/fimmu.2021.661457] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 03/29/2021] [Indexed: 11/13/2022] Open
Abstract
Snakebite envenoming is predominantly an occupational disease of the rural tropics, causing death or permanent disability to hundreds of thousands of victims annually. The diagnosis of snakebite envenoming is commonly based on a combination of patient history and a syndromic approach. However, the availability of auxiliary diagnostic tests at the disposal of the clinicians vary from country to country, and the level of experience within snakebite diagnosis and intervention may be quite different for clinicians from different hospitals. As such, achieving timely diagnosis, and thus treatment, is a challenge faced by treating personnel around the globe. For years, much effort has gone into developing novel diagnostics to support diagnosis of snakebite victims, especially in rural areas of the tropics. Gaining access to affordable and rapid diagnostics could potentially facilitate more favorable patient outcomes due to early and appropriate treatment. This review aims to highlight regional differences in epidemiology and clinical snakebite management on a global scale, including an overview of the past and ongoing research efforts within snakebite diagnostics. Finally, the review is rounded off with a discussion on design considerations and potential benefits of novel snakebite diagnostics.
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Affiliation(s)
- Cecilie Knudsen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
- BioPorto Diagnostics A/S, Hellerup, Denmark
| | - Jonas A. Jürgensen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Sofie Føns
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Aleksander M. Haack
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Rasmus U. W. Friis
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Søren H. Dam
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Sean P. Bush
- Department of Emergency Medicine, Yale School of Medicine, New Haven, CT, United States
| | - Julian White
- Toxinology Department, Women’s and Children’s Hospital, North Adelaide, SA, Australia
| | - Andreas H. Laustsen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
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23
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Seneci L, Zdenek CN, Chowdhury A, Rodrigues CFB, Neri-Castro E, Bénard-Valle M, Alagón A, Fry BG. A Clot Twist: Extreme Variation in Coagulotoxicity Mechanisms in Mexican Neotropical Rattlesnake Venoms. Front Immunol 2021; 12:612846. [PMID: 33815366 PMCID: PMC8011430 DOI: 10.3389/fimmu.2021.612846] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 02/11/2021] [Indexed: 12/11/2022] Open
Abstract
Rattlesnakes are a diverse clade of pit vipers (snake family Viperidae, subfamily Crotalinae) that consists of numerous medically significant species. We used validated in vitro assays measuring venom-induced clotting time and strength of any clots formed in human plasma and fibrinogen to assess the coagulotoxic activity of the four medically relevant Mexican rattlesnake species Crotalus culminatus, C. mictlantecuhtli, C. molossus, and C. tzabcan. We report the first evidence of true procoagulant activity by Neotropical rattlesnake venom in Crotalus culminatus. This species presented a strong ontogenetic coagulotoxicity dichotomy: neonates were strongly procoagulant via Factor X activation, whereas adults were pseudo-procoagulant in that they converted fibrinogen into weak, unstable fibrin clots that rapidly broke down, thereby likely contributing to net anticoagulation through fibrinogen depletion. The other species did not activate clotting factors or display an ontogenetic dichotomy, but depleted fibrinogen levels by cleaving fibrinogen either in a destructive (non-clotting) manner or via a pseudo-procoagulant mechanism. We also assessed the neutralization of these venoms by available antivenom and enzyme-inhibitors to provide knowledge for the design of evidence-based treatment strategies for envenomated patients. One of the most frequently used Mexican antivenoms (Bioclon Antivipmyn®) failed to neutralize the potent procoagulant toxic action of neonate C. culminatus venom, highlighting limitations in snakebite treatment for this species. However, the metalloprotease inhibitor Prinomastat substantially thwarted the procoagulant venom activity, while 2,3-dimercapto-1-propanesulfonic acid (DMPS) was much less effective. These results confirm that venom-induced Factor X activation (a procoagulant action) is driven by metalloproteases, while also suggesting Prinomastat as a more promising potential adjunct treatment than DMPS for this species (with the caveat that in vivo studies are necessary to confirm this potential clinical use). Conversely, the serine protease inhibitor 4-(2-aminoethyl)benzenesulfonyl fluoride hydrochloride (AEBSF) inhibited the direct fibrinogen cleaving actions of C. mictlantecuhtli venom, thereby revealing that the pseudo-procoagulant action is driven by kallikrein-type serine proteases. Thus, this differential ontogenetic variation in coagulotoxicity patterns poses intriguing questions. Our results underscore the need for further research into Mexican rattlesnake venom activity, and also highlights potential limitations of current antivenom treatments.
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Affiliation(s)
- Lorenzo Seneci
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD, Australia.,Institute of Biology Leiden (IBL), Leiden University, Leiden, Netherlands
| | - Christina N Zdenek
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD, Australia
| | - Abhinandan Chowdhury
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD, Australia.,Department of Biochemistry and Microbiology, North South University, Dhaka, Bangladesh
| | - Caroline F B Rodrigues
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD, Australia.,Laboratório de Herpetologia, Instituto Butantan, São Paulo, Brazil
| | - Edgar Neri-Castro
- Instituto de Biotecnología, Universidad Autónoma de México, Cuernavaca, Mexico
| | - Melisa Bénard-Valle
- Instituto de Biotecnología, Universidad Autónoma de México, Cuernavaca, Mexico
| | - Alejandro Alagón
- Instituto de Biotecnología, Universidad Autónoma de México, Cuernavaca, Mexico
| | - Bryan G Fry
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD, Australia
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24
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Watson JA, Lamb T, Holmes J, Warrell DA, Thwin KT, Aung ZL, Oo MZ, Nwe MT, Smithuis F, Ashley EA. A Bayesian phase 2 model based adaptive design to optimise antivenom dosing: Application to a dose-finding trial for a novel Russell's viper antivenom in Myanmar. PLoS Negl Trop Dis 2020; 14:e0008109. [PMID: 33196672 PMCID: PMC7704047 DOI: 10.1371/journal.pntd.0008109] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Revised: 11/30/2020] [Accepted: 10/10/2020] [Indexed: 01/15/2023] Open
Abstract
For most antivenoms there is little information from clinical studies to infer the relationship between dose and efficacy or dose and toxicity. Antivenom dose-finding studies usually recruit too few patients (e.g. fewer than 20) relative to clinically significant event rates (e.g. 5%). Model based adaptive dose-finding studies make efficient use of accrued patient data by using information across dosing levels, and converge rapidly to the contextually defined 'optimal dose'. Adequate sample sizes for adaptive dose-finding trials can be determined by simulation. We propose a model based, Bayesian phase 2 type, adaptive clinical trial design for the characterisation of optimal initial antivenom doses in contexts where both efficacy and toxicity are measured as binary endpoints. This design is illustrated in the context of dose-finding for Daboia siamensis (Eastern Russell's viper) envenoming in Myanmar. The design formalises the optimal initial dose of antivenom as the dose closest to that giving a pre-specified desired efficacy, but resulting in less than a pre-specified maximum toxicity. For Daboia siamensis envenoming, efficacy is defined as the restoration of blood coagulability within six hours, and toxicity is defined as anaphylaxis. Comprehensive simulation studies compared the expected behaviour of the model based design to a simpler rule based design (a modified '3+3' design). The model based design can identify an optimal dose after fewer patients relative to the rule based design. Open source code for the simulations is made available in order to determine adequate sample sizes for future adaptive snakebite trials. Antivenom dose-finding trials would benefit from using standard model based adaptive designs. Dose-finding trials where rare events (e.g. 5% occurrence) are of clinical importance necessitate larger sample sizes than current practice. We will apply the model based design to determine a safe and efficacious dose for a novel lyophilised antivenom to treat Daboia siamensis envenoming in Myanmar.
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Affiliation(s)
- James A. Watson
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Thomas Lamb
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Myanmar-Oxford Clinical Research Unit, Yangon, Myanmar
| | - Jane Holmes
- Centre for Statistics in Medicine, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - David A. Warrell
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | | | | | - Min Zaw Oo
- University of Medicine 2, Yangon, Myanmar
| | - Myat Thet Nwe
- Myanmar-Oxford Clinical Research Unit, Yangon, Myanmar
| | - Frank Smithuis
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Myanmar-Oxford Clinical Research Unit, Yangon, Myanmar
| | - Elizabeth A. Ashley
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Myanmar-Oxford Clinical Research Unit, Yangon, Myanmar
- Lao-Oxford-Mahosot Hospital Wellcome Trust Research Unit, Vientiane, Laos
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Harrison RA, Williams DJ. Outlining progress since the first International Snakebite Awareness Day and some key challenges for next year. Trans R Soc Trop Med Hyg 2020; 113:577-578. [PMID: 31539057 DOI: 10.1093/trstmh/trz096] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 08/08/2019] [Indexed: 11/13/2022] Open
Affiliation(s)
- Robert A Harrison
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, UK
| | - David J Williams
- Australia Venom Research Unit, University of Melbourne, Australia
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Habib AG, Musa BM, Iliyasu G, Hamza M, Kuznik A, Chippaux JP. Challenges and prospects of snake antivenom supply in sub-Saharan Africa. PLoS Negl Trop Dis 2020; 14:e0008374. [PMID: 32817674 PMCID: PMC7440614 DOI: 10.1371/journal.pntd.0008374] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Affiliation(s)
- Abdulrazaq G. Habib
- Health Economics & Outcomes Research (H-CORE) Group, Department of Medicine, Bayero University, Kano, Nigeria
- Venom and Antivenom Research Project (VASP), Bayero University, Kano, Nigeria
- African Snakebite Research Group (ASRG) Project, Bayero University, Kano, Nigeria
- Africa Center of Excellence in Population Health and Policy, Bayero University, Kano, Nigeria
- * E-mail:
| | - Baba M. Musa
- Health Economics & Outcomes Research (H-CORE) Group, Department of Medicine, Bayero University, Kano, Nigeria
- Africa Center of Excellence in Population Health and Policy, Bayero University, Kano, Nigeria
| | - Garba Iliyasu
- Health Economics & Outcomes Research (H-CORE) Group, Department of Medicine, Bayero University, Kano, Nigeria
- Venom and Antivenom Research Project (VASP), Bayero University, Kano, Nigeria
- African Snakebite Research Group (ASRG) Project, Bayero University, Kano, Nigeria
- Africa Center of Excellence in Population Health and Policy, Bayero University, Kano, Nigeria
| | - Muhammad Hamza
- Venom and Antivenom Research Project (VASP), Bayero University, Kano, Nigeria
- African Snakebite Research Group (ASRG) Project, Bayero University, Kano, Nigeria
| | - Andreas Kuznik
- Regeneron Pharmaceuticals, Tarrytown, New York, United States of America
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Ainsworth S, Menzies SK, Casewell NR, Harrison RA. An analysis of preclinical efficacy testing of antivenoms for sub-Saharan Africa: Inadequate independent scrutiny and poor-quality reporting are barriers to improving snakebite treatment and management. PLoS Negl Trop Dis 2020; 14:e0008579. [PMID: 32817682 PMCID: PMC7462309 DOI: 10.1371/journal.pntd.0008579] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 09/01/2020] [Accepted: 07/08/2020] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The World Health Organization's strategy to halve snakebite mortality and morbidity by 2030 includes an emphasis on a risk-benefit process assessing the preclinical efficacy of antivenoms manufactured for sub-Saharan Africa. To assist this process, we systematically collected, standardised and analysed all publicly available data on the preclinical efficacy of antivenoms designed for sub-Saharan Africa. METHODOLOGY/PRINCIPAL FINDINGS Using a systematic search of publication databases, we focused on publicly available preclinical reports of the efficacy of 16 antivenom products available in sub Saharan Africa. Publications since 1999 reporting the industry standard intravenous pre-incubation method of murine in vivo neutralisation of venom lethality (median effective dose [ED50]) were included. Eighteen publications met the criteria. To permit comparison of the several different reported ED50 values, it was necessary to standardise these to microlitre of antivenom resulting in 50% survival of mice challenged per milligram of venom (μl/mg). We were unable to identify publicly available preclinical data on four antivenoms, whilst data for six polyspecific antivenoms were restricted to a small number of venoms. Only four antivenoms were tested against a wide range of venoms. Examination of these studies for the reporting of key metrics required for interpreting antivenom ED50s were highly variable, as evidenced by eight different units being used for the described ED50 values. CONCLUSIONS/SIGNIFICANCE There is a disturbing lack of (i) preclinical efficacy testing of antivenom for sub Saharan Africa, (ii) publicly available reports and (iii) independent scrutiny of this medically important data. Where reports do exist, the methods and metrics used are highly variable. This prevents comprehensive meta-analysis of antivenom preclinical efficacy, and severely reduces the utility of antivenom ED50 results in the decision making of physicians treating patients and of national and international health agencies. Here, we propose the use of a standardised result reporting checklist to resolve this issue. Implementation of these straightforward steps will deliver uniform evaluation of products across laboratories, facilitate meta-analyses, and contribute vital information for designing the clinical trials needed to achieve the WHO target of halving snakebite morbidity and mortality by 2030.
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Affiliation(s)
- Stuart Ainsworth
- Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
| | - Stefanie K. Menzies
- Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
| | - Nicholas R. Casewell
- Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
| | - Robert A. Harrison
- Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
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Casewell NR, Jackson TNW, Laustsen AH, Sunagar K. Causes and Consequences of Snake Venom Variation. Trends Pharmacol Sci 2020; 41:570-581. [PMID: 32564899 PMCID: PMC7116101 DOI: 10.1016/j.tips.2020.05.006] [Citation(s) in RCA: 168] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 05/25/2020] [Accepted: 05/31/2020] [Indexed: 11/30/2022]
Abstract
Snake venoms are mixtures of toxins that vary extensively between and within snake species. This variability has serious consequences for the management of the world’s 1.8 million annual snakebite victims. Advances in ‘omic’ technologies have empowered toxinologists to comprehensively characterize snake venom compositions, unravel the molecular mechanisms that underpin venom variation, and elucidate the ensuing functional consequences. In this review, we describe how such mechanistic processes have resulted in suites of toxin isoforms that cause diverse pathologies in human snakebite victims and we detail how variation in venom composition can result in treatment failure. Finally, we outline current therapeutic approaches designed to circumvent venom variation and deliver next-generation treatments for the world’s most lethal neglected tropical disease.
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Affiliation(s)
- Nicholas R Casewell
- Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK.
| | - Timothy N W Jackson
- Australian Venom Research Unit, Department of Pharmacology and Therapeutics, University of Melbourne, Victoria, Australia
| | - Andreas H Laustsen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark
| | - Kartik Sunagar
- Evolutionary Venomics Laboratory, Centre for Ecological Sciences, Indian Institute of Science, Bangalore 560012, Karnataka, India
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29
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Fatal Rattlesnake Envenomation in Northernmost Brazilian Amazon: A Case Report and Literature Overview. REPORTS 2020. [DOI: 10.3390/reports3020009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Snakebite envenomations are classified as Category A Neglected Tropical Diseases by the World Health Organization. In Brazil, 405 snake species are distributed among 11 families, with the genera Bothrops and Crotalus being the most studied and main responsible for severe and lethal envenomations. In the country, Crotalus genus (i.e., rattlesnakes) is represented by Crotalus durissus species, showing seven different subspecies distributed along the country, including Crotalus durissus ruruima, which inhabits Roraima, the Brazilian nothermost state from Amazon forest. Here, we report a fatal case of a severe envenomation following a rattlesnake bite. The patient presented classic crotalic neurological signs and symptoms such as ptosis, drooling of saliva, sluggishness, macroscopic hematuria, and oliguria, which evolved to acute kidney failure (AKF) and hemodynamic instability. Although the patient was treated with the specific antivenom therapy, the severe envenomation resulted in three cardiac arrests and death of the victim in less than 38 h. This study discusses the causes of the patient death, the features of rattlesnake venom-induced AKF, and shows evidences that the Brazilian crotalic antivenom should be improved to treat rattlesnake envenomations caused by C. d. ruruima venom in Roraima state.
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Potet J, Smith J, McIver L. Reviewing evidence of the clinical effectiveness of commercially available antivenoms in sub-Saharan Africa identifies the need for a multi-centre, multi-antivenom clinical trial. PLoS Negl Trop Dis 2019; 13:e0007551. [PMID: 31233536 PMCID: PMC6615628 DOI: 10.1371/journal.pntd.0007551] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 07/09/2019] [Accepted: 06/13/2019] [Indexed: 01/28/2023] Open
Abstract
Background Snakebite envenoming kills more than more than 20,000 people in Sub-Saharan Africa every year. Poorly regulated markets have been inundated with low-price, low-quality antivenoms. This review aimed to systematically collect and analyse the clinical data on all antivenom products now available in markets of sub-Saharan Africa. Methodology/Principal findings Our market analysis identified 12 polyspecific and 4 monospecific antivenom products in African markets. Our search strategy was first based on a systematic search of publication databases, followed by manual searches and discussions with experts. All types of data, including programmatic data, were eligible. All types of publications were eligible, including grey literature. Cohorts of less than 10 patients were excluded. 26 publications met the inclusion criteria. Many publications had to be excluded because clinical outcomes were not clearly linked to a specific product. Our narrative summaries present product-specific clinical data in terms of safety and effectiveness against the different species and envenoming syndromes. Three products (EchiTabPlus, EchiTabG, SAIMR-Echis-monovalent) were found to have been tested in robust clinical studies and found effective against envenoming caused by the West African carpet viper (Echis ocellatus). Four products (Inoserp-Panafricain, Fav-Afrique, SAIMR-Polyvalent, Antivipmyn-Africa) were found to have been evaluated only in observational single-arm studies, with varying results. For nine other products, there are either no data in the public domain, or only negative data suggesting a lack of effectiveness. Conclusions/Significance Clinical data vary among the different antivenom products currently in African markets. Some products are available commercially although they have been found to lack effectiveness. The World Health Organization should strengthen its capacity to assess antivenom products, support antivenom manufacturers, and assist African countries and international aid organizations in selecting appropriate quality antivenoms. Snakebite envenomation represents one of the most neglected tropical medical conditions worldwide. Despite high levels of morbidity and mortality associated with snakebite, its neglected nature has compromised the availability and evaluation of antivenom treatment. This review was initiated by Médecins Sans Frontières’ / Doctors Without Borders (MSF) Access Campaign, as the existing antivenom access crisis in sub-Saharan Africa was deepening. This study sought to review the clinical data pertaining to each antivenom product currently available for use in sub-Saharan Africa. 16 different antivenoms were identified. A total of 26 studies met the inclusion criteria. Given the heterogeneity of study methodology and quality, data for individual antivenoms are presented in the form of a narrative analysis. Only two studies reported clinical data collected from randomized controlled trials. Consistent monitoring of the side effects of antivenom treatment was lacking. The absence of good quality data for the majority of antivenoms in sub-Saharan Africa is a major concern. Further robust data collection is required, while urgent investments are needed at the global level to ensure a sustained production of safe and effective antivenom treatment, and its affordable access across sub-Saharan Africa.
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Affiliation(s)
- Julien Potet
- Médecins Sans Frontières Access Campaign, Geneva, Switzerland
- * E-mail:
| | - James Smith
- Médecins Sans Frontières Access Campaign, Geneva, Switzerland
| | - Lachlan McIver
- Médecins Sans Frontières Access Campaign, Geneva, Switzerland
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31
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Sánchez EE, Migl C, Suntravat M, Rodriguez-Acosta A, Galan JA, Salazar E. The neutralization efficacy of expired polyvalent antivenoms: An alternative option. Toxicon 2019; 168:32-39. [PMID: 31229628 DOI: 10.1016/j.toxicon.2019.06.216] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 06/13/2019] [Accepted: 06/16/2019] [Indexed: 01/17/2023]
Abstract
The expense of production and distribution of snakebite antivenom, as well as its relatively infrequent use, has caused antivenom to be increasingly difficult to obtain and ultimately producing an alarming global shortage. Unused, expired antivenom may represent a significant, untapped resource to ameliorate this crisis. This study examines the efficacy of expired antivenom over time using in vitro, whole blood clotting, and platelet function statistics. Representatives from three years for four different global brands of polyvalent antivenom were chosen and tested against their corresponding venoms as well as other venoms that could display cross-reactivity. These antivenoms include Wyeth Polyvalent (U.S.; exp. 1997, 2001, 2003), Antivipmyn® (Mexico; exp. 2005, 2013, 2017), Biotecfars Polyvalent (Venezuela; exp. 2010, 2014, 2016), and SAIMR (South Africa; exp. 1997, 2005, 2017). Venoms of species tested were Crotalus atrox against Wyeth; C. atrox and Crotalus vegrandis against Antivipmyn®; C. atrox, C. vegrandis and Bothrops colombiensis against Biotecfar; and Bitis gabonica and Echis carinatus against South African Institute for Medical Research (SAIMR). Parameters recorded were activated clotting time (ACT), clotting rate (CR), and platelet function (PF). Preliminary results are encouraging as the antivenoms maintained significant efficacy even 20 y after their expiration date. We anticipate these results will motivate further studies and provide hope in the cases of snakebite emergencies when preferable treatments are unavailable.
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Affiliation(s)
- Elda E Sánchez
- National Natural Toxins Research Center, Texas A&M University-Kingsville, Kingsville, TX 78363-8202, USA; Department of Chemistry, Texas A&M University-Kingsville, MSC 161, Kingsville, TX 78363-8202, USA.
| | - Chesney Migl
- National Natural Toxins Research Center, Texas A&M University-Kingsville, Kingsville, TX 78363-8202, USA
| | - Montamas Suntravat
- National Natural Toxins Research Center, Texas A&M University-Kingsville, Kingsville, TX 78363-8202, USA; Department of Chemistry, Texas A&M University-Kingsville, MSC 161, Kingsville, TX 78363-8202, USA
| | - Alexis Rodriguez-Acosta
- Laboratorio de Inmunoquímica y Ultraestructura, Instituto Anatómico "José Izquierdo", Universidad Central de Venezuela, Caracas, Venezuela
| | - Jacob A Galan
- National Natural Toxins Research Center, Texas A&M University-Kingsville, Kingsville, TX 78363-8202, USA; Department of Chemistry, Texas A&M University-Kingsville, MSC 161, Kingsville, TX 78363-8202, USA
| | - Emelyn Salazar
- National Natural Toxins Research Center, Texas A&M University-Kingsville, Kingsville, TX 78363-8202, USA
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Leiva CL, Cangelosi A, Mariconda V, Farace M, Geoghegan P, Brero L, Fernández-Miyakawa M, Chacana P. IgY-based antivenom against Bothrops alternatus: Production and neutralization efficacy. Toxicon 2019; 163:84-92. [DOI: 10.1016/j.toxicon.2019.03.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 03/11/2019] [Accepted: 03/20/2019] [Indexed: 10/27/2022]
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Strategy for a globally coordinated response to a priority neglected tropical disease: Snakebite envenoming. PLoS Negl Trop Dis 2019; 13:e0007059. [PMID: 30789906 PMCID: PMC6383867 DOI: 10.1371/journal.pntd.0007059] [Citation(s) in RCA: 209] [Impact Index Per Article: 41.8] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Yakubu AS, Abdul-Mumin A, Adam A. Clinical and demographic profile of patients with snakebite in a tertiary hospital in Ghana. SAHEL MEDICAL JOURNAL 2019. [DOI: 10.4103/smj.smj_68_18] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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35
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The history of antivenoms development: Beyond Calmette and Vital Brazil. Toxicon 2018; 150:86-95. [DOI: 10.1016/j.toxicon.2018.05.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 05/08/2018] [Accepted: 05/14/2018] [Indexed: 02/04/2023]
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The snakebite problem and antivenom crisis from a health-economic perspective. Toxicon 2018; 150:115-123. [PMID: 29782952 DOI: 10.1016/j.toxicon.2018.05.009] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2018] [Revised: 05/08/2018] [Accepted: 05/14/2018] [Indexed: 11/22/2022]
Abstract
The scourge of snakebite has been well documented but largely ignored by the global health community for several decades, especially the role that economics has played in causing and exacerbating this crisis. Every year millions of people in low and middle-income countries face death, disability and disadvantage from snakebite envenoming (SBE) without access to appropriate treatment. Health-economic factors pervade every aspect of this neglected problem. A multitude of financial and commercial factors helped to cause, and now perpetuate, shortages of high quality, affordable and region-appropriate antivenom in areas where they are most needed. Alongside the death, physical disability and psychological anguish from SBE is a debilitating financial toll, which includes both direct costs of treatment and indirect costs from lost income. SBE is a problem that disproportionately affects poor, rural and agrarian communities, with most victims being young and industrious subsistence workers. The burden of envenoming is often felt by families and communities that can least afford it, and negatively impacts local and national productivity. The lack of long-term investment in health systems to properly manage SBE has led to insufficient funding for antivenom development, procurement, quality control and distribution, despite highly favourable cost effectiveness of some antivenoms. This has contributed to market failures that have seen antivenom output fall and become inaccessible to most victims. Solutions to these problems exist and are achievable, however the challenge for advocates is to appreciate the importance of health-economics and ensure that strategies to redress the economic causes and consequences of SBE are themselves cost-effective and financially sustainable.
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Calvete JJ, Rodríguez Y, Quesada-Bernat S, Pla D. Toxin-resolved antivenomics-guided assessment of the immunorecognition landscape of antivenoms. Toxicon 2018; 148:107-122. [PMID: 29704534 DOI: 10.1016/j.toxicon.2018.04.015] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 03/26/2018] [Accepted: 04/22/2018] [Indexed: 01/23/2023]
Abstract
Snakebite envenoming represents a major issue in rural areas of tropical and subtropical regions across sub-Saharan Africa, South to Southeast Asia, Latin America and Oceania. Antivenoms constitute the only scientifically validated therapy for snakebite envenomings, provided they are safe, effective, affordable, accessible and administered appropriately. However, the lack of financial incentives in a technology that has remained relatively unchanged for more than a century, has contributed to some manufacturers leaving the market and others downscaling production or increasing the prices, leading to a decline in the availability and accessibility for these life-saving antidotes to millions of rural poor most at risk from snakebites in low income countries. The shortage of antivenoms can be significantly alleviated by optimizing the use of current antivenoms (through the assessment of their specific and paraspecific efficacy against the different medically relevant homologous and heterologous snake venoms) and by generating novel polyspecific antivenoms exhibiting broad clinical spectrum and wide geographic distribution range. Research on venoms has been continuously enhanced by advances in technology. Particularly, the last decade has witnessed the development of omics strategies for unravelling the toxin composition of venoms ("venomics") and to assess the immunorecognition profile of antivenoms ("antivenomics"). Here, we review recent developments and reflect on near future innovations that promise to revolutionize the mutually enlightening relationship between evolutionary and translational venomics.
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Affiliation(s)
- Juan J Calvete
- Evolutionary and Translational Venomics Laboratory, Consejo Superior de Investigaciones Científicas (CSIC), Valencia, Spain.
| | - Yania Rodríguez
- Evolutionary and Translational Venomics Laboratory, Consejo Superior de Investigaciones Científicas (CSIC), Valencia, Spain
| | - Sarai Quesada-Bernat
- Evolutionary and Translational Venomics Laboratory, Consejo Superior de Investigaciones Científicas (CSIC), Valencia, Spain
| | - Davinia Pla
- Evolutionary and Translational Venomics Laboratory, Consejo Superior de Investigaciones Científicas (CSIC), Valencia, Spain.
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Knudsen C, Laustsen AH. Recent Advances in Next Generation Snakebite Antivenoms. Trop Med Infect Dis 2018; 3:tropicalmed3020042. [PMID: 30274438 PMCID: PMC6073149 DOI: 10.3390/tropicalmed3020042] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 04/05/2018] [Accepted: 04/09/2018] [Indexed: 12/26/2022] Open
Abstract
With the inclusion of snakebite envenoming on the World Health Organization’s list of Neglected Tropical Diseases, an incentive has been established to promote research and development effort in novel snakebite antivenom therapies. Various technological approaches are being pursued by different research groups, including the use of small molecule inhibitors against enzymatic toxins as well as peptide- and oligonucleotide-based aptamers and antibody-based biotherapeutics against both enzymatic and non-enzymatic toxins. In this article, the most recent advances in these fields are presented, and the advantages, disadvantages, and feasibility of using different toxin-neutralizing molecules are reviewed. Particular focus within small molecules is directed towards the inhibitors varespladib, batimastat, and marimastat, while in the field of antibody-based therapies, novel recombinant polyclonal plantivenom technology is discussed.
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Affiliation(s)
- Cecilie Knudsen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, DK-2800, Denmark.
| | - Andreas H Laustsen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, DK-2800, Denmark.
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Harrison RA, Oluoch GO, Ainsworth S, Alsolaiss J, Bolton F, Arias AS, Gutiérrez JM, Rowley P, Kalya S, Ozwara H, Casewell NR. Preclinical antivenom-efficacy testing reveals potentially disturbing deficiencies of snakebite treatment capability in East Africa. PLoS Negl Trop Dis 2017; 11:e0005969. [PMID: 29045429 PMCID: PMC5646754 DOI: 10.1371/journal.pntd.0005969] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 09/17/2017] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Antivenom is the treatment of choice for snakebite, which annually kills an estimated 32,000 people in sub-Saharan Africa and leaves approximately 100,000 survivors with permanent physical disabilities that exert a considerable socioeconomic burden. Over the past two decades, the high costs of the most polyspecifically-effective antivenoms have sequentially reduced demand, commercial manufacturing incentives and production volumes that have combined to create a continent-wide vacuum of effective snakebite therapy. This was quickly filled with new, less expensive antivenoms, many of which are of untested efficacy. Some of these successfully marketed antivenoms for Africa are inappropriately manufactured with venoms from non-African snakes and are dangerously ineffective. The uncertain efficacy of available antivenoms exacerbates the complexity of designing intervention measures to reduce the burden of snakebite in sub-Saharan Africa. The objective of this study was to preclinically determine the ability of antivenoms available in Kenya to neutralise the lethal effects of venoms from the most medically important snakes in East Africa. METHODS We collected venom samples from the most medically important snakes in East Africa and determined their toxicity in a mouse model. Using a 'gold standard' comparison protocol, we preclinically tested the comparative venom-neutralising efficacy of four antivenoms available in Kenya with two antivenoms of clinically-proven efficacy. To explain the variant efficacies of these antivenoms we tested the IgG-venom binding characteristics of each antivenom using in vitro IgG titre, avidity and venom-protein specificity assays. We also measured the IgG concentration of each antivenom. FINDINGS None of the six antivenoms are preclinically effective, at the doses tested, against all of the most medically important snakes of the region. The very limited snake polyspecific efficacy of two locally available antivenoms is of concern. In vitro assays of the abilities of 'test' antivenom IgGs to bind venom proteins were not substantially different from that of the 'gold standard' antivenoms. The least effective antivenoms had the lowest IgG content/vial. CONCLUSIONS Manufacture-stated preclinical efficacy statements guide decision making by physicians and antivenom purchasers in sub-Saharan Africa. This is because of the lack of both clinical data on the efficacy of most of the many antivenoms used to treat patients and independent preclinical assessment. Our preclinical efficacy assessment of antivenoms available in Kenya identifies important limitations for two of the most commonly-used antivenoms, and that no antivenom is preclinically effective against all the regionally important snakes. The potential implication to snakebite treatment is of serious concern in Kenya and elsewhere in sub-Saharan Africa, and underscores the dilemma physicians face, the need for clinical data on antivenom efficacy and the medical and societal value of establishing independent preclinical antivenom-efficacy testing facilities throughout the continent.
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Affiliation(s)
- Robert A. Harrison
- The Alistair Reid Venom Research Unit, Parasitology Department, Liverpool School of Tropical Medicine, Liverpool, Merseyside, United Kingdom
| | - George O. Oluoch
- The Institute of Primate Research, National Museums of Kenya, Karen, Nairobi, Kenya
| | - Stuart Ainsworth
- The Alistair Reid Venom Research Unit, Parasitology Department, Liverpool School of Tropical Medicine, Liverpool, Merseyside, United Kingdom
| | - Jaffer Alsolaiss
- The Alistair Reid Venom Research Unit, Parasitology Department, Liverpool School of Tropical Medicine, Liverpool, Merseyside, United Kingdom
| | - Fiona Bolton
- The Alistair Reid Venom Research Unit, Parasitology Department, Liverpool School of Tropical Medicine, Liverpool, Merseyside, United Kingdom
| | - Ana-Silvia Arias
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
| | - José-María Gutiérrez
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
| | - Paul Rowley
- The Alistair Reid Venom Research Unit, Parasitology Department, Liverpool School of Tropical Medicine, Liverpool, Merseyside, United Kingdom
| | - Stephen Kalya
- County Health Services, County Government of Baringo, Kabarnet, Baringo, Kenya
| | - Hastings Ozwara
- The Institute of Primate Research, National Museums of Kenya, Karen, Nairobi, Kenya
| | - Nicholas R. Casewell
- The Alistair Reid Venom Research Unit, Parasitology Department, Liverpool School of Tropical Medicine, Liverpool, Merseyside, United Kingdom
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Rogalski A, Soerensen C, Op den Brouw B, Lister C, Dashevsky D, Arbuckle K, Gloria A, Zdenek CN, Casewell NR, Gutiérrez JM, Wüster W, Ali SA, Masci P, Rowley P, Frank N, Fry BG. Differential procoagulant effects of saw-scaled viper (Serpentes: Viperidae: Echis) snake venoms on human plasma and the narrow taxonomic ranges of antivenom efficacies. Toxicol Lett 2017; 280:159-170. [PMID: 28847519 DOI: 10.1016/j.toxlet.2017.08.020] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 08/21/2017] [Accepted: 08/21/2017] [Indexed: 10/19/2022]
Abstract
Saw-scaled vipers (genus Echis) are one of the leading causes of snakebite morbidity and mortality in parts of Sub-Saharan Africa, the Middle East, and vast regions of Asia, constituting a public health burden exceeding that of almost any other snake genus globally. Venom-induced consumption coagulopathy, owing to the action of potent procoagulant toxins, is one of the most relevant clinical manifestations of envenomings by Echis spp. Clinical experience and prior studies examining a limited range of venoms and restricted antivenoms have demonstrated for some antivenoms an extreme lack of antivenom cross-reactivity between different species of this genus, sometimes resulting in catastrophic treatment failure. This study undertook the most comprehensive testing of Echis venom effects upon the coagulation of human plasma, and also the broadest examination of antivenom potency and cross-reactivity, to-date. 10 Echis species/populations and four antivenoms (two African, two Asian) were studied. The results indicate that the venoms are, in general, potently procoagulant but that the relative dependence on calcium or phospholipid cofactors is highly variable. Additionally, three out of the four antivenoms tested demonstrated only a very narrow taxonomic range of effectiveness in preventing coagulopathy, with only the SAIMR antivenom displaying significant levels of cross-reactivity. These results were in conflict with previous studies using prolonged preincubation of antivenom with venom to suggest effective cross-reactivity levels for the ICP Echi-Tab antivenom. These findings both inform upon potential clinical effects of envenomation in humans and highlight the extreme limitations of available treatment. It is hoped that this will spur efforts into the development of antivenoms with more comprehensive coverage for bites not only from wild snakes but also from specimens widely kept in zoological collections.
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Affiliation(s)
- Aymeric Rogalski
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia QLD 4072 Australia
| | - Christoffer Soerensen
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia QLD 4072 Australia
| | - Bianca Op den Brouw
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia QLD 4072 Australia
| | - Callum Lister
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia QLD 4072 Australia
| | - Daniel Dashevsky
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia QLD 4072 Australia
| | - Kevin Arbuckle
- Department of Biosciences, College of Science, Swansea University, Swansea SA2 8PP, UK
| | - Alexandra Gloria
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia QLD 4072 Australia
| | - Christina N Zdenek
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia QLD 4072 Australia
| | - Nicholas R Casewell
- Alistair Reid Venom Research Unit, Parasitology Department, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - José María Gutiérrez
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
| | - Wolfgang Wüster
- Molecular Ecology and Fisheries Genetics Laboratory (MEFGL), School of Biological Sciences, Bangor University, Bangor LL57 2UW, UK
| | - Syed A Ali
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia QLD 4072 Australia; HEJ Research Institute of Chemistry, International Centre for Chemical and Biological Sciences (ICCBS), University of Karachi, Karachi 75270, Pakistan
| | - Paul Masci
- Princess Alexandra Hospital, Translational Research Institute, University of Queensland, St Lucia, QLD 4072, Australia
| | - Paul Rowley
- Alistair Reid Venom Research Unit, Parasitology Department, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | | | - Bryan G Fry
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia QLD 4072 Australia.
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Rifaie F, Maharani T, Hamidy A. Where did Venomous Snakes Strike? A Spatial Statistical Analysis of Snakebite Cases in Bondowoso Regency, Indonesia. HAYATI JOURNAL OF BIOSCIENCES 2017. [DOI: 10.1016/j.hjb.2017.09.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Slagboom J, Kool J, Harrison RA, Casewell NR. Haemotoxic snake venoms: their functional activity, impact on snakebite victims and pharmaceutical promise. Br J Haematol 2017; 177:947-959. [PMID: 28233897 PMCID: PMC5484289 DOI: 10.1111/bjh.14591] [Citation(s) in RCA: 140] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2016] [Accepted: 01/09/2017] [Indexed: 12/22/2022]
Abstract
Snake venoms are mixtures of numerous proteinacious components that exert diverse functional activities on a variety of physiological targets. Because the toxic constituents found in venom vary from species to species, snakebite victims can present with a variety of life-threatening pathologies related to the neurotoxic, cytotoxic and haemotoxic effects of venom. Of the 1·8 million people envenomed by snakes every year, up to 125 000 die, while hundreds of thousands survive only to suffer with life-changing long-term morbidity. Consequently, snakebite is one of the world's most severe neglected tropical diseases. Many snake venoms exhibit strong haemotoxic properties by interfering with blood pressure, clotting factors and platelets, and by directly causing haemorrhage. In this review we provide an overview of the functional activities of haemotoxic venom proteins, the pathologies they cause in snakebite victims and how their exquisite selectivity and potency make them amenable for use as therapeutic and diagnostic tools relevant for human medicine.
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Affiliation(s)
- Julien Slagboom
- Alistair Reid Venom Research Unit, Parasitology Department, Liverpool School of Tropical Medicine, Liverpool, UK
- Division of BioAnalytical Chemistry, Department of Chemistry and Pharmaceutical Sciences, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Jeroen Kool
- Division of BioAnalytical Chemistry, Department of Chemistry and Pharmaceutical Sciences, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Robert A Harrison
- Alistair Reid Venom Research Unit, Parasitology Department, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Nicholas R Casewell
- Alistair Reid Venom Research Unit, Parasitology Department, Liverpool School of Tropical Medicine, Liverpool, UK
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Pla D, Rodríguez Y, Calvete JJ. Third Generation Antivenomics: Pushing the Limits of the In Vitro Preclinical Assessment of Antivenoms. Toxins (Basel) 2017; 9:toxins9050158. [PMID: 28489039 PMCID: PMC5450706 DOI: 10.3390/toxins9050158] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 05/05/2017] [Accepted: 05/05/2017] [Indexed: 12/18/2022] Open
Abstract
Second generation antivenomics is a translational venomics approach designed to complement in vivo preclinical neutralization assays. It provides qualitative and quantitative information on the set of homologous and heterologous venom proteins presenting antivenom-recognized epitopes and those exhibiting impaired immunoreactivity. In a situation of worrying antivenom shortage in many tropical and sub-tropical regions with high snakebite mortality and morbidity rates, such knowledge has the potential to facilitate the optimal deployment of currently existing antivenoms and to aid in the rational design of novel broad specificity antidotes. The aim of the present work was to expand the analytical capability of the immunoaffinity second-generation antivenomics platform, endowing it with the ability to determine the maximal binding capacity of an antivenom toward the different toxins present in a venom, and to quantify the fraction of venom-specific antibodies present in a given antivenom. The application of this new platform, termed third generation (3G) antivenomics, in the preclinical evaluation of antivenoms is illustrated in this paper for the case of antivenom EchiTAb-Plus-ICP® reactivity towards the toxins of homologous (B. arietans) and heterologous (N. melanoleuca) venoms.
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Affiliation(s)
- Davinia Pla
- Laboratorio de Venómica Estructural y Funcional, Instituto de Biomedicina de Valencia, CSIC, Jaime Roig 11, 46010 Valencia, Spain.
| | - Yania Rodríguez
- Laboratorio de Venómica Estructural y Funcional, Instituto de Biomedicina de Valencia, CSIC, Jaime Roig 11, 46010 Valencia, Spain.
| | - Juan J Calvete
- Laboratorio de Venómica Estructural y Funcional, Instituto de Biomedicina de Valencia, CSIC, Jaime Roig 11, 46010 Valencia, Spain.
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Caro D, Ocampo Y, Castro J, Barrios L, Salas R, Franco LA. Protective effect of Dracontium dubium against Bothrops asper venom. Biomed Pharmacother 2017; 89:1105-1114. [DOI: 10.1016/j.biopha.2017.02.080] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Revised: 02/18/2017] [Accepted: 02/21/2017] [Indexed: 01/26/2023] Open
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Alirol E, Sharma SK, Ghimire A, Poncet A, Combescure C, Thapa C, Paudel VP, Adhikary K, Taylor WR, Warrell D, Kuch U, Chappuis F. Dose of antivenom for the treatment of snakebite with neurotoxic envenoming: Evidence from a randomised controlled trial in Nepal. PLoS Negl Trop Dis 2017; 11:e0005612. [PMID: 28510574 PMCID: PMC5446183 DOI: 10.1371/journal.pntd.0005612] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 05/26/2017] [Accepted: 04/28/2017] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Currently, there is inadequate evidence on which to base clinical management of neurotoxic snakebite envenoming, especially in the choice of initial antivenom dosage. This randomised controlled trial compared the effectiveness and safety of high versus low initial antivenom dosage in victims of neurotoxic envenoming. METHODOLOGY/ PRINCIPAL FINDINGS This was a balanced, randomised, double-blind trial that was conducted in three health care centers located in the Terai plains of Nepal. Participants received either low (two vials) or high (10 vials) initial dosage of Indian polyvalent antivenom. The primary composite outcome consisted of death, the need for assisted ventilation and worsening/recurrence of neurotoxicity. Hourly evaluations followed antivenom treatment. Between April 2011 and October 2012, 157 snakebite victims were enrolled, of which 154 were analysed (76 in the low and 78 in the high initial dose group). Sixty-seven (43·5%) participants met the primary outcome definition. The proportions were similar in the low (37 or 48.7%) vs. high (30 or 38.5%) initial dose group (difference = 10·2%, 95%CI [-6·7 to 27·1], p = 0·264). The mean number of vials used was similar between treatment groups. Overall, patients bitten by kraits did worse than those bitten by cobras. The occurrence of treatment-related adverse events did not differ among treatment groups. A total of 19 serious adverse events occurred, including seven attributed to antivenom. CONCLUSIONS This first robust trial investigating antivenom dosage for neurotoxic snakebite envenoming shows that the antivenom currently used in Nepal performs poorly. Although the high initial dose regimen is not more effective than the low initial dose, it offers the practical advantage of being a single dose, while not incurring higher consumption or enhanced risk of adverse reaction. The development of new and more effective antivenoms that better target the species responsible for bites in the region will help improve future patients' outcomes. TRIAL REGISTRATION The study was registered on clinicaltrials.gov (NCT01284855) (GJ 5/1).
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Affiliation(s)
- Emilie Alirol
- Division of Tropical and Humanitarian Medicine, University Hospitals of Geneva, Geneva, Switzerland
| | | | - Anup Ghimire
- B.P. Koirala Institute of Health Sciences, Dharan, Nepal
| | - Antoine Poncet
- Clinical Research Centre, University Hospitals of Geneva, Geneva, Switzerland
| | | | | | | | | | - Walter Robert Taylor
- Division of Tropical and Humanitarian Medicine, University Hospitals of Geneva, Geneva, Switzerland
- Mahidol Oxford Research Unit, Bangkok, Thailand
| | - David Warrell
- Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom
| | - Ulrich Kuch
- Institute of Occupational Medicine, Social Medicine and Environmental Medicine, Goethe University, Frankfurt am Main, Germany
| | - François Chappuis
- Division of Tropical and Humanitarian Medicine, University Hospitals of Geneva, Geneva, Switzerland
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Harrison RA, Gutiérrez JM. Priority Actions and Progress to Substantially and Sustainably Reduce the Mortality, Morbidity and Socioeconomic Burden of Tropical Snakebite. Toxins (Basel) 2016; 8:toxins8120351. [PMID: 27886134 PMCID: PMC5198546 DOI: 10.3390/toxins8120351] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 11/09/2016] [Accepted: 11/18/2016] [Indexed: 11/16/2022] Open
Abstract
The deliberations and conclusions of a Hinxton Retreat convened in September 2015, entitled “Mechanisms to reverse the public health neglect of snakebite victims” are reported. The participants recommended that the following priority actions be included in strategies to reduce the global impact of snake envenoming: (a) collection of accurate global snakebite incidence, mortality and morbidity data to underpin advocacy efforts and help design public health campaigns; (b) promotion of (i) public education prevention campaigns; (ii) transport systems to improve access to hospitals and (iii) establishment of regional antivenom-efficacy testing facilities to ensure antivenoms’ effectiveness and safety; (c) exploration of funding models for investment in the production of antivenoms to address deficiencies in some regions; (d) establishment of (i) programs for training in effective first aid, hospital management and post-treatment care of victims; (ii) a clinical network to generate treatment guidelines and (iii) a clinical trials system to improve the clinical management of snakebite; (e) development of (i) novel treatments of the systemic and local tissue-destructive effects of envenoming and (ii) affordable, simple, point-of-care snakebite diagnostic kits to improve the accuracy and rapidity of treatment; (f) devising and implementation of interventions to help the people and communities affected by physical and psychological sequelae of snakebite.
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Affiliation(s)
- Robert A Harrison
- Alistair Reid Venom Research Unit, Liverpool School of Tropical, Liverpool L35QA, UK.
| | - José María Gutiérrez
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José 11501-2060, Costa Rica.
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Lewin M, Samuel S, Merkel J, Bickler P. Varespladib (LY315920) Appears to Be a Potent, Broad-Spectrum, Inhibitor of Snake Venom Phospholipase A2 and a Possible Pre-Referral Treatment for Envenomation. Toxins (Basel) 2016; 8:toxins8090248. [PMID: 27571102 PMCID: PMC5037474 DOI: 10.3390/toxins8090248] [Citation(s) in RCA: 139] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 08/11/2016] [Accepted: 08/15/2016] [Indexed: 01/07/2023] Open
Abstract
Snakebite remains a neglected medical problem of the developing world with up to 125,000 deaths each year despite more than a century of calls to improve snakebite prevention and care. An estimated 75% of fatalities from snakebite occur outside the hospital setting. Because phospholipase A2 (PLA2) activity is an important component of venom toxicity, we sought candidate PLA2 inhibitors by directly testing drugs. Surprisingly, varespladib and its orally bioavailable prodrug, methyl-varespladib showed high-level secretory PLA2 (sPLA2) inhibition at nanomolar and picomolar concentrations against 28 medically important snake venoms from six continents. In vivo proof-of-concept studies with varespladib had striking survival benefit against lethal doses of Micrurus fulvius and Vipera berus venom, and suppressed venom-induced sPLA2 activity in rats challenged with 100% lethal doses of M. fulvius venom. Rapid development and deployment of a broad-spectrum PLA2 inhibitor alone or in combination with other small molecule inhibitors of snake toxins (e.g., metalloproteases) could fill the critical therapeutic gap spanning pre-referral and hospital setting. Lower barriers for clinical testing of safety tested, repurposed small molecule therapeutics are a potentially economical and effective path forward to fill the pre-referral gap in the setting of snakebite.
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Affiliation(s)
- Matthew Lewin
- Research and Development, Ophirex, Inc., Corte Madera, CA 94925, USA.
- Center for Exploration and Travel Health, California Academy of Sciences, San Francisco, CA 94118, USA.
| | - Stephen Samuel
- General Medicine, Queen Elizabeth Hospital, King's Lynn, Norfolk PE30 4ET, UK.
| | - Janie Merkel
- Yale Center for Molecular Discovery, Yale University, West Haven, CT 06516, USA.
| | - Philip Bickler
- Anesthesia and Perioperative Care, University of California, San Francisco, CA 94143, USA.
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Calvete JJ, Arias AS, Rodríguez Y, Quesada-Bernat S, Sánchez LV, Chippaux JP, Pla D, Gutiérrez JM. Preclinical evaluation of three polyspecific antivenoms against the venom of Echis ocellatus: Neutralization of toxic activities and antivenomics. Toxicon 2016; 119:280-8. [PMID: 27377229 DOI: 10.1016/j.toxicon.2016.06.022] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Revised: 06/23/2016] [Accepted: 06/30/2016] [Indexed: 01/26/2023]
Abstract
Snakebite envenoming has a heavy burden in the public health in sub-Saharan Africa. The viperid species Echis ocellatus (carpet viper or saw-scaled viper) is the medically most important snake in the savannahs of western sub-Saharan Africa. Several antivenoms are being distributed and used in this region for the treatment of envenomings by E. ocellatus, but the preclinical efficacy of some of these antivenoms has not been assessed. The present study evaluated the preclinical efficacy against E. ocellatus venom of three polyspecific antivenoms: (a) Snake Venom Antiserum (Pan Africa), manufactured by Premium Serums and Vaccines (India); (b) Snake Venom Antiserum (Africa), manufactured by VINS Bioproducts (India); and (c) Antivipmyn(®) Africa, manufactured by Instituto Bioclon (Mexico). Antivenomics analysis revealed the ability of the three antivenoms to immunocapture the majority of components of the venoms of E. ocellatus from Cameroon, Nigeria and Mali, although their maximal immunocapturing capability varied. Bioclon and Premium Serums antivenoms were effective in the neutralization of lethal, hemorrhagic and in vitro coagulant activities of the venom of E. ocellatus from Cameroon, albeit with different potencies. VINS antivenom neutralized hemorrhagic activity of this venom, but failed to neutralize lethality at the highest antivenom dose tested, and had a low neutralizing efficacy against in vitro coagulant effect.
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Affiliation(s)
- Juan J Calvete
- Laboratorio de Venómica Estructural y Funcional, Instituto de Biomedicina de Valencia, CSIC, Valencia, Spain.
| | - Ana Silvia Arias
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
| | - Yania Rodríguez
- Laboratorio de Venómica Estructural y Funcional, Instituto de Biomedicina de Valencia, CSIC, Valencia, Spain
| | - Sarai Quesada-Bernat
- Laboratorio de Venómica Estructural y Funcional, Instituto de Biomedicina de Valencia, CSIC, Valencia, Spain
| | - Laura V Sánchez
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
| | - Jean Philippe Chippaux
- Institut de Recherche pour le Développement, UMR MERIT "Mother and Child Facing Tropical Diseases", Cotonou, Benin; Université Paris Descartes, Sorbonne Paris Cité, Faculté de Pharmacie, Avenue de l'Observatoire, Paris, France
| | - Davinia Pla
- Laboratorio de Venómica Estructural y Funcional, Instituto de Biomedicina de Valencia, CSIC, Valencia, Spain.
| | - José María Gutiérrez
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica.
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Antivenom Costs Show Need for Education and Collaborative Efforts. Am J Med 2016; 129:e29. [PMID: 27215992 DOI: 10.1016/j.amjmed.2015.10.042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2015] [Revised: 10/07/2015] [Accepted: 10/07/2015] [Indexed: 11/20/2022]
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