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Alfa-Ibrahim Adio A, Malami I, Lawal N, Jega AY, Abubakar B, Bello MB, Ibrahim KG, Abubakar MB, Abdussamad A, Imam MU. Neurotoxic snakebites in Africa: Clinical implications, therapeutic strategies, and antivenom efficacy. Toxicon 2024; 247:107811. [PMID: 38917892 DOI: 10.1016/j.toxicon.2024.107811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2024] [Revised: 05/23/2024] [Accepted: 06/16/2024] [Indexed: 06/27/2024]
Abstract
Snakebite is a significant health concern in Africa, particularly due to neurotoxic envenomation which can lead to neuromuscular paralysis and respiratory failure. In Nigeria, snakes from the Elapidae family are a notable cause of envenomation cases, though these incidents are underreported. This review examined case reports of neurotoxic envenomation in Africa, highlighting the clinical impacts and the efficacy of available antivenoms. Preclinical studies showed that the polyvalent antivenom from the South African Institute for Medical Research (SAIMR) was highly effective against neurotoxicity with a protective efficacy (R) of 1346.80 mg/mL, while clinical assessment emphasized the need for high-dose antivenom therapy along with supportive measures like mechanical ventilation. Unlike hemorrhagic envenomation, where antivenom promptly resolves bleeding, neurotoxic cases often require additional interventions. The review underscores the necessity for tailored approaches in antivenom therapy to address the complexities of neurotoxic snakebites and reduce their public health burden in Africa.
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Affiliation(s)
- Abdulbaki Alfa-Ibrahim Adio
- Centre for Advanced Medical Research and Training, Usmanu Danfodiyo University, Sokoto, Nigeria; Department of Biochemistry and Molecular Biology, Faculty of Chemical and Life Sciences, Usmanu Danfodiyo University, Sokoto, Nigeria
| | - Ibrahim Malami
- Centre for Advanced Medical Research and Training, Usmanu Danfodiyo University, Sokoto, Nigeria; Department of Pharmacognosy and Ethnopharmacy, Faculty of Pharmaceutical Sciences, Usmanu Danfodiyo University, Sokoto, Nigeria
| | - Nafiu Lawal
- Centre for Advanced Medical Research and Training, Usmanu Danfodiyo University, Sokoto, Nigeria; Department of Veterinary Microbiology, Faculty of Veterinary Medicine, Usmanu Danfodiyo University, Sokoto, Nigeria
| | - Amina Yusuf Jega
- Department of Pharmaceutical and Medicinal Chemistry, Faculty of Pharmaceutical Sciences, Usmanu Danfodiyo University, Sokoto, Nigeria
| | - Bilyaminu Abubakar
- Centre for Advanced Medical Research and Training, Usmanu Danfodiyo University, Sokoto, Nigeria; Department of Pharmacology and Toxicology, Faculty of Pharmaceutical Sciences, Usmanu Danfodiyo University, Sokoto, Nigeria
| | - Muhammad Bashir Bello
- Centre for Advanced Medical Research and Training, Usmanu Danfodiyo University, Sokoto, Nigeria; Department of Veterinary Microbiology, Faculty of Veterinary Medicine, Usmanu Danfodiyo University, Sokoto, Nigeria; Vaccine Development Unit, Infectious Disease Research Development, King Abdullah International Medical Research Center, Riyadh, Saudi Arabia
| | - Kasimu Ghandi Ibrahim
- Centre for Advanced Medical Research and Training, Usmanu Danfodiyo University, Sokoto, Nigeria; Department of Basic Medical and Dental Sciences, Faculty of Dentistry, Zarqa University, P.O. Box 2000, Zarqa, 13110, Jordan; Department of Physiology, Faculty of Basic Medical Sciences, College of Health Sciences, Usmanu Danfodiyo University, Sokoto, Nigeria
| | - Murtala Bello Abubakar
- Centre for Advanced Medical Research and Training, Usmanu Danfodiyo University, Sokoto, Nigeria; Department of Physiology, Faculty of Basic Medical Sciences, College of Health Sciences, Usmanu Danfodiyo University, Sokoto, Nigeria
| | - Abdussamad Abdussamad
- Department of Veterinary Physiology and Biochemistry, Faculty of Veterinary Medicine, Bayero University, Kano, Nigeria
| | - Mustapha Umar Imam
- Centre for Advanced Medical Research and Training, Usmanu Danfodiyo University, Sokoto, Nigeria; Department of Medical Biochemistry, Faculty of Basic Medical Sciences, College of Health Sciences, Usmanu Danfodiyo University, Sokoto, Nigeria.
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Rodríguez-Vargas A, Franco-Vásquez AM, Bolívar-Barbosa JA, Vega N, Reyes-Montaño E, Arreguín-Espinosa R, Carbajal-Saucedo A, Angarita-Sierra T, Ruiz-Gómez F. Unveiling the Venom Composition of the Colombian Coral Snakes Micrurus helleri, M. medemi, and M. sangilensis. Toxins (Basel) 2023; 15:622. [PMID: 37999485 PMCID: PMC10674450 DOI: 10.3390/toxins15110622] [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: 06/23/2023] [Revised: 08/10/2023] [Accepted: 08/16/2023] [Indexed: 11/25/2023] Open
Abstract
Little is known of the biochemical composition and functional features of the venoms of poorly known Colombian coral snakes. Here, we provide a preliminary characterization of the venom of two Colombian endemic coral snake species, Micrurus medemi and M. sangilensis, as well as Colombian populations of M. helleri. Electrophoresis and RP-HPLC techniques were used to identify venom components, and assays were conducted to detect enzyme activities, including phospholipase A2, hyaluronidase, and protease activities. The median lethal dose was determined using murine models. Cytotoxic activities in primary cultures from hippocampal neurons and cancer cell lines were evaluated. The venom profiles revealed similarities in electrophoretic separation among proteins under 20 kDa. The differences in chromatographic profiles were significant, mainly between the fractions containing medium-/large-sized and hydrophobic proteins; this was corroborated by a proteomic analysis which showed the expected composition of neurotoxins from the PLA2 (~38%) and 3FTx (~17%) families; however, a considerable quantity of metalloproteinases (~12%) was detected. PLA2 activity and protease activity were higher in M. helleri venom according to qualitative and quantitative assays. M. medemi venom had the highest lethality. All venoms decreased cell viability when tested on tumoral cell cultures, and M. helleri venom had the highest activity in neuronal primary culture. These preliminary studies shed light on the venoms of understudied coral snakes and broaden the range of sources that could be used for subsequent investigations of components with applications to specific diseases. Our findings also have implications for the clinical manifestations of snake envenoming and improvements in its medical management.
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Affiliation(s)
- Ariadna Rodríguez-Vargas
- Grupo de Investigación en Proteínas, Departamento de Química, Faculty of Sciences, Universidad Nacional de Colombia, Bogotá 11001, Colombia (N.V.); (E.R.-M.)
- Grupo de Investigación en Animales Ponzoñosos y sus Venenos, Dirección de Producción, Instituto Nacional de Salud, Bogotá 111321, Colombia; (T.A.-S.); (F.R.-G.)
| | - Adrián Marcelo Franco-Vásquez
- Departamento de Química de Biomacromoléculas, Instituto de Química, Universidad Nacional Autónoma de México, Coyoacán, Ciudad de México 04510, Mexico (R.A.-E.)
| | - Janeth Alejandra Bolívar-Barbosa
- Grupo de Investigación en Proteínas, Departamento de Química, Faculty of Sciences, Universidad Nacional de Colombia, Bogotá 11001, Colombia (N.V.); (E.R.-M.)
| | - Nohora Vega
- Grupo de Investigación en Proteínas, Departamento de Química, Faculty of Sciences, Universidad Nacional de Colombia, Bogotá 11001, Colombia (N.V.); (E.R.-M.)
| | - Edgar Reyes-Montaño
- Grupo de Investigación en Proteínas, Departamento de Química, Faculty of Sciences, Universidad Nacional de Colombia, Bogotá 11001, Colombia (N.V.); (E.R.-M.)
| | - Roberto Arreguín-Espinosa
- Departamento de Química de Biomacromoléculas, Instituto de Química, Universidad Nacional Autónoma de México, Coyoacán, Ciudad de México 04510, Mexico (R.A.-E.)
| | - Alejandro Carbajal-Saucedo
- Laboratorio de Herpetología, Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo León, San Nicolás de los Garza 66450, Mexico;
| | - Teddy Angarita-Sierra
- Grupo de Investigación en Animales Ponzoñosos y sus Venenos, Dirección de Producción, Instituto Nacional de Salud, Bogotá 111321, Colombia; (T.A.-S.); (F.R.-G.)
- Grupo de investigación Biodiversidad para la Sociedad, Escuela de pregrados, Dirección Académica, Universidad Nacional de Colombia sede de La Paz, Cesar 22010, Colombia
| | - Francisco Ruiz-Gómez
- Grupo de Investigación en Animales Ponzoñosos y sus Venenos, Dirección de Producción, Instituto Nacional de Salud, Bogotá 111321, Colombia; (T.A.-S.); (F.R.-G.)
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Cherif MS, Keita M, Dahal P, Guilavogui T, Beavogui AH, Diassy L, Conde M, Touré A, Delamou A. Neglected tropical diseases in Republic of Guinea: disease endemicity, case burden and the road towards the 2030 target. Int Health 2023; 15:490-504. [PMID: 37232124 PMCID: PMC10472893 DOI: 10.1093/inthealth/ihad036] [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: 07/07/2022] [Revised: 03/02/2023] [Accepted: 05/01/2023] [Indexed: 05/27/2023] Open
Abstract
Neglected tropical diseases (NTDs) predominantly affect vulnerable and marginalized populations in tropical and subtropical areas and globally affect more than one billion people. In Guinea, the burden of NTDs is estimated to be >7.5 disability-adjusted life years per million inhabitants. Currently the Guinea NTDs master plan (2017-2020) has identified eight diseases as public health problems: onchocerciasis, lymphatic filariasis, trachoma, schistosomiasis and soil-transmitted helminthiasis, leprosy, human African trypanosomiasis and Buruli ulcer. In this review we discuss the past and the current case burden of the priority NTDs in Guinea, highlight the major milestones and discuss current and future areas of focus for achieving the 2030 target outlined by the World Health Organization.
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Affiliation(s)
- Mahamoud Sama Cherif
- Faculty of Sciences and Health Technics, Gamal Abdel Nasser University of Conakry, Conakry, Guinea
- Direction Regionale de la Santé de Faranah, Ministère de la santé et de l'hygiène publique, Faranah, Guinea
- Service de Pediatrie, Hospital National Ignace Deen, Ministère de la santé et de l'Hygiène Publique, Conakry, Guinea
| | - Mory Keita
- World Health Organization, Regional Office for the Eastern Mediterranean, Cairo, Egypt
- Institute of Global Health, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Prabin Dahal
- Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK
| | - Timothé Guilavogui
- Management and Programmes Coordination, Ministry of Health, Conakry, Guinea
| | - Abdoul Habib Beavogui
- Faculty of Sciences and Health Technics, Gamal Abdel Nasser University of Conakry, Conakry, Guinea
- Centre National de Formation et Recherche en Sante Rurale de Maferinyah, Maferinyah, Guinea
| | - Lamine Diassy
- World Health Organization, Guinea office, Landreah, Corniche Nord, Boîte postale 817, Conakry, Guinea
| | - Mohamed Conde
- Service de Pediatrie, Hospital National Ignace Deen, Ministère de la santé et de l'Hygiène Publique, Conakry, Guinea
| | - Abdoulaye Touré
- Faculty of Sciences and Health Technics, Gamal Abdel Nasser University of Conakry, Conakry, Guinea
- Institut National de Santé Publique, Ministère de la Santé et de l'Hygiène Publique, Conakry, Guinea
| | - Alexandre Delamou
- Faculty of Sciences and Health Technics, Gamal Abdel Nasser University of Conakry, Conakry, Guinea
- Centre National de Formation et Recherche en Sante Rurale de Maferinyah, Maferinyah, Guinea
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Warrell DA, Williams DJ. Clinical aspects of snakebite envenoming and its treatment in low-resource settings. Lancet 2023; 401:1382-1398. [PMID: 36931290 DOI: 10.1016/s0140-6736(23)00002-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 11/26/2022] [Accepted: 12/18/2022] [Indexed: 03/16/2023]
Abstract
There is increasing recognition of the public health importance of snakebite envenoming. Worldwide annual incidence is likely to be 5 million bites, with mortality exceeding 150 000 deaths, and the resulting physical and psychological morbidity leads to substantial social and economic repercussions. Prevention through community education by trained health workers is the most effective and economically viable strategy for reducing risk of bites and envenoming. Clinical challenges to effective treatment are most substantial in rural areas of low-resource settings, where snakebites are most common. Classic skills of history taking, physical examination, and use of affordable point-of-care tests should be followed by monitoring of evolving local and systemic envenoming. Despite the profusion of new ideas for interventions, hyperimmune equine or ovine plasma-derived antivenoms remain the only specific treatment for snakebite envenoming. The enormous interspecies and intraspecies complexity and diversity of snake venoms, revealed by modern venomics, demands a radical redesign of many current antivenoms.
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Affiliation(s)
- David A Warrell
- Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK; Experimental Medicine Division, John Radcliffe Hospital, Headington, UK.
| | - David J Williams
- Regulation and Prequalification Department, World Health Organization, Geneva, Switzerland
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Romo E, Torres M, Martin-Solano S. Current situation of snakebites envenomation in the Neotropics: Biotechnology, a versatile tool in the production of antivenoms. BIONATURA 2022. [DOI: 10.21931/rb/2022.07.04.54] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Snakebite envenomation is a neglected tropical disease that affects millions of people around the world with a great impact on health and the economy. Unfortunately, public health programs do not include this kind of disease as a priority in their social programs. Cases of snakebite envenomations in the Neotropics are inaccurate due to inadequate disease management from medical records to the choice of treatments. Victims of snakebite envenomation are primarily found in impoverished agricultural areas where remote conditions limit the availability of antivenom. Antivenom serum is the only Food and Drug Administration-approved treatment used up to date. However, it has several disadvantages in terms of safety and effectiveness. This review provides a comprehensive insight dealing with the current epidemiological status of snakebites in the Neotropics and technologies employed in antivenom production. Also, modern biotechnological tools such as transcriptomic, proteomic, immunogenic, high-density peptide microarray and epitope mapping are highlighted for producing new-generation antivenom sera. These results allow us to propose strategic solutions in the Public Health Sector for managing this disease.
Keywords: antivenom, biotechnology, neglected tropical disease, omics, recombinant antibody.
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Affiliation(s)
- Elizabeth Romo
- Carrera de Ingeniería en Biotecnología, Departamento de Ciencias de la Vida y la Agricultura, Universidad de las Fuerzas Armadas-ESPE, Sangolquí, Ecuador
| | - Marbel Torres
- Carrera de Ingeniería en Biotecnología, Departamento de Ciencias de la Vida y la Agricultura, Universidad de las Fuerzas Armadas-ESPE, Sangolquí, Ecuador, Grupo de Investigación en Sanidad Animal y Humana (GISAH), Carrera de Ingeniería en Biotecnología, Departamento de Ciencias de la Vida y la Agricultura, Universidad de las Fuerzas Armadas-ESPE, Immunology and Virology Laboratory, Nanoscience and Nanotechnology Center, Universidad de las Fuerzas Armadas, ESPE, Sangolquí, Ecuador
| | - Sarah Martin-Solano
- Carrera de Ingeniería en Biotecnología, Departamento de Ciencias de la Vida y la Agricultura, Universidad de las Fuerzas Armadas-ESPE, Sangolquí, Ecuador, Grupo de Investigación en Sanidad Animal y Humana (GISAH), Carrera de Ingeniería en Biotecnología, Departamento de Ciencias de la Vida y la Agricultura, Universidad de las Fuerzas Armadas-ESPE, Grupo de Investigación en Biodiversidad, Zoonosis y Salud Pública, Universidad Central del Ecuador
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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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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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Benjamin JM, Abo BN, Brandehoff N. Review Article: Snake Envenomation in Africa. CURRENT TROPICAL MEDICINE REPORTS 2020. [DOI: 10.1007/s40475-020-00198-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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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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Évaluation de l’efficacité et la tolérance de Inoserp® Panafricain au Sénégal. TOXICOLOGIE ANALYTIQUE ET CLINIQUE 2019. [DOI: 10.1016/j.toxac.2018.12.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Williams DJ, Habib AG, Warrell DA. Clinical studies of the effectiveness and safety of antivenoms. Toxicon 2018; 150:1-10. [PMID: 29746978 DOI: 10.1016/j.toxicon.2018.05.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 05/01/2018] [Accepted: 05/02/2018] [Indexed: 10/17/2022]
Abstract
In the 1890s, hyperimmune sera proved effective in animals against challenge by the snake venom against which they had been raised. They were first used, apparently successfully, in a human patient in about 1895. Since then, antivenoms have become accepted as the only reliable specific treatment for snake-bite envenoming. Despite decades of accumulated clinical experience and a number of published randomized comparative and observational studies, the clinical effectiveness and safety of some antivenoms remain open to question, due to a lack of robust randomized controlled trial data. Antivenoms in some poorly regulated markets may have high rates of potentially fatal adverse effects and their use must be balanced by demonstrable effectiveness. Even those manufactured to strict regulatory requirements may pose a rare risk of severe adverse reactions. Most antivenoms currently marketed around the world were registered without first being studied clinically. There is increasing pressure to subject antivenoms, even those that are long-established, to the same protocols of rigorous pre-clinical and clinical assessment that are standard regulatory requirements for other drugs. Conventional clinical testing progresses through Phases I, II, III to IV. Most authorities consider antivenoms too dangerous to be used in Phase I studies in healthy volunteers. An alternative method for preliminary estimation of safety, dose-finding and effectiveness, is proposed - the "3 + 3" dose escalation or de-escalation design, in volunteer patients, as used in oncology to test cytotoxic drugs. Antivenoms are so widely used and well trusted, that there are few ethical justifications for placebo controls. However, placebo might be ethically justified if there were no proven effective treatment and or if withholding or delaying treatment posed acceptably negligible risks to the participants. Antivenom trials are most urgently needed in low-to middle-income countries where there are many practical, logistical and funding challenges. Basic requirements for clinical trials include identification of the biting species of snake in every case; the use of objective, clinically-relevant endpoints, such as restoration of blood coagulability; definition of inclusion, exclusion and withdrawal criteria; assurance of antivenom safety; ethical considerations; inclusion of one or more control (comparator) groups; and analysis based on intention to treat. The highest quality evidence comes from Phase II and larger Phase III studies that have been designed as statistically powerful, randomized, controlled trials (RCTs), ideally with blinding of patients and investigators to avoid bias. Because of the challenges to carrying out clinical trials of antivenoms, Phase IV trials (post-marketing surveillance) are potentially more important and useful than for most other drugs.
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Affiliation(s)
- David J Williams
- Australian Venom Research Unit, Department of Pharmacology and Therapeutics, University of Melbourne, Parkville, VIC, 3010, Australia; Charles Campbell Toxinology Centre, School of Medicine and Health Sciences, University of Papua New Guinea, Boroko, NCD, 121, Papua New Guinea.
| | - Abdulrazaq G Habib
- Department of Medicine, Bayero University Kano, Aminu Kano Teaching Hospital, PMB 3452, Kano, Nigeria.
| | - David A Warrell
- Australian Venom Research Unit, Department of Pharmacology and Therapeutics, University of Melbourne, Parkville, VIC, 3010, Australia; Nuffield Department of Clinical Medicine, University of Oxford, Oxford OX3 9DU, UK.
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Baudou FG, Litwin S, Lanari LC, Laskowicz RD, Damin CF, Chippaux JP, de Roodt AR. Antivenom against Crotalus durissus terrificus venom: Immunochemical reactivity and experimental neutralizing capacity. Toxicon 2017; 140:11-17. [DOI: 10.1016/j.toxicon.2017.10.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 09/16/2017] [Accepted: 10/13/2017] [Indexed: 11/24/2022]
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Barbosa AN, Boyer L, Chippaux JP, Medolago NB, Caramori CA, Paixão AG, Poli JPV, Mendes MB, dos Santos LD, Ferreira RS, Barraviera B. A clinical trial protocol to treat massive Africanized honeybee ( Apis mellifera) attack with a new apilic antivenom. J Venom Anim Toxins Incl Trop Dis 2017; 23:14. [PMID: 28331487 PMCID: PMC5356296 DOI: 10.1186/s40409-017-0106-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 03/07/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Envenomation caused by multiple stings from Africanized honeybees Apis mellifera constitutes a public health problem in the Americas. In 2015, the Brazilian Ministry of Health reported 13,597 accidents (incidence of seven cases per 100,000 inhabitants) with 39 deaths (lethality of 0.25%). The toxins present in the venom, which include melittin and phospholipase A2, cause lesions in diverse organs and systems that may be fatal. As there has been no specific treatment to date, management has been symptomatic and supportive only. METHODS In order to evaluate the safety and neutralizing capacity of a new apilic antivenom, as well as to confirm its lowest effective dose, a clinical protocol was developed to be applied in a multicenter, non-randomized and open phase I/II clinical trial. Twenty participants with more than five stings, aged more than 18 years, of both sexes, who have not previously received the heterologous serum against bee stings, will be included for 24 months. The proposed dose was based on the antivenom neutralizing capacity and the number of stings. Treatment will be administered only in a hospital environment and the participants will be evaluated for a period up to 30 days after discharge for clinical and laboratory follow-up. RESULTS This protocol, approved by the Brazilian regulatory agencies for ethics (National Commission for Ethics on Research - CONEP) and sanitation (National Health Surveillance Agency - ANVISA), is a guideline constituted by specific, adjuvant, symptomatic and complementary treatments, in addition to basic orientations for conducting a clinical trial involving heterologous sera. CONCLUSIONS This is the first clinical trial protocol designed specifically to evaluate the preliminary efficacy and safety of a new antivenom against stings from the Africanized honeybee Apis mellifera. The results will support future studies to confirm a new treatment for massive bee attack that has a large impact on public health in the Americas.
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Affiliation(s)
- Alexandre Naime Barbosa
- Department of Tropical Diseases, Botucatu Medical School, São Paulo State University (UNESP – Univ Estadual Paulista), Botucatu, SP Brazil
| | - Leslie Boyer
- VIPER Institute, University of Arizona College of Medicine, Tucson, AZ USA
| | - Jean-Philippe Chippaux
- CERPAGE, Faculté des Sciences de la Santé, Université d’Abomey-Calavi, Cotonou, Benin
- UMR216, Mère et enfant face aux infections tropicales and PRES Sorbonne Paris Cité, Faculté de Pharmacie, Université Paris Descartes, Paris, France
| | - Natalia Bronzatto Medolago
- Clinical Research Unit (UPECLIN), Botucatu Medical School, São Paulo State University (UNESP – Univ Estadual Paulista), Botucatu, SP Brazil
| | - Carlos Antonio Caramori
- Department of Internal Medicine, Botucatu Medical School, São Paulo State University (UNESP - Univ Estadual Paulista), Botucatu, SP Brazil
| | - Ariane Gomes Paixão
- Department of Tropical Diseases, Botucatu Medical School, São Paulo State University (UNESP – Univ Estadual Paulista), Botucatu, SP Brazil
| | - João Paulo Vasconcelos Poli
- Department of Tropical Diseases, Botucatu Medical School, São Paulo State University (UNESP – Univ Estadual Paulista), Botucatu, SP Brazil
| | - Mônica Bannwart Mendes
- Department of Tropical Diseases, Botucatu Medical School, São Paulo State University (UNESP – Univ Estadual Paulista), Botucatu, SP Brazil
| | - Lucilene Delazari dos Santos
- Center for the Study of Venoms and Venomous Animals, São Paulo State University (UNESP – Univ Estadual Paulista), Av. José Barbosa de Barros, 1780, Fazenda Experimental Lageado, Botucatu, SP CEP 18.610-307 Brazil
| | - Rui Seabra Ferreira
- Department of Tropical Diseases, Botucatu Medical School, São Paulo State University (UNESP – Univ Estadual Paulista), Botucatu, SP Brazil
- Center for the Study of Venoms and Venomous Animals, São Paulo State University (UNESP – Univ Estadual Paulista), Av. José Barbosa de Barros, 1780, Fazenda Experimental Lageado, Botucatu, SP CEP 18.610-307 Brazil
| | - Benedito Barraviera
- Department of Tropical Diseases, Botucatu Medical School, São Paulo State University (UNESP – Univ Estadual Paulista), Botucatu, SP Brazil
- Center for the Study of Venoms and Venomous Animals, São Paulo State University (UNESP – Univ Estadual Paulista), Av. José Barbosa de Barros, 1780, Fazenda Experimental Lageado, Botucatu, SP CEP 18.610-307 Brazil
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Cañas CA, Castro-Herrera F, Castaño-Valencia S. Envenomation by the red-tailed coral snake ( Micrurus mipartitus) in Colombia. J Venom Anim Toxins Incl Trop Dis 2017; 23:9. [PMID: 28228775 PMCID: PMC5307858 DOI: 10.1186/s40409-017-0100-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 02/04/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Although the red-tailed coral snake (Micrurus mipartitus) is widely distributed in Colombia and its venom is highly neurotoxic and life threatening, envenomation by this species is rare. Therefore, this report may shed some light on the clinical presentation of M. mipartitus bites. CASE PRESENTATIONS Herein, we describe two cases of patients bitten by red-tailed coral snakes, illustrating the clinical presentation of the victims, the outcomes and treatment provided. CONCLUSION Envenomation caused by M. mipartitus provokes predicable neurotoxicity, and its treatment should be based on respiratory support and use of specific antivenom.
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Affiliation(s)
- Carlos A Cañas
- Department of Internal Medicine, Fundación Valle del Lili, Universidad Icesi, Cali, Colombia
| | - Fernando Castro-Herrera
- Department of Physiological Sciences, School of Health Sciences, Universidad del Valle, Cali, Colombia
| | - Santiago Castaño-Valencia
- Department of Physiological Sciences, School of Health Sciences, Universidad del Valle, Cali, Colombia
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15
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Hamza M, Idris MA, Maiyaki MB, Lamorde M, Chippaux JP, Warrell DA, Kuznik A, Habib AG. Cost-Effectiveness of Antivenoms for Snakebite Envenoming in 16 Countries in West Africa. PLoS Negl Trop Dis 2016; 10:e0004568. [PMID: 27027633 PMCID: PMC4814077 DOI: 10.1371/journal.pntd.0004568] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 03/02/2016] [Indexed: 12/02/2022] Open
Abstract
Background Snakebite poisoning is a significant medical problem in agricultural societies in Sub Saharan Africa. Antivenom (AV) is the standard treatment, and we assessed the cost-effectiveness of making it available in 16 countries in West Africa. Methods We determined the cost-effectiveness of AV based on a decision-tree model from a public payer perspective. Specific AVs included in the model were Antivipmyn, FAV Afrique, EchiTab-G and EchiTab-Plus. We derived inputs from the literature which included: type of snakes causing bites (carpet viper (Echis species)/non-carpet viper), AV effectiveness against death, mortality without AV, probability of Early Adverse Reactions (EAR), likelihood of death from EAR, average age at envenomation in years, anticipated remaining life span and likelihood of amputation. Costs incurred by the victims include: costs of confirming and evaluating envenomation, AV acquisition, routine care, AV transportation logistics, hospital admission and related transportation costs, management of AV EAR compared to the alternative of free snakebite care with ineffective or no AV. Incremental Cost Effectiveness Ratios (ICERs) were assessed as the cost per death averted and the cost per Disability-Adjusted-Life-Years (DALY) averted. Probabilistic Sensitivity Analyses (PSA) using Monte Carlo simulations were used to obtain 95% Confidence Intervals of ICERs. Results The cost/death averted for the 16 countries of interest ranged from $1,997 in Guinea Bissau to $6,205 for Liberia and Sierra Leone. The cost/DALY averted ranged from $83 (95% Confidence Interval: $36-$240) for Benin Republic to $281 ($159–457) for Sierra-Leone. In all cases, the base-case cost/DALY averted estimate fell below the commonly accepted threshold of one time per capita GDP, suggesting that AV is highly cost-effective for the treatment of snakebite in all 16 WA countries. The findings were consistent even with variations of inputs in 1—way sensitivity analyses. In addition, the PSA showed that in the majority of iterations ranging from 97.3% in Liberia to 100% in Cameroun, Guinea Bissau, Mali, Nigeria and Senegal, our model results yielded an ICER that fell below the threshold of one time per capita GDP, thus, indicating a high degree of confidence in our results. Conclusions Therapy for SBE with AV in countries of WA is highly cost-effective at commonly accepted thresholds. Broadening access to effective AVs in rural communities in West Africa is a priority. Antivenom is the main intervention against snakebite poisoning but is relatively scarce, unaffordable and the situation has been compounded further by the recent cessation of production of effective antivenoms and marketing of inappropriate products. Given this crisis, we assessed the cost effectiveness of providing antivenoms in West Africa by comparing costs associated with antivenom treatment against their health benefits in decreasing mortality. In the most comprehensive analyses ever conducted, it was observed the incremental cost effectiveness ratio of providing antivenom ranged from $1,997 in Guinea Bissau to $6,205 for Liberia and Sierra-Leone per death averted while cost per Disability Adjusted Life Year (DALY) averted ranged from $83 for Benin Republic to $281 for Sierra-Leone. There is probability of 97.3–100% that antivenoms are very cost-effective in the analyses. These demonstrate antivenom is highly cost-effective and compares favorably to other commonly funded healthcare interventions. Providing and broadening antivenom access throughout areas at risk in rural West Africa should be prioritized given the considerable reduction in deaths and DALYs that could be derived at a relatively small cost.
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Affiliation(s)
- Muhammad Hamza
- College of Health of Sciences, Bayero University, Kano, Nigeria
| | - Maryam A. Idris
- College of Health of Sciences, Bayero University, Kano, Nigeria
| | - Musa B. Maiyaki
- College of Health of Sciences, Bayero University, Kano, Nigeria
| | - Mohammed Lamorde
- Infectious Diseases Institute, Makerere University College of Health Sciences, Kampala, Uganda
| | - Jean-Philippe Chippaux
- Institut de Recherche pour le Development, Cotonou, Benin Republic and Université Paris Descartes, Sorbonne Paris Cité, Faculté de Pharmacie, Paris, France
| | - David A. Warrell
- Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Andreas Kuznik
- College of Health of Sciences, Bayero University, Kano, Nigeria
- Infectious Diseases Institute, Makerere University College of Health Sciences, Kampala, Uganda
- Celgene Corporation, Warren, New Jersey, United States of America
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Gampini S, Nassouri S, Chippaux JP, Semde R. Retrospective study on the incidence of envenomation and accessibility to antivenom in Burkina Faso. J Venom Anim Toxins Incl Trop Dis 2016; 22:10. [PMID: 26985188 PMCID: PMC4793557 DOI: 10.1186/s40409-016-0066-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 02/22/2016] [Indexed: 11/29/2022] Open
Abstract
Background Snakebite is a common neglected public health issue, especially in poor rural areas of sub-Saharan Africa, Asia and Latin America. Passive immunotherapy with safe and effective antivenom is the only approved treatment for it. This study aimed to determine the incidence of snakebites, and to assess the availability and accessibility of antivenoms, from 2010 to 2014, in Burkina Faso. Methods The assessment of snakebite cases managed in all health facilities from 2010 to 2014 was performed from the Statistical Yearbook of the Ministry of Health. Antivenom consumption data were collected from the drug wholesalers established in Burkina Faso. Results Snakebites are among the five leading causes of consultations in health districts. From 2010 to 2014, 114,126 envenomation cases occurred in Burkina Faso, out of which 62,293 (54.6 %) victims have been hospitalized resulting in 1,362 (2 %) deaths. The annual incidence and mortality were respectively 130 bites and 1.75 deaths per 100,000 inhabitants. The amount of antivenom sold by wholesalers were 5,738 vials with a total cost of US$ 539,055 (annual average = US$ 107,811). The high cost of these antivenoms (between US$ 42 and 170 per dose according to brand) limited their use by rural people, the main victims of snakebites, whose income is insufficient. Thus, only 4 % of patients received antivenom treatment over the past five years. The price of antivenom was reduced in 2015 to US$ 3.4 by a public drug wholesaler. Conclusion The study confirmed the high burden of snakebites in Burkina Faso. To better manage envenomation, Burkina Faso implemented a strategy consisting in seeking affordable sources of antivenom supply of good quality and innovative mechanisms of subsidy.
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Affiliation(s)
- Sandrine Gampini
- Ministère de la Santé, Direction générale de la pharmacie du médicament et des laboratoires, 03 BP 7009 Ouagadougou 03, Kadiogo Burkina Faso
| | - Sonia Nassouri
- Ministère de la Santé, Direction générale de la pharmacie du médicament et des laboratoires, 03 BP 7009 Ouagadougou 03, Kadiogo Burkina Faso
| | - Jean-Philippe Chippaux
- UMR 216, Mère et enfant face aux infections tropicales, Institut de Recherche pour le Développement, Cotonou, Bénin ; Université Paris Descartes, Sorbonne Paris Cité, Faculté de Pharmacie, Paris, France
| | - Rasmané Semde
- Ministère de la Santé, Direction générale de la pharmacie du médicament et des laboratoires, 03 BP 7009 Ouagadougou 03, Kadiogo Burkina Faso ; Département des Sciences Pharmaceutiques, Université de Ouagadougou, Ouagadougou, Burkina Faso
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Leong PK, Fung SY, Tan CH, Sim SM, Tan NH. Immunological cross-reactivity and neutralization of the principal toxins of Naja sumatrana and related cobra venoms by a Thai polyvalent antivenom (Neuro Polyvalent Snake Antivenom). Acta Trop 2015; 149:86-93. [PMID: 26026717 DOI: 10.1016/j.actatropica.2015.05.020] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Revised: 04/23/2015] [Accepted: 05/25/2015] [Indexed: 10/23/2022]
Abstract
The low potency of cobra antivenom has been an area of concern in immunotherapy for cobra envenomation. This study sought to investigate factors limiting the neutralizing potency of cobra antivenom, using a murine model. We examined the immunological reactivity and neutralizing potency of a Thai polyvalent antivenom against the principal toxins of Naja sumatrana (Equatorial spitting cobra) venom and two related Asiatic cobra venom α-neurotoxins. The antivenom possesses moderate neutralizing potency against phospholipases A2 (P, potency of 0.98mg/mL) and moderately weak neutralizing potency against long-chain α-neurotoxins (0.26-0.42mg/mL) but was only weakly effective in neutralizing the short-chain α-neurotoxins and cardiotoxins (0.05-0.08mg/mL). The poor neutralizing potency of the antivenom on the low molecular mass short-chain neurotoxins and cardiotoxins is presumably the main limiting factor of the efficacy of the cobra antivenom. Our results also showed that phospholipase A2, which exhibited the highest ELISA reactivity and avidity, was most effectively neutralized, whereas N. sumatrana short-chain neurotoxin, which exhibited the lowest ELISA reactivity and avidity, was least effectively neutralized by the antivenom. These observations suggest that low immunoreactivity (low ELISA reactivity and avidity) is one of the reasons for poor neutralization of the cobra venom low molecular mass toxins. Nevertheless, the overall results show that there is a lack of congruence between the immunological reactivity of the toxins toward antivenom and the effectiveness of toxin neutralization by the antivenom, indicating that there are other factors that also contribute to the weak neutralization capacity of the antivenom. Several suggestions have been put forward to overcome the low efficacy of the cobra antivenom. The use of a 'proper-mix' formulation of cobra venoms as immunogen, whereby the immunogen mixture used for hyperimmunization contains a mix of various types of α-neurotoxins and cardiotoxins in sufficient amount, may also help to improve the efficacy and broaden the neutralization spectrum of the antivenom.
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