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

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

Anti-Snake Venom Properties of Medicinal Plants: A Comprehensive Systematic Review of Literature

Abstract Snakebite is one of the major health issues posing considerable morbidity and mortality. According to an estimate of World Health Organization (WHO) (World health organization, 2021) approximately 5 million people are bitten by several species of snakes resulting in up to 2.5 million envenomation cases annually. The mainstay of treatment for envenomation is intravenous administration of anti-snake venom. Although antivenom neutralizes the systemic effects but it does not relieve the symptoms such as venom-induced hemorrhage, necrosis and nephrotoxicity. Moreover, the use of antivenoms is associated with hypersensitivity reactions including urticaria, anaphylaxis, or serum sickness due to their heterologous property. Furthermore, stringent storage conditions and narrow specificity of antivenoms limit their use in both developed as well as developing countries. In this context, researchers have been searching for natural products and plant extracts to explore their antivenom activity along with anti-myotoxic, anti-hemorrhagic and anti-inflammatory properties. Plant remedies may prove to be an effective alternate for antivenom sera with less adverse events and better tolerability. To the best of our knowledge, this is the first comprehensive review of medicinal plants possessing anti-snake venom activities against certain species of snakes. The current review highlights the investigated plants with their phytochemical analysis to integrate the available information for future research and development of antivenom sera.

Neutralization of toxic activities of Bothrops asper snake venom by ethnomedicinal plants used in Central America, with emphasis in Guatemala: a review / Neutralización de actividades tóxicas del veneno de la serpiente Bothrops asper por plantas etnomedicinales utilizadas en Centroamérica, con énfasis en Guatemala: Revisión

There are few scientific studies that explore the use of medicinal plants for snakebite envenoming in Central America, although plant-based therapies have been traditionally used in the region. This work reviews the studies conducted in Central America to assess the ability of extracts obtained from plants of local ethnomedical use to inhibit toxic activities of the venom of Bothrops asper, the snake responsible for approximately half of the snakebite envenomings in these countries. The search prioritized the description of the plants used in Guatemala, since most of the studies described in this work were conducted in that country, although references to other countries are included. Information concerning secondary metabolites and other pharmacological activities of these plant species, relevant to the treatment of snakebites, was also described. The literature search was conducted in the Google Scholar, PubMed and Scopus databases and completed with locally available literature. It was found that extracts of 12 plant species inhibited the hemorrhagic effect of the venom and three neutralized the edema-forming activity, while inhibition of proteolytic and phospholipase A2 (PLA2) activities was achieved by three and one plant species, respectively. Only Brownea rosa-de-monte was able to effectively counteract the in vitro coagulant effect of the venom. Some plant extracts screened in Guatemala demonstrated procoagulant or anti-thrombin intrinsic effects that might aggravate the coagulopathy induced by the venom. These findings underscore the need of carrying out scientific studies aimed to validate the inhibitory potential of Central American plant extracts and their metabolites against B. asper venom.

Pocos estudios científicos han explorado el uso de plantas medicinales para el tratamiento del envenenamiento ofídico en Centroamérica, a pesar de que las terapias basadas en plantas son de uso tradicional en la región. Este trabajo recopiló información sobre los estudios realizados en Centroamérica para evaluar la capacidad de extractos de plantas de uso etno-médico para inhibir las actividades tóxicas del veneno de Bothrops asper, la serpiente responsable de aproximadamente la mitad de los envenenamientos ofídicos en Centroamérica. La búsqueda priorizó la descripción de plantas utilizadas en Gua-temala, ya que la mayoría de los estudios aquí descritos fueron realizados en ese país. También se incluyó la descripción de los metabolitos secundarios y otras actividades farmacológicas de las especies evaluadas, que podrían explicar su uso como antiofídicos. La búsqueda de literatura se realizó en las bases de datos de Google Scholar, PubMed, Scopus, y se completó con literatura disponible localmente. Se determinó que 12 extractos de plantas inhibieron el efecto hemorrágico del veneno y tres el efecto edematígeno; la actividad proteolítica fue inhibida por extractos de tres especies y la fosfolipasa A2 (PLA2) por una especie. Solamente Brownea rosa-de-monte demostró inhibir efectivamente el efecto coagulante del veneno in vitro. Algunos extractos de las plantas tamizadas en Guatemala demostraron efectos procoagulantes o anti-trombina intrínsecos, que podrían agravar las alteraciones inducidas por el veneno en la coagulación. Estos hallazgos enfatizan la necesidad de validar el potencial de extractos de plantas centroamericanas y sus metabolitos secundarios para neutralizar el veneno de B. asper.

Características clínico - epidemiológicas de los accidentes ofídicos en un hospital de la Amazonía del Perú / Clinico-epidemiologic characteristics of ophidic accidents in a hospital of the amazonia of Peru

Introducción: En el Perú, los accidentes ofídicos son un importante problema de salud pública, debido a una amplia distribución territorial de diferentes tipos de serpientes. Objetivo: Describir las características clínico - epidemiológicas y el manejo de los accidentes ofídicos registrados en un hospital de Perú. Métodos: Estudio de serie de casos, realizado entre enero del 2011 a diciembre 2015 en el Hospital Santa Rosa de Puerto Maldonado. Se revisaron 256 historias clínicas de pacientes con diagnóstico definitivo de ofidismo. Se analizaron variables sociodemográficas, clínicas y evolución de los pacientes. Resultados: El 78,5 por ciento de pacientes fueron varones, el grupo de edad más afectado fueron los adultos. La mayoría de los accidentes ocurrieron en el mes de marzo (12,5 por ciento). Un 39 por ciento de los pacientes se dedicaba al trabajo agrícola. Entre las 16:00 y 19:59 horas se produjeron 35,2 por ciento de los accidentes, 71,1 por ciento reportó como causante del accidente a la serpiente Bothrops atrox. El 71,5 por ciento de las mordeduras se presentaron en miembros inferiores. La mayoría de pacientes recibió tratamiento específico con antibotrópico polivalente (90,6 por ciento). Conclusiones: En la población estudiada, el sexo más afectado es el masculino con una edad entre 27 a 59 años. La serpiente más frecuente causante de los accidentes fue la Bothrops atrox, más conocida entre los pobladores como "jergón". En la mayoría de los casos se administró como tratamiento específico el suero antiofídico(AU)

Introduction: In Peru, ophidian accidents are an important public health problem due to a wide territorial distribution of different types of snakes. Objective: To describe the clinical-epidemiological characteristics and the management of ophidian accidents registered in a hospital in Peru. Methods: Case series study carried out between January 2011 to December 2015 at the Santa Rosa Hospital in Puerto Maldonado, 256 medical records of patients with a definitive diagnosis of ophidism were reviewed. Sociodemographic and clinical variables and the evolution of the patients were analyzed. Results: A total of 78.5 percent of patients were men, the age group most affected were adults. Most of the accidents occurred in March (12.5 percent). 39 percent of the patients were engaged in agricultural work. Between 4:00 p.m. and 7:59 p.m., 35.2 percent of the accidents occurred. 71.1 percent reported the Bothrops atrox snake as the cause of the accident. 71.5 percent of the bites occurred on the lower limbs. Most patients received specific treatment with polyvalent anti-botropic (90.6 percent). Conclusions: In the studied population, the most affected sex is the male with an age between 27 and 59 years. The most frequent snake causing the accidents was the Bothrops atrox, better known among the inhabitants as "jergón". In most cases, antivenom was administered as a specific treatment(AU)

King Cobra and snakebite envenomation: on the natural history, human-snake relationship and medical importance of Ophiophagus hannah

King Cobra (Ophiophagus hannah) has a significant place in many cultures, and is a medically important venomous snake in the world. Envenomation by this snake is highly lethal, manifested mainly by neurotoxicity and local tissue damage. King Cobra may be part of a larger species complex, and is widely distributed across Southeast Asia, southern China, northern and eastern regions as well as the Western Ghats of India, indicating potential geographical variation in venom composition. There is, however, only one species-specific King Cobra antivenom available worldwide that is produced in Thailand, using venom from the snake of Thai origin. Issues relating to the management of King Cobra envenomation (e.g., variation in the composition and toxicity of the venom, limited availability and efficacy of antivenom), and challenges faced in the research of venom (in particular proteomics), are rarely addressed. This article reviews the natural history and sociocultural importance of King Cobra, cases of snakebite envenomation caused by this species, current practice of management (preclinical and clinical), and major toxinological studies of the venom with a focus on venom proteomics, toxicity and neutralization. Unfortunately, epidemiological data of King Cobra bite is scarce, and venom proteomes reported in various studies revealed marked discrepancies in details. Challenges, such as inconsistency in snake venom sampling, varying methodology of proteomic analysis, lack of mechanistic and antivenomic studies, and controversy surrounding antivenom use in treating King Cobra envenomation are herein discussed. Future directions are proposed, including the effort to establish a standard, comprehensive Pan-Asian proteomic database of King Cobra venom, from which the venom variation can be determined. Research should be undertaken to characterize the toxin antigenicity, and to develop an antivenom with improved efficacy and wider geographical utility. The endeavors are aligned with the WHO´s roadmap that aims to reduce the disease burden of snakebite by 50% before 2030.(AU)

A case report of human intoxication due to a snakebite by the opisthoglyphous dipsadid Thamnodynastes lanei Bailey, Thomas & Silva-Jr, 2005

Abstract We present a case of human intoxication due to a snakebite by the opisthoglyphous dipsadid Thamnodynastes lanei. A 26-year-old man was bitten on the right hand and was not medicated. Bleeding lasted a few seconds, while paresthesia, chills, and headache persisted for up to 10 hours. The pain disappeared after a week, and the edema, itching, and prickling persisted for another 3 days. Although this patient's symptoms were typical of bites by South American opisthoglyphous snakes, they persisted longer than those of bites by some congeneric species. Our report adds a species to the list of medically relevant snakes.

Design, synthesis, and evaluation of Bothrops venom serine protease peptidic inhibitors

In Central and South America, snakebite envenomation is mainly caused by Bothrops spp. snakes, whose venoms feature significant biochemical richness, including serine proteases. The available bothropic antivenoms are efficient in avoiding fatalities, but do not completely neutralize venom serine proteases, which are co-responsible for some disorders observed during envenomation. Methods: In order to search for tools to improve the antivenom's, 6-mer peptides were designed based on a specific substrate for Bothrops jararaca venom serine proteases, and then synthesized, with the intention to selectively inhibit these enzymes. Results: Using batroxobin as a snake venom serine protease model, two structurally similar inhibitor peptides were identified. When tested on B. jararaca venom, one of the new inhibitors displayed a good potential to inhibit the activity of the venom serine proteases. These inhibitors do not affect human serine proteases as human factor Xa and thrombin, due to their selectivity. Conclusion: Our study identified two small peptides able to inhibit bothropic serine proteases, but not human ones, can be used as tools to enhance knowledge of the venom composition and function. Moreover, one promising peptide (pepC) was identified that can be explored in the search for improving Bothrops spp. envenomation treatment.(AU)

Proteomics, toxicity and antivenom neutralization of Sri Lankan and Indian Russell's viper (Daboia russelii) venoms

The western Russell's viper (Daboia russelii) is widely distributed in South Asia, and geographical venom variation is anticipated among distant populations. Antivenoms used for Russell's viper envenomation are, however, raised typically against snakes from Southern India. The present study investigated and compared the venom proteomes of D. russelii from Sri Lanka (DrSL) and India (DrI), the immunorecognition of Indian VINS Polyvalent Antivenom (VPAV) and its efficacy in neutralizing the venom toxicity. Methods: The venoms of DrSL and DrI were decomplexed with C18 high-performance liquid chromatography and SDS-polyacrylamide gel electrophoresis under reducing conditions. The proteins fractionated were identified through nano-ESI-liquid chromatography-tandem mass spectrometry (LCMS/MS). The immunological studies were conducted with enzyme-linked immunosorbent assay. The neutralization of the venom procoagulant effect was evaluated in citrated human plasma. The neutralization of the venom lethality was assessed in vivo in mice adopting the WHO protocol. Results: DrSL and DrI venom proteomes showed comparable major protein families, with phospholipases A2 (PLA2) being the most abundant (> 60% of total venom proteins) and diverse (six protein forms identified). Both venoms were highly procoagulant and lethal (intravenous median lethal dose in mice, LD50 = 0.24 and 0.32 µg/g, for DrSL and DrI, respectively), while lacking hemorrhagic and anticoagulant activities. VPAV was immunoreactive toward DrSL and DrI venoms, indicating conserved protein antigenicity in the venoms. The high molecular weight venom proteins were, however, more effectively immunorecognized than small ones. VPAV was able to neutralize the coagulopathic and lethal effects of the venoms moderately. Conclusion: Considering that a large amount of venom can be injected by Russell's viper during envenomation, the potency of antivenom can be further improved for optimal neutralization and effective treatment. Region-specific venoms and key toxins may be incorporated into the immunization procedure during antivenom production.(AU)

Toxicological, enzymatic, and immunochemical characterization of Bothrops asper (Serpentes: Viperidae) reference venom from Panama / Caracterización toxicológica, enzimática e inmunoquímica del veneno de referencia de Bothrops asper (Serpentes: Viperidae) de Panamá

Introduction: It is estimated that 2 000 snakebites occur in Panama every year, 70 % of which are inflicted by Bothrops asper. Objective: To determine the biochemical and toxicologic effects and to assess the immunochemical characteristics of a reference pool of B. asper venom representative of Panama. Methods: The reference venom was prepared as a homogeneous mixture of the venoms obtained from 78 adult snakes collected in four geographic areas of Panama. Enzymatic and toxicological activities were assessed. The electrophoretic pattern was studied by SDS-PAGE. Immunoreactivity of various antivenoms was analyzed by Western blot. Results: B. asper reference venom has lethal, hemorrhagic, myotoxic, edema-forming, coagulant, defibrinating, proteinase and phospholipase A2 activities. SDS-PAGE showed the presence of protein bands with molecular weights ranging from 8 to 70 kDa, with the presence of predominant bands at ≈ 15 kDa and ≈ 30 to 66 kDa, which likely correspond to phospholipases A2 and metalloproteinases, respectively. Immunoblotting showed a high degree of recognition by various antivenoms, especially by antivenoms from Colombia and Costa Rica. Conclusions: Following recommendations by the World Health Organization, this reference venom of B. asper of Panama will become a useful tool for the preclinical evaluation of antivenoms distributed in this country.

Introducción: Se estima que 2 000 mordeduras de serpiente ocurren en Panamá cada año, el 70 % de las cuales son infligidas por Bothrops asper. Objetivo: Determinar los efectos bioquímicos y toxicológicos y evaluar las características inmunoquímicas del veneno de referencia de B. asper representativo de Panamá. Métodos: El veneno de referencia se preparó como una mezcla homogénea de los venenos obtenidos de 78 serpientes adultas recolectadas en cuatro áreas geográficas de Panamá. Se evaluaron las actividades enzimáticas y toxicológicas. El patrón electroforético se estudió mediante SDS-PAGE. La inmunoreactividad de varios antivenenos se analizó mediante transferencia de Western. Resultados: El veneno de referencia de B. asper tiene actividades letales, hemorrágicas, miotóxicas, formadoras de edema, coagulantes, desfibrinante, proteolítica y de fosfolipasa A2. El análisis de SDS-PAGE mostró la presencia de bandas de proteínas con pesos moleculares que varían de 8 a 70 kDa, con la presencia de bandas predominantes a ≈ 15 kDa y ≈ 30 a 66 kDa, que probablemente corresponden a fosfolipasas A2 y metaloproteinasas, respectivamente. La inmunotransferencia mostró un alto grado de reconocimiento por varios antivenenos, especialmente por antivenenos de Colombia y de Costa Rica. Conclusiones: Siguiendo las recomendaciones de la Organización Mundial de la Salud, este veneno de referencia de B. asper de Panamá se convertirá en una herramienta útil para la evaluación preclínica de antivenenos distribuidos en este país.

Inhibición de las actividades proteolítica y fosfolipasa A2 del veneno de Bothrops asper por el extracto etanólico de Neurolaena lobata (L) Cass / Inhibition of proteolytic and phospholipase A2 activities of Bothrops asper venom by the ethanolic extract of Neurolaena lobata (L) Cass

Neurolaena lobata es utilizada tradicionalmente en Centroamérica para tratar la mordedura de serpiente, pero su efectividad para contrarrestar el envenenamiento producido por Bothrops asper ha sido poco estudiada. Se evaluó la capacidad del extracto etanólico de sus hojas para inhibir las actividades proteolítica, fosfolipasa A2 (PLA2; evaluada como hemólisis indirecta) y coagulante del veneno in vitro. El material vegetal fue colectado en Izabal, Guatemala, secado, se hicieron extracciones con etanol y se evaluó la presencia de actividades proteolítica, PLA2 y coagulante in-trínsecas en ensayos de concentración-actividad. Los efectos inhibitorios de la actividad proteolítica y PLA2 del veneno se evaluaron después de pre-incubar concentraciones variables del extracto con concentraciones fijas de veneno. La inhibición de la actividad coagulante del veneno no fue evaluada porque el extracto presentó actividad anticoagulante intrínseca dependiente de la concentración. El extracto inhibió completamente las actividades proteolítica (CE50 = 15.7 µg/µl) y PLA2 (CE50 = 32.5 µg/µl) del veneno. El análisis fitoquímico utilizando ensayos macro y semimicrométricos de cromatografía en capa fina, demostró la presencia de flavonoides, cumarinas, saponinas, taninos, sesquiterpenlactonas y aceites esenciales en el extracto. Su efecto sobre las proteínas del veneno se evaluó por electroforesis SDS-PAGE, mostrando cambios en el patrón electroforético atribuidos a la formación de complejos moleculares con los metabo-litos del extracto. Los resultados indican que el extracto podría inhibir los efectos tóxicos del veneno inducidos por las metaloproteinasas dependientes de zinc (SVMPs) y PLA2s, pero podría afectar las alteraciones en la coagulación, coadyuvando en la desfibrinogenación inducida por el veneno.

Neurolaena lobata has been used by traditional healers in Central America to treat snakebite, but its ability to neutralize Bothrops asper envenomations needs to be proved. This study evaluated the inhibitory potential of the ethanolic extract of the leaves of N. lobata against proteolytic, phospholipase A2 (PLA2) and coagulant activities of the venom in vitro. Leaves were collected in Izabal, Guatemala, dried, extracted with ethanol and concentration-response assays were conducted to detect intrinsic proteolytic, PLA2 (evaluated as indirect hemolysis) and coagulant activities. Assays for anti-proteolytic and anti-PLA2 activities were performed after pre-incubation of several amounts of extract with a fixed concentration of venom. Inhibition assay for the coagulant effect of the venom was not tested because pre-incubation of thrombin with the extract prolonged the clotting time of plasma in a concentration-dependent manner. Proteolytic (EC50 = 15.7 µg/µl) and PLA2 (EC50 = 32.5 µg/µl) activities of the venom resulted completely inhibited by the extract. Phytochemical profiles, determined by micrometric assays and semi microanalysis by thin layer chro-matography, showed the presence of flavonoids, coumarins, saponins, tannins, sesquiterpene lactones and essential oils in the extract. SDS-PAGE was used to assess the action of the extract on the venom proteins. Results showed changes in the electrophoretic profile, probably due to the formation of insoluble complexes with plant specialized metabolites. These findings demonstrated that the extract could be able to inhibit toxic effects triggered by zinc-dependent snake venom metalloproteinases (SVMPs) y PLA2s but might aggravate the alterations induced by the venom in coagulation.

Severe tissue complications in patients of Bothrops snakebite at a tertiary health unit in the Brazilian Amazon: clinical characteristics and associated factors

Abstract INTRODUCTION: Snakebites in the Brazilian Amazon are caused mostly by snakes from the Bothrops genus and envenomated patients may suffer from tissue complications. METHODS: This study aimed to identify risk factors for severe tissue complications (STC) in patients with Bothrops snakebite in the Amazonas state, Brazil. RESULTS: Snakebites that were classified as severe and affected female patients with comorbidities presented greater risks of developing STCs. In addition, hospitalizations of patients with STC exceeded 5 days. CONCLUSIONS: Clinical and epidemiological characteristics can prove essential for assessing the evolution of STC and clinical prognosis of patients with Bothrops snakebites.

Envenenamiento ofídico en Costa Rica: logros y tareas pendientes / Snakebite envenoming in Costa Rica: achievements and pending tasks

Resumen Objetivo: Efectuar un análisis de los logros en Costa Rica en cuanto al problema de los envenenamientos por mordeduras de serpientes, y señalar tareas pendientes para reducir aún más el impacto de esta patología. Metodología: Se efectuó una revisión de bibliografía relacionada con el estudio del envenenamiento ofídico en Costa Rica y con los avances efectuados en el tema, en el país. Paralelamente, se identificaron aspectos que requieren atención en el manejo de esta enfermedad tropical desatendida. Conclusiones: Desde las primeras décadas del siglo XX, se han realizado avances significativos en la comprensión y manejo del problema de los envenenamientos por mordedura de serpiente en Costa Rica. Se ha trabajado desde una visión integral que incluye: investigación científico-tecnológica, producción y distribución de antivenenos, esfuerzos en prevención, capacitación de las personas profesionales de la salud en el diagnóstico y tratamiento, y docencia de grado y posgrado en el tema. El país ha asumido un papel de liderazgo a nivel internacional, tanto en el plano académico como en la provisión de antivenenos a muchos países. No obstante, aún quedan aspectos del problema que requieren nuevos esfuerzos en nuestro medio, sobre todo en lo referente a la atención de las consecuencias biomédicas, psicológicas, sociales y económicas que sufren las personas afectadas.

Abstract Aim: To analyze the achievements made in Costa Rica in confronting the problem of snakebite envenomings, and to identify pending tasks to further reduce the impact of this pathology. Methods: A review of the literature on snakebite envenomings in Costa Rica was carried out, identifying the main achievements reached in the country. In parallel, issues that require renewed attention in the management of this neglected tropical disease were identified. Conclusions: Since the first decades of the 20th century, significant advances have been made in Costa Rica for understanding and confronting the problem of snakebite envenomings. An integrative perspective has been implemented, which includes scientific and technological research, production and distribution of antivenoms, prevention campaigns, training of health professionals in the diagnosis and treatment of envenomings, and teaching at graduate and undergraduate levels. Costa Rica has had a leading international role in this topic at the academic level, and by providing antivenoms to many countries. Nevertheless, there are issues that require further efforts, especially regarding the attention to the biomedical, psychological, social and economic consequences suffered by people affected by snakebites.

Neutralización de la actividad letal del veneno de serpiente Bothrops atrox por suero hiperinmune de llama (Lama glama) / Neutralization of the lethal activity from Bothrops atrox venom by hyperimune llama serum (Lama glama)

RESUMEN Objetivos: Evaluar la capacidad del suero hiperinmune de llama (Lama glama) para neutralizar la letalidad del veneno de la serpiente Bothrops atrox en ratones de laboratorio. Materiales y métodos: Se calculó la dosis letal media (DL50) de un pool de venenos de serpientes de Bothrops atrox de Perú, y se midieron los títulos de anticuerpos por ensayo ELISA; así como la potencia de neutralización del suero inmune por el cálculo de la dosis efectiva media (DE50) durante el periodo de inmunización. Resultados: La DL50 del veneno fue de 3,96 µg/g, similar a otros trabajos realizados en Bothrops atrox en Perú. Los títulos de anticuerpos contra el veneno se incrementan rápidamente en la llama mostrando una rápida respuesta inmune; sin embargo, la capacidad de neutralización se incrementa más lentamente y requiere de varias dosis y refuerzos de las inmunizaciones alcanzado una DE50 de 3,30 µL/g ratón y una potencia de neutralización 3,6 mg/mL después de 15 inmunizaciones. Conclusiones: El suero hiperinmune de llama es capaz de neutralizar la letalidad del veneno de la serpiente Bothrops atrox de Perú en ratones de laboratorio.

ABSTRACT Objectives: To evaluate the capacity of the hyperimmune llama serum (Lama glama) to neutralize the lethal activity of Bothrops atrox venom in laboratory mice. Materials and methods: Mean lethal dose (LD50) was calculated from a Bothrops atrox venom sample pool from Peru. The antibody titers were measured by ELISA assay; and the immune serum neutralization potency was measured by calculating the mean effective dose (ED50) during the immunization period. Results: The venom's LD50 was 3.96 μg/g; similar to what was found in other studies about Bothrops atrox carried out in Peru. The titers of antibodies against the venom increased rapidly in the llama, demonstrating a fast immune response; however, the neutralization capacity increased slowly and required several doses and immunization reinforcements, obtaining a ED50 of 3.30 μL/g mouse and a neutralization potency of 3.6 mg/mL after 15 immunizations. Conclusions: The hyperimmune llama serum is able to neutralize the lethality of the Bothrops atrox venom from Peru in laboratory mice.

Avaliação do uso de soros antivenenos na emergência de um hospital público regional de Vitória da Conquista (BA), Brasil / Evaluation of the use of antivenom sera in the emergency service of a regional public hospital in Vitória da Conquista (BA), Brazil

Resumo O presente estudo tem como objetivo caracterizar o perfil epidemiológico de vítimas de acidentes escorpiônicos e ofídicos e avaliar a adequação das prescrições de soros antivenenos. Estudo transversal cujas fontes de dados foram as fichas de notificação de acidentes por animais peçonhentos do Sistema de Informação de Agravos de Notificação no município de Vitória da Conquista (BA), Brasil. Foram incluídas as informações de acidentes escorpiônicos ou ofídicos no período entre julho de 2016 e junho de 2017 atendidos no município. Os dados obtidos e as variáveis de interesse foram analisadas de acordo com as perguntas deste estudo. No período observado foram atendidas 293 vítimas de acidentes por animais peçonhentos. Destas, 149 (50,9%) foram homens e 114 (38,9%) possuíam entre 20 a 59 anos. Foram 235 (80,9%) casos de escorpionismo e 58 (19,1%) de ofidismo. Destes, 203 (69,3%) foram classificados como leves e em 200 (68,5%) casos foi prescrita soroterapia para estes pacientes. Quanto à adequação das prescrições, 172 (59,7%) foram julgadas inadequadas e destas, o uso de número de ampolas acima do indicado foi a mais frequente. A prescrição inapropriada de soros antivenenos ocorreu em aproximadamente em 60% dos casos avaliados. Apesar disso, a maioria dos acidentes foi classificada como leve, em homens jovens.

Abstract This study aims to characterize the epidemiological profile of victims of scorpion and snakebite envenomations and to evaluate the adequacy of antivenom sera prescriptions. This is a cross-sectional study whose data sources were the envenomation notification information sheets of the Notifiable Diseases Information System in the city of Vitória da Conquista (BA), Brazil. We included information on scorpion or snakebite envenomations attended in the municipality in the period between July 2016 and June 2017. The data obtained and the variables of interest were analyzed according to the questions of this study. In the observed period, 293 victims of envenomations were treated. Of these, 149 (50.9%) were men, and 114 (38.9%) were 20-59 years old. In total, 235 (80.9%) cases of scorpionism and 58 (19.1%) of ophidism were reported. Of these, 203 (69.3%) were classified as mild, and in 200 (68.5%) cases, serum therapy was prescribed for the patients. Regarding the adequacy of the prescriptions, 172 (59.7%) were considered inadequate, and of these, the use of some vials above than indicated was the most frequent. The inappropriate prescription of antivenom sera occurred in approximately 60% of the evaluated cases. Despite this, most accidents were classified as mild - in young men.

Informe especial: Envenenamiento por animal ponzoñoso: Alacranismo / Special report: Poisonous by venomous animal: Scorpions

Presentación de un caso, notificado el 9 de enero de 2017, a la Gerencia Operativa de Epidemiología del Gobierno de la Ciudad de Buenos Aires por un efector privado de la Ciudad, de envenenamiento por animal ponzoñoso (Alacranismo) en un paciente residente en la Ciudad de Buenos Aires. Se describen el cuadro clínico y el tratamiento recibido, la evolución del caso, la importancia de distintas acciones de vigilancia epidemiológica, el procedimiento de notificación, medidas de protección, y medidas de prevención y control de accidentes. Incluye datos de centros públicos nacionales y de la Ciudad de Buenos Aires especializados en asistencia y/o in-formación sobre animales venenosos

Venomics and antivenomics of the poorly studied Brazil's lancehead, Bothrops brazili (Hoge, 1954), from the Brazilian State of Pará

The Brazil's lancehead, Bothrops brazili, is a poorly studied pit viper distributed in lowlands of the equatorial rainforests of southern Colombia, northeastern Peru, eastern Ecuador, southern and southeastern Venezuela, Guyana, Suriname, French Guiana, Brazil, and northern Bolivia. Few studies have been reported on toxins isolated from venom of Ecuadorian and Brazilian B. brazili. The aim of the present study was to elucidate the qualitative and quantitative protein composition of B. brazili venom from Pará (Brazil), and to carry out a comparative antivenomics assessment of the immunoreactivity of the Brazilian antibothropic pentavalent antivenom [soro antibotrópico (SAB) in Portuguese] against the venoms of B. brazili and reference species, B. jararaca. Methods: We have applied a quantitative snake venomics approach, including reverse-phase and two-dimensional electrophoretic decomplexation of the venom toxin arsenal, LC-ESI-MS mass profiling and peptide-centric MS/MS proteomic analysis, to unveil the overall protein composition of B. brazili venom from Pará (Brazil). Using third-generation antivenomics, the specific and paraspecific immunoreactivity of the Brazilian SAB against homologous (B. jararaca) and heterologous (B. brazili) venoms was investigated. Results: The venom proteome of the Brazil's lancehead (Pará) is predominantly composed of two major and three minor acidic (19%) and two major and five minor basic (14%) phospholipase A2 molecules; 7-11 snake venom metalloproteinases of classes PI (21%) and PIII (6%); 10-12 serine proteinases (14%), and 1-2 L-amino acid oxidases (6%). Other toxins, including two cysteine-rich secretory proteins, one C-type lectin-like molecule, one nerve growth factor, one 5'-nucleotidase, one phosphodiesterase, one phospholipase B, and one glutaminyl cyclase molecule, represent together less than 2.7% of the venom proteome. Third generation antivenomics profile of the Brazilian pentabothropic antivenom showed paraspecific immunoreactivity against all the toxin classes of B. brazili venom, with maximal binding capacity of 132.2 mg venom/g antivenom. This figure indicates that 19% of antivenom's F(ab')2 antibodies bind B. brazili venom toxins. Conclusion: The proteomics outcome contribute to a deeper insight into the spectrum of toxins present in the venom of the Brazil's lancehead, and rationalize the pathophysiology underlying this snake bite envenomings. The comparative qualitative and quantitative immunorecognition profile of the Brazilian pentabothropic antivenom toward the venom toxins of B. brazili and B. jararaca (the reference venom for assessing the bothropic antivenom's potency in Brazil), provides clues about the proper use of the Brazilian antibothropic polyvalent antivenom in the treatment of bites by the Brazil's lancehead.(AU)

Envenomation by Trimeresurus stejnegeri stejnegeri: clinical manifestations, treatment and associated factors for wound necrosis

Trimeresurus stejnegeri stejnegeri bite induces tissue swelling, pain, thrombocytopenia, rhabdomyolysis, and acute renal failure. However, the incidence of coagulopathy, factors associated with wound necrosis, and the appropriate management of this condition have not been well characterized yet. Materials: This study included patients bitten by T. s. stejnegeri that were admitted to the study hospitals from 2001 to 2016. Patient characteristics, laboratory data, and management approaches were compared in victims with and without wound necrosis. Results: A total of 185 patients were evaluated: three patients (1.6%) were asymptomatic; whereas tissue swelling and pain, local ecchymosis, wound necrosis, coagulopathy, thrombocytopenia, rhabdomyolysis, and renal impairment were present in 182, 53, 13, 15, 10, 1, and 3 patients, respectively. One patient died from coagulopathy and hemorrhagic shock. Antivenom was administered to all envenomed patients at a median time of 1.8 h after the bite. The median total dose of antivenom was five vials. Chi-square analysis showed that bitten fingers, using cold packs during first aid, presence of bullae or blisters, lymphangitis or lymphadenitis, local numbness and suspected infection to be significantly associated with wound necrosis. After adjustment using a multivariate logistic regression model, only cold packs as first aid, bulla or blister formation, and wound infection remained significant. Conclusions: The main effects of T. s. stejnegeri envenomation are tissue swelling, pain, and local ecchymosis. We do not recommend the use of cold packs during first aid to reduce wound pain, as this may be a risk factor for wound necrosis. In addition, patients with bulla or blister formation should be carefully examined for subsequent wound necrosis. Antiplatelet use may worsen systemic bleeding. No severe rhabdomyolysis or renal failure was observed in this large case series, we therefore considered that they were not prominent effects of T. s. stejnegeri bite.(AU)

Chicken antibodies against venom proteins of Trimeresurus stejnegeri in Taiwan

The venom of bamboo vipers (Trimeresurus stejnegeri - TS), commonly found in Taiwan, contains deadly hemotoxins that cause severe envenomation. Equine-derived antivenom is a specific treatment against snakebites, but its production costs are high and there are some inevitable side effects. The aim of the present work is to help in the development of an affordable and more endurable therapeutic strategy for snakebites. Methods: T. stejnegeri venom proteins were inactivated by glutaraldehyde in order to immunize hens for polyclonal immunoglobulin (IgY) antibodies production. After IgY binding assays, two antibody libraries were constructed expressing single-chain variable fragment (scFv) antibodies joined by the short or long linker for use in phage display antibody technology. Four rounds of biopanning were carried out. The selected scFv antibodies were then further tested for their binding activities and neutralization assays to TS proteins. Results: Purified IgY from egg yolk showed the specific binding ability to TS proteins. The dimensions of these two libraries contain 2.4 × 107 and 6.8 × 107 antibody clones, respectively. An increase in the titers of eluted phage indicated anti-TS clones remarkably enriched after 2nd panning. The analysis based on the nucleotide sequences of selected scFv clones indicated that seven groups of short linkers and four groups of long linkers were identified. The recombinant scFvs showed significant reactivity to TS venom proteins and a cross-reaction to Trimeresurus mucrosquamatus venom proteins. In in vivo studies, the data demonstrated that anti-TS IgY provided 100% protective effects while combined scFvs augmented partial survival time of mice injected with a lethal amount of TS proteins. Conclusion: Chickens were excellent hosts for the production of neutralization antibodies at low cost. Phage display technology is available for generation of monoclonal antibodies against snake venom proteins. These antibodies could be applied in the development of diagnostic kits or as an alternative for snakebite envenomation treatment in the near future.(AU)