ArticleLiterature Review

Coral snake bites in Brazilian Amazonia: Perpetrating species, epidemiology and clinical aspects

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Abstract

Coral snakes constitute a relatively diverse and little known group of venomous snakes. So far, data for this kind of snakebite in the Amazon region are based only on case reports. This study takes advantage of novel data from the Brazilian Health Ministry database from 2010 to 2015 and presents a review of the cases reported in the literature regarding the Amazonian biome both from Brazil and nearby countries. Thirty-four cases reported in the database were used in the study, representing 0.05% of the snakebites in Brazilian Amazonia for that period. The incidence rate was 0.123 cases/100,000 inhabitants/year. The most affected group is that of working age men, suggesting occupational risk. Most of bites were on lower limbs. Pain, edema and paresthesia were the most common symptoms. Systemic symptoms not usually associated with coral snakes envenomings, such as coagulopathy and thrombocytopenia, have been reported in Amazonia. Five patients received less antivenom than indicated by the Health Ministry. Based on these results, we recommend the execution of educational programs to avoid such accidents and to teach both the general public and health professionals the correct treatment for the bites. We also suggest that the covering of Intensive Care Units in the region needs to be improved to avoid deaths.

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... Factors associated with increased snakebite prevalence include field labor, male gender, middle age, lower education status, low income, and residence in rural areas. 66,[68][69][70][71][72][73][74][75][76][77] Associated environmental factors include monsoon season and evening hours. 71,73,78,79 In the United States, increased biting rates have been reported in the locations of Texas, Florida, West Virginia, Oklahoma, and Louisiana. ...
... 80 Symptoms largely include pain and swelling with accompanying erythema, ecchymosis, and paresthesia. Additional symptoms are described in Table 4. 68,75,81 Antivenom such as CroFab, which has been recognized as the first line over antivenin crotalidae polyadvent, is successful in the treatment of most bites. 75,82,83 Additional protocol features should include removal of articles that may constrict limb swelling, maintenance of patent airway, and immobilization of bitten limb at a level below the heart to prevent systemic spread. ...
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Animal bites are common worldwide. Due to the plethora of animals, there are diverse pathogens with specific associated risks and treatment algorithms. It is crucial to understand these to develop and execute appropriate management plans. This practical review was designed to amalgamate the most common bites worldwide and synthesize data to help guide treatment plans. Methods: A PubMed literature search was performed focusing on the major animal bites. High-level studies were preferred and analyzed but lower-level studies were also used if high-level studies did not exist. Results: The tables presented in this article cover the pertinent information regarding the incidence, common presentation, initial treatment, and potential complications associated with bites from dogs, cats, horses, rodents, snakes, marine life, and spiders. Many of the pathogens associated with the bites are treatable with various and somewhat common antimicrobials, though some are less easy to access. Basic irrigation, debridement, and wound culture are common to almost every animal and should be the first step in treatment. Conclusions: Based on the current studies, the most important factor in treating animal bites is timely presentation to a medical facility and/or physician. It is critical that the offending animal be accurately identified to help guide medical and surgical algorithms, including specific antimicrobial treatment guided by the most commonly presenting pathogens specific to certain animals.
... Bites of the genus Micrurus-often referred to as coral snakescan be quite dangerous but are a small proportion of the reported snake bites within their range (Greene, 2020). Mortality from these bites is usually due to neurotoxicity which can compromise the respiratory system and lead to asphyxiation (Bucaretchi et al., 2016;Canãs et al., 2017;Anwar and Bernstein, 2018;Bisneto et al., 2020). The primary neurotoxins are from the three-finger toxin (3FTx) and PLA 2 toxin families, the relative prevalence of which in the venom varies according to species and geography (Sanz et al., 2019). ...
... We find it unlikely that the age of this particular batch of antivenom rendered it ineffective since it did produce an effect on M. ibiboboca and because this antivenom and others have been shown to retain their effectiveness long past the original expiry date if stored properly (O'Leary et al., 2009;Wood et al., 2013;Lister et al., 2017). While the major clinical concern during severe Micrurus bites primarily stems from their neurotoxins (Greene, 2020;Bucaretchi et al., 2016;Canãs et al., 2017;Anwar and Bernstein, 2018;Bisneto et al., 2020), there are certainly reports of patients who display coagulopathies as additional complications and our results suggest these could be particularly severe in cases of envenomation by M. laticollaris (Cecchini et al., 2005;Oliveira et al., 2017;Rey-Suárez et al., 2017). This research suggests that, in such cases, Coralmyn is unlikely to alleviate those symptoms and they may have to be treated using other therapeutics such as varespladib. ...
Article
Snakebite is a neglected tropical disease with a massive global burden of injury and death. The best current treatments, antivenoms, are plagued by a number of logistical issues that limit supply and access in remote or poor regions. We explore the anticoagulant properties of venoms from the genus Micrurus (coral snakes), which have been largely unstudied, as well as the effectiveness of antivenom and a small-molecule phospholipase inhibitor—varespladib—at counteracting these effects. Our in vitro results suggest that these venoms likely interfere with the formation or function of the prothrombinase complex. We find that the anticoagulant potency varies widely across the genus and is especially pronounced in M. laticollaris. This variation does not appear to correspond to previously described patterns regarding the relative expression of the three-finger toxin and phospholipase A2 (PLA2) toxin families within the venoms of this genus. The coral snake antivenom Coralmyn, is largely unable to ameliorate these effects except for M. ibiboboca. Varespladib on the other hand completely abolished the anticoagulant activity of every venom. This is consistent with the growing body of results showing that varespladib may be an effective treatment for a wide range of toxicity caused by PLA2 toxins from many different snake species. Varespladib is a particularly attractive candidate to help alleviate the burden of snakebite because it is an approved drug that possesses several logistical advantages over antivenom including temperature stability and oral availability.
... These bio-ecological characteristics of the two corals explain why the residents reported that they encountered these snakes in aquatic environments and also because they are the species of the genus known to be found in the floodplain forests. The low frequency of accidents with corals reported by residents in this study and also recorded in the Alto Juruá region (Mota-da- Silva et al., 2019d corresponds to the pattern observed for the Amazon (Bisneto et al., 2020) and is probably related to the fact that these snakes are not aggressive, have small fangs, a mouth with a narrow opening and the small amount of venom which they produce and inoculate in the victim (Gutiérrez et al., 2016). ...
... In Brazil, there are approximately 34 species distributed around the country including Micrurus lemniscatus, with three recognized subspecies: M. l. carvalhoi is distributed along the Brazilian east coast from the northeast to southeast and central west of the country, M. l. helleri occurs in the western Brazilian Amazon and M. l. lemniscatus found in the central Brazilian Amazon and northern Brazil (Costa and Bérnils, 2018;Floriano et al., 2019;Nogueira et al., 2019;Silva Jr. et al., 2016). Despite this large distribution, human envenomation by coralsnakes correspond to ~1% of the snakebites registered in Brazil and only a few species are involved in these reports (Bisneto et al., 2020;Bucaretchi et al., 2016a,b;Melgarejo et al., 2016;Risk et al., 2016;Rodrigo et al., 2016;Silva et al., 2018;Souza et al., 2016;Strauch et al., 2018) with Micrurus lemniscatus being the third most frequent species involved (Bucaretchi et al., 2016b). ...
Article
Envenomation by coralsnakes (Micrurus spp.) is characterized by blockade of peripheral neurotransmission mediated by the presence of α- and β-neurotoxins. However, little is known about their cardiovascular activity. Micrurus lemniscatus lemniscatus is a coralsnake found in the Amazon basin and occasionally causes envenomation in humans. In this study, we examined the hemodynamic, vascular and atrial responses to M. l. lemniscatus venom. Anesthetized rats were used for hemodynamic and electrocardiogram (ECG) recordings; in vitro experiments were carried out in rat isolated thoracic aorta and atria preparations. In vivo, venom (0.1 and 0.3 mg/kg) caused immediate and persistent hypotension that was maximal within the first minute with both doses being lethal after ~40 and ~20 min, respectively. ECG, heart and respiratory rates were not altered during the transient hypotension phase induced by venom but all altered prior to death. There was no evidence of myonecrosis in cardiac muscle tissue, pulmonary hemorrhage nor thrombosis in anesthetized rats exposed to venom. In vitro, venom (10 μg/ml) did not contract aortic strips nor affected the maximal responses to pre-contraction with phenylephrine (PE, 0.0001–30 μM) in strips with and without endothelium. However, venom (10 μg/ml) relaxed aortic strips with endothelium pre-contracted with PE. In aortic strips pre-contracted with PE, venom prevented acetylcholine (0.0001–30 μM)-induced relaxation in strips with endothelium without affecting relaxation induced by sodium nitroprusside (0.1–100 nM) in strips without endothelium. Venom (30 μg/ml) produced a transient increase of atrial contractile force without affecting atrial rate. Taken together these findings indicate a predominantly vascular action of the venom, most likely involving toxins interacting with muscarinic receptors.
... Due to its size and biodiversity, the Amazon region harbors many species of venomous snakes of the Viperidae and Elapidae families [6]. The vast majority of snakebites are inflicted by viperid species, and only less than 1% of cases correspond to bites by elapids, i.e., coral snakes of the genus Micrurus [7]. Viperid species in Amazon are classified in the genera Bothrops, Bothrocophias, Crotalus, and Lachesis. ...
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We report here the first known envenomation by Micrurus psyches, the so-called Carib coral snake, which occurred on April 2016 in the surroundings of Saint- Laurent-du-Maroni, Western French Guiana. Besides local neurological symptoms, it featured unexpected electrocardiogram changes, which were emergence of a first-degree atrioventricular block and biphasic T waves, both transient. NewWorld elapid venoms were not known for being cardiotoxic so far. The possible reasons of this cardiac injury are discussed.
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INTRODUCTION: The coral snake Micrurus surinamensis, which is widely distributed throughout Amazonia, has a neurotoxic venom. It is important to characterize the biological and molecular properties of this venom in order to develop effective antitoxins. METHODS: Toxins from the venom of M. surinamensis were analyzed by two-dimensional polyacrylamide gel electrophoresis and their neurotoxic effects in vivo were evaluated. RESULTS AND CONCLUSIONS: Most proteins in the venom had masses < 14kDa, low phospholipase A2 activity, and no proteolytic activity. The toxins inhibited the coagulation cascade. The venom had neurotoxic effects in mice, with a median lethal dose upon intravenous administration of 700 µg/kg. Immunogenic studies revealed abundant cross-reactivity of antielapidic serum with 14kDa toxins and limited cross-reactivity with toxins < 10kDa. These results indicate that antielapidic serum against M. surinamensis venom has weak potency (0.35mg/ml) in mice.
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Background: 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. Keywords: Red-tailed coral snake, Micrurus mipartitus, snake envenomation, Colombia
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Objetivo : determinar el comportamiento epidemiologico del accidente ofidico en el Departamento del Magdalena, segun los eventos notificados durante los anos 2009-2013. Materiales y metodos : estudio de tipo descriptivo y retrospectivo. El tamano muestral fueron 485 casos notificados al Sistema de Vigilancia en Salud Publica. La informacion fue organizada en Microsoft Excel® y procesada en Epi-info® version 3.5.4 de 2012. Se realizo analisis bivariado mediante estadistica descriptiva, prueba de asociacion (or) y significancia (p<0,05); guardando el rigor etico y metodologico correspondiente. Resultados : el grupo etario mas afectado fue el de 10 a 29 anos (44,5 %), con predominio en el sexo masculino (73 %), la mayoria residentes en area rural (59 %). Los municipios con mayor incidencia y notificacion de casos fueron zona bananera (15,9 %), Cienaga (11,8 %), El Banco (10,7 %), Pivijay (9,5 %) y Ariguani (8,2 %). Se encontro asociacion estadistica entre el ser mordido por serpiente mapana y estar realizando tanto labores de agricultura [or= 0,53 (IC95 %: 0,36-0,77; p=0,00116)] como oficios domesticos [or= 2,29 (IC95 %: 1,36 - 3,87; p=0,00148)]. De igual forma, entre el ser mordido por serpiente mapana y presentar nauseas [or= 1,60 (IC95 %: 1,04-2,44; p=0,029)], como manifestacion clinica sistemica. Conclusiones : el accidente ofidico sigue siendo un evento de interes para la salud publica global. Sin embargo, es necesario que exista mayor adherencia al protocolo nacional de vigilancia epidemiologica y se mejore la notificacion por parte de las instituciones primarias para evitar subregistros. Ademas, que se sigan realizando investigaciones entre regiones, que permitan comparar hallazgos y establecer estrategias de control y prevencion.
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Historical clinical case that presented back in 1968 at a time when respiratory support and intensive care techniques were just emerging, with many shortcomings in hospital care areas and monitoring devices. The case is of a 58 year-old patient, outstanding citizen, recent winner in a television contest on snakes, who was bitten accidentally by a coral snake Micrurus mipartitus. The poison of this snake is a macromolecule that induces complete depolarizing muscle blockade which, if not reverted, leads to death from respiratory failure. A group of social leaders in the region managed to obtain the specific anti-venom that was not produced in the country, as well as the mechanical ventilation equipment, a negative pressure “iron lung” and a Bird Mark 7 positive pressure device. Manual ventilation was initiated by the anaesthesia team with the support of the medical students. Then, with the Bird Mark 7, the patient survived under empirical “intensive” care after 17 days of respiratory depression and 33 days in the hospital. Voluntary contributions of the community in an effort to solve the clinical problem are narrated.
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The Amazon region reports the highest incidence of snakebite envenomings in Brazil. We aimed to describe the epidemiology of snakebites in the state of Amazonas and to investigate factors associated with disease severity and lethality. We used a nested case-control study, in order to identify factors associated with snakebite severity and mortality using official Brazilian reporting systems, from 2007 to 2012. Patients evolving to severity or death were considered cases and those with non-severe bites were included in the control group. During the study period, 9,191 snakebites were recorded, resulting in an incidence rate of 52.8 cases per 100,000 person/years. Snakebites mostly occurred in males (79.0%) and in rural areas (70.2%). The most affected age group was between 16 and 45 years old (54.6%). Fifty five percent of the snakebites were related to work activities. Age ≤15 years [OR=1.26 (95% CI=1.03-1.52); (p=0.018)], age ≥65 years [OR=1.53 (95% CI=1.09-2.13); (p=0.012)], work related bites [OR=1.39 (95% CI=1.17-1.63); (p6 hours [OR=1.73 (95% CI=1.45-2.07); (p6 hours [OR=2.01 (95% CI=1.15-3.50); (p=0.013)] were independently associated with the risk of death. Snakebites represent an occupational health problem for rural populations in the Brazilian Amazon with a wide distribution. These results highlight the need for public health strategies aiming to reduce occupational injuries. Most cases of severe disease occurred in the extremes of age, in those with delays in medical attention and those caused by Micrurus bites. These features of victims of snakebite demand adequate management according to well-defined protocols, including prompt referral to tertiary centres when necessary, as well as an effective response from surveillance systems and policy makers for these vulnerable groups.
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Envenoming snakebites are thought to be a particularly important threat to public health worldwide, especially in rural areas of tropical and subtropical countries. The true magnitude of the public health threat posed by snakebites is unknown, making it difficult for public health officials to optimize prevention and treatment. The objective of this work was to conduct a systematic review of the literature to gather data on snakebite epidemiology in the Amazon region and describe a case series of snakebites from epidemiological surveillance in the State of Amazonas (1974-2012). Only 11 articles regarding snakebites were found. In the State of Amazonas, information regarding incidents involving snakes is scarce. Historical trends show an increasing number of cases after the second half of the 1980s. Snakebites predominated among adults (20-39 years old; 38%), in the male gender (78.9%) and in those living in rural areas (85.6%). The predominant snake envenomation type was bothropic. The incidence reported by the epidemiological surveillance in the State of Amazonas, reaching up to 200 cases/100,000 inhabitants in some areas, is among the highest annual snakebite incidence rates of any region in the world. The majority of the cases were reported in the rainy season with a case-fatality rate of 0.6%. Snakebite envenomation is a great disease burden in the State of Amazonas, representing a challenge for future investigations, including approaches to estimating incidence under-notification and case-fatality rates as well as the factors related to severity and disabilities.
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O soro antipeçonhento específico para ser eficaz no tratamento dos acidentes causados pelas cobras corais deve ser administrado logo após a mordedura, uma vez que as neurotoxinas da peçonha são absorvidas muito rapidamente. Como isto não é sempre possível, outras formas de tratamento, além do soroterápico, devem ser empregadas para evitar a asfixia e morte do paciente. A administração da neostigmina e a respiração artificial são utilizadas com esse objetivo. A neostigmina restabelece a transmissão neuromuscular se o efeito da peçonha resultar de interação reversível de suas neurotoxinas com os receptores da placa terminal. É esse o mecanismo da ação das neurotoxinas da peçonha de M. frontalis de serpentes do centroeste e sul do Brasil, e da Argentina. Em conseqüência a neostigmina antagoniza o bloqueio neuromuscular produzido pela peçonha dessas serpentes e é muito eficaz no tratamento do envenenamento experimental de cães e símios. Na presente comunicação relatamos dois acidentes causados por M. frontalis, tratados com a administração do soro específico e da neostigmina. Nos dois pacientes a administração da neostigmina produziu regressão completa dos fenômenos de paralisia, confirmando sua eficiência demonstrada no tratamento do envenenamento experimental de animais.
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The aim of this study was to describe the epidemiological profile of snakebite accidents in the healthcare macroregion of the north of the State of Minas Gerais, Brazil. Database information on snakebite accidents covering the period from January 2002 to December 2006 was analyzed. It was found that 10,553 cases were notified, and that the samples were noticeably larger in the months of hot and rainy weather, in urban areas (54.1%), at ages less then 20 years (39.7%) and among men and students (53.1% and 29.1%) respectively. The lower limbs (feet, toes, legs and thighs) were the locations most affected (35.9%). The most prevalent snakes were in the genus Bothrops (82.9%) and most of the accidents were mild (66.2%). In this study, it was seen that the seasonality, urbanization and undernotification of the species involved in these accidents had a notable impact, along with seeking walk-in care. It is expected that the new data obtained from this sample may serve as the substrate for planning and implementing measures for healthcare surveillance.
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Micrurus is a monophyletic genus of venomous coral snakes of the family Elapidae. The ~80 recognized species within this genus are endemic to the Americas, and are distributed from southeastern United States to northern Argentina. Although relatively few bites are recorded due to their reclusive nature, semi-fossorial habits, and their occurrence in sparsely populated areas, coral snakes possess powerful venoms that target the cholinergic system and, if early treatment is missed, can cause neuromuscular paralysis, respiratory failure, and death by asphyxiation within hours of envenoming. The to-date proteomically characterized 18 micrurine venoms exhibit a puzzling phenotypic dichotomy, characterized by the toxin arsenal being dominated either by pre-synaptically acting PLA2s or post-synaptic 3FTxs, and a general, but imperfect, distributional pattern of these venom phenotypes along the North-South axis of the American continent. The lack of perfect phylogenetic clustering suggests that phylogeny may not be the sole factor driving the evolution of the divergent venom phenotypes across Micrurus venoms. To shed new light on the origin and expression pattern of the 3FTx/PLA2 venom dichotomy, we have conducted a comparative proteomics analysis of venoms from the Brazilian ribbon coral snake, Micrurus lemniscatus carvalhoi, sourced from different localities in the Brazilian states of São Paulo; the Caatinga coral snake, M. ibiboboca, from central Bahia state (Brazil); two Micrurus specimens of uncertain taxonomy collected in the Brazilian states of Alagoas and Rio de Janeiro; and the Western ribbon coral snake, M. l. helleri, from Leticia, the southernmost town of the Colombian Department of Amazonas. Venoms from São Paulo and Rio de Janeiro showed 3FTx-predominant phenotypes, while in venoms from Leticia, Alagoas and Bahia PLA2s represented the major toxin family. Comparative venom proteomics suggests that both Micrurus venom phenotypes exhibit a high degree of toxin evolvability. Mapping the 3FTx/PLA2 dichotomy across the Americas points to a phylogeographic pattern for venom phenotypes consistent with, but more complex than, the North-South distribution hypothesis anticipated in previous investigations. Biological significance New World coral snakes (Micrurus: Elapidae) produce potent venoms that target pre- and post-synaptically cholinergic nerve terminals resulting in neuromuscular paralysis, and in severe envenomings, may lead to death from asphyxiation by respiratory arrest. Presynaptic β-neurotoxins of group IA PLA2 protein subfamily and postsynaptic α-neurotoxins with 3FTx fold are the major components (>80%) of coral snake venoms. Micrurine venoms exhibit a puzzling phenotypic venom dichotomy, characterized by the dominant expression of either α- or β-neurotoxins. The distribution of these alternative compositional profiles has been fragmentarily studied both across Micrurus phylogeny and along the North-South axis of the genus radiation in the American continent, from southern United States to Northern Argentina. The unpredictability of the neurotoxin profile across the distribution range of the coral snakes represents a difficulty for applying the most appropriate treatment upon a coral snakebite. A deep knowledge of the phylogeographic distribution and the evolution of dichotomic Micrurus venoms would be useful for tracing the evolutionary path to their present day phenotypes, rationalizing the patchy cross-reactivity of current Micrurus antivenoms, and improving the efficacy of antivenoms to neutralize coral snake envenomings.
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Crotalus bites are considered a public health problem especially in Latin America. This study was performed to describe the epidemiology, spatial distribution and environmental determinants of Crotalus durissus bites in the Brazilian Amazon. Crotalus durissus envenomings official database included cases reported from 2010 to 2015. A total of 70,816 snakebites were recorded in the Amazon Region, 3058 (4.3%) cases being classified as crotalid, with a mean incidence rate of 11.1/100,000 inhabitants/year. The highest mean incidence rates were reported in Roraima, Tocantins and Maranhão. Area covered by water bodies, precipitation and soil humidity were negatively associated to rattlesnake encountering. Rattlesnake bites incidence was positively associated to tree canopy loss and altitude. In the Amazon, severe manifestations at admission, delayed medical assistance, lack of antivenom administration and ages ≥61 and 0–15 years were predictors of death in C. durissus snakebites. Spatial distribution of rattlesnake bites across the Brazilian Amazon showed higher incidence in areas of transition from the equatorial forest to the savanna, and in the savanna itself. Such results may aid focused policy-making in order to mitigate the burden, clinical complications and death as well as to manage Crotalus rattlesnake populations in the Brazilian Amazon.
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Snake envenoming represents a major burden for public health worldwide. In the Amazon, the official number of cases and deaths detected is probably underestimated because of the difficulty riverine and indigenous populations have reaching health centers in order to receive medical assistance. Thus, integrated analysis of health information systems must be used in order to improve adequate health policies. The aim of this work is to describe a series of deaths and identify risk factors for lethality from snakebites in the state of Amazonas, Brazil. All deaths from snakebites reported to the Brazilian Notifiable Diseases Surveillance System (SINAN) and to the Mortality Information System (SIM; ICD10-10th revision, X.29), from 2007 to 2015, were included. Variables were assessed by blocks with distal (ecological variables), intermediate (demographics) and proximal (clinical variables) components to identify predictors of case fatality. A total of 127 deaths from snakebites were recorded, with 58 pairs found through linkage of the SINAN and SIM databases (45.7%), 37 (29.1%) deaths found only in SINAN and 32 (25.2%) found only in the SIM. Deaths occurred mostly in males (95 cases; 74.8%) living in rural areas (78.6%). The most affected age group was the ≥61 years old (36 cases; 28.4%). Snakebites were presumably due to Bothrops snakes in 68.5% of the cases and Lachesis in 29.5% based on clinico-epidemiological diagnosis. A proportion of 26.2% of the cases received treatment over 24 h after the bite ocurred. On admission, cases were mostly classified as severe (65.6%). Overall, 28 patients (22.0%). Deceased without any medical assistance Antivenom was given to 53.5%. In the multivariate analysis, a distance from Manaus >300 km [OR = 3.40 (95%CI = 1.99-5.79); (p < 0.001)]; age ≥61 years [OR = 4.31 (95%CI = 1.22-15.21); (p = 0.023)] and Indigenous status [OR = 5.47 (95%CI = 2.37-12.66); (p < 0.001)] were independently associated with case fatality from snakebites. Severe snakebites [OR = 16.24 (95%CI = 4.37-60.39); (p < 0.001)] and a lack of antivenom administration [OR = 4.21 (95%CI = 1.30-13.19); (p = 0.014)] were also independently associated with case fatality. Respiratory failure/dyspnea, systemic bleeding, sepsis and shock were recorded only among fatal cases. In conclusion, i) death from snakebites was underreported in the mortality surveillance system; ii) older age groups living in remote municipalities and indigenous peoples were the population groups most prone to death; iii) lack or underdosage of antivenom resulted in higher case fatality and iv) systemic bleeding, circulatory shock, sepsis and acute respiratory failure were strongly associated to fatal outcome.
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Micrurus snakes, commonly known as coral snakes, are responsible for 0.4% of the snakebites envenomings in Brazil. In this report, we describe a case of envenoming by Micrurus averyi, the black-headed coral snake, recorded in the western Brazilian Amazon. To the best of our knowledge, this is the first published case perpetrated by this species. The major complaint of the patient was an intense local pain and paresthesia. Examination of the bite site revealed edema extending from the left foot up the left leg that was accompanied by erythema involving the foot and distal third of the leg. Systemic signs at admission included nausea and drooling. The patient was treated with 100 mL of coral snake antivenom and intravenous analgesics (dipyrone) and was discharged 48 h post-admission with no complaints. The patient showed more intense local edema than that generally described in several other cases of Micrurus bites in Brazil.
Article
Snakebite envenoming is a neglected tropical disease that kills >100,000 people and maims >400,000 people every year. Impoverished populations living in the rural tropics are particularly vulnerable; snakebite envenoming perpetuates the cycle of poverty. Snake venoms are complex mixtures of proteins that exert a wide range of toxic actions. The high variability in snake venom composition is responsible for the various clinical manifestations in envenomings, ranging from local tissue damage to potentially life-threatening systemic effects. Intravenous administration of antivenom is the only specific treatment to counteract envenoming. Analgesics, ventilator support, fluid therapy, haemodialysis and antibiotic therapy are also used. Novel therapeutic alternatives based on recombinant antibody technologies and new toxin inhibitors are being explored. Confronting snakebite envenoming at a global level demands the implementation of an integrated intervention strategy involving the WHO, the research community, antivenom manufacturers, regulatory agencies, national and regional health authorities, professional health organizations, international funding agencies, advocacy groups and civil society institutions.
Article
The application of proteomic tools to the study of snake venoms has led to an impressive growth in the knowledge about their composition (venomics), immunogenicity (antivenomics), and toxicity (toxicovenomics). About one-third of all venomic studies have focused on elapid species, especially those of the Old World. The New World elapids, represented by coral snakes, have been less studied. In recent years, however, a number of venomic studies on Micrurus species from North, Central, and South America have been conducted. An overview of these studies is presented, highlighting the emergence of some patterns and trends concerning their compositional, functional, and immunological characteristics. Results gathered to date, encompassing 18 out of the approximately 85 species of Micrurus, reveal a dichotomy of venom phenotypes regarding the relative abundance of the omnipresent phospholipases A2 (PLA2) and 'three-finger' toxins (3FTx): a group of species express a PLA2-predominant venom composition, while others display a 3FTx-predominant compositional pattern. These two divergent toxin expression phenotypes appear to be related to phylogenetic positions and geographical distributions along a North-South axis in the Americas, but further studies encompassing a higher number of species are needed to assess these hypotheses. The two contrasting phenotypes also show correlations with some toxic functionalities, complexity in the diversity of proteoforms, and immunological cross-recognition patterns. The biological significance for the emergence of a dichotomy of venom compositions within Micrurus, in some cases observed even among sympatric species that inhabit relatively small geographic areas, represents a puzzling and challenging area of research which warrants further studies.
Article
Context: In the Americas, the main representatives of the family Elapidae are coral snakes of the genus Micrurus, of which 33 species are in Brazil. They are the smallest cause of venomous snakebite in Brazil. We analyzed literature reports of coral snake bites in Brazil from 1867 to 2014, and provide a brief review of case series and reports of coral snake bites in the Americas in general. Methods: Only reports with clinical descriptions of envenomation were included. The variables recorded included identification of the offending snake, patient's age, sex, bite site, clinical manifestations, treatment, including antivenom and anticholinesterase drugs, and general evolution of the cases. 30 published reports describing bites caused by Micrurus spp. in Brazil were identified and involved 194 distinct cases. Since no information on the clinical manifestations was available in 44 cases, the analysis was restricted to 25 reports (150 cases). Results: Most patients were from southern (61.3%; primarily Santa Catarina state, 60%) and southeastern (20%) Brazil and were male (70.7%), with a median age of 27 years (interquartile interval = 18 to 40 years). The offending snakes were described in 59 cases (M. corallinus 36, M. frontalis 12, M. lemniscatus 5, M. hemprichi 2, M. filiformis 1, M. ibiboboca 1, M. spixii 1 and M. surinamensis 1); in 22 cases only the genus (Micrurus spp.) was reported. Of the 143 cases in which the bite site was recorded, most involved the hands (46.2%) and feet (26.6%). The main clinical features were local numbness/paresthesia (52.7%), local pain (48%), palpebral ptosis (33.3%), dizziness (26.7%), blurred vision (20.7%), weakness (20%), slight local edema (16%), erythema (16%), dysphagia (14.7%), dyspnea (11.3%), inability to walk (10.7%), myalgia (9.3%), salivation (8%) and respiratory failure (4.3%). Fang marks were described in 47.3% of cases and 14% of bites were classified as asymptomatic. A slight increase in total blood creatine kinase was reported in 3 children, suggesting mild myotoxicity. Therapeutic procedures included coral snake antivenom (77.3%), anticholinesterase drugs (6%), and mechanical ventilation (3.3%). Two patients reported in 1933 developed paralysis/respiratory failure and died 6 h and 17 h post-bite. Four more deaths probably caused by coral snakes were reported (2 in 1867, 1 in 1959, 1 in 1962), but no clinical information was available. Discussion: Neuromuscular blockade was the hallmark of systemic envenomation by Micrurus spp., with signs of myasthenia such as weakness and ptosis that may evolve to paralysis and respiratory failure. Local features, mainly numbness/paresthesia and pain, were frequently reported, with the pain being intense in some cases. Although myotoxicity has been detected in experimental studies with Micrurus spp. venoms, few human reports described laboratory findings compatible with myotoxicity. Conclusion: Most coral snake bites reported in Brazil were caused by M. corallinus and M. frontalis, with several patients showing signs of acute myasthenia. Serious complications such as paralysis with respiratory failure were observed but comparatively rare. The deaths occurred where respiratory support (mechanical ventilation) was unavailable when needed.
Article
The Micrurus genus is the American representative of Elapidae family. Micrurus spixii is endemic of South America and northern states of Brazil. Elapidic venoms contain neurotoxins that promote curare-mimetic neuromuscular blockage. In this study, biochemical and functional characterizations of M. spixii crude venom were performed and a new neurotoxic phospholipase A2 called MsPLA2-I was isolated. Micrurus spixii crude venom caused severe swelling in the legs of tested mice and significant release of creatine kinase (CK) showing its myotoxic activity. Leishmanicidal activity against Leishmania amazonensis (IC50 1.24 μg/mL) was also observed, along with antiplasmodial activity against Plasmodium falciparum, which are unprecedented for Micrurus venoms. MsPLA2-I with a Mr 12,809.4 Da was isolated from the crude venom of M. spixii. The N-terminal sequencing of a fragment of 60 amino acids showed 80% similarity with another PLA2 from Micrurus altirostris. This toxin and the crude venom showed phospholipase activity. In a mouse phrenic nerve-diaphragm preparation, M. spixii venom and MsPLA2-I induced the blockage of both direct and indirect twitches. While the venom presented a pronounced myotoxic activity, MsPLA2-I expressed a summation of neurotoxic activity. The results of this study make M. spixii crude venom promising compounds in the exploration of molecules with microbicidal potential. Copyright © 2015. Published by Elsevier Ltd.
Article
We gathered data on 39 victims of Eastern coral snake bite over a 12-year period. The most common situation resulting in snakebite was erroneous identification of the snake as the nonpoisonous scarlet king snake. While no patient died, several experienced severe envenomation, including bulbospinal respiratory paralysis. We found that neurologic symptoms may be delayed for 12 hours, and then may be precipitous. Envenomation occurs in 75% of the persons bitten by a coral snake. Antivenin is effective and should be intravenously administered early to patients who have been bitten by a positively identified coral snake, depending on the clinical presentation. (JAMA 1987;258:1615-1618)
Article
Three objective techniques used to obtain gauge-based daily precipitation analyses over global land areas are assessed. The objective techniques include the inverse-distance weighting algorithms of Cressman (1959) and Shepard (1968), and the optimal interpolation (OI) method of Gandin (1965). Intercomparisons and cross-validation tests are conducted to examine their performance over various parts of the globe where station network densities are different. The gauge data used in the examinations are quality controlled daily precipitation reports from roughly 16,000 stations over the global land areas that have been collected by the National Oceanic and Atmospheric Administration (NOAA) Climate Prediction Center (CPC). Data sources include daily summary files from the Global Telecommunication System (GTS), and the CPC unified daily gauge data sets over the contiguous United States (CONUS), Mexico, and South America. All three objective techniques are capable of generating useful daily precipitation analyses with biases of generally less than 1% over most parts of the global land areas. The OI method consistently performs the best among the three techniques for almost all situations (regions, seasons, and network densities). The Shepard scheme compares reasonably well with the OI, while the Cressman method tends to generate smooth precipitation fields with wider raining areas relative to the station observations. The quality of the gauge-based analyses degrades as the network of station observations becomes sparser, although the OI technique exhibits relatively stable performance statistics over regions covered by fewer gauges.
Article
Context: Envenomation by the Eastern coral snake is rare but may be associated with significant morbidity. While effective, acquisition of North American Coral Snake Antivenin (NACSAV) is difficult because production was discontinued for many years. Objective: The purpose of this study is to characterize coral snake exposures in Florida and determine the effects of varying treatment paradigms on patient outcomes. Methods: This study is an observational case series of cases received at Florida poison centers. Included cases were Eastern coral snake exposures occurring between January 1, 1998 and October 31, 2010. Excluded cases included those found to be unrelated or those not followed for at least 24 h post envenomation. Case comments were reviewed to obtain data. Comparisons were made between asymptomatic patients receiving empiric antivenom therapy (empiric group) and those asymptomatic patients who received antivenom upon developing signs of systemic envenomation (withhold group). Results: Of the 553 cases identified, 387 were included in the final analysis. According to case comments, 56.3% of patients had no reported systemic symptoms. Most commonly, patients were reported to have pain (40.6%), paresthesias (28.4%), nausea (12.7%), and emesis (11.4%). NACSAV was administered to 252 patients (65%). Of those patients receiving NACSAV, 18.25% were reported to have had an adverse reaction. Patients in the withhold group (n = 106) had significantly fewer minor, moderate, and major outcomes than patients in the empiric group (n = 134, p < 0.01). Discussion: While patients in the withhold group had favorable outcomes compared with those in the empiric group, this strategy cannot be applied to all patients presenting asymptomatic to healthcare facilities due to study limitations. Conclusion: Further studies are needed to determine what treatment strategy is most appropriate for asymptomatic patients presenting to healthcare facilities.