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Epidemiology and clinical features of South American rattlesnakes (Crotalus durissus) envenomation
Abstract
Foram estudados 249 casos de acidentes por cascavel sul-americana (Crotalus durissus) atendidos no HVB-IB, São Paulo, Brasil, de 1974 a 1990. Os acidentes foram mais comuns no período da tarde, nos meses de janeiro a abril e de outubro a dezembro. Dentre cem serpentes classificadas quanto à subespécie 99 eram C. d. terrificus. Pertenciam ao sexo masculino 80,7% dos pacientes. Os membros inferiores e superiores foram picados em, respectivamente, 66,4% e 29,2% dos casos. As manifestações clínicas mais freqüentes foram dor (61,0%) e edema (55,0%) no local da picada, ptose palpebral (75,9%), escurecimento da urina atribuível à mioglobinúria (38,6%) e mialgia (36,1%). Nove pacientes foram submetidos a diálise devido a insuficiência renal aguda (3,6%), três apresentavam insuficiência respiratória que motivou intubação e/ou traqueostomia e um apresentou acidente vascular cerebral isquêmico. A alteração da coagulação sanguínea ocorreu em 48,1% dos pacientes. Oito amostras de sangue colhidas horas após a picada mostraram leucocitose sendo 6 com desvio a esquerda e, nos dias subseqüentes, tendência à normalização do número de leucócitos e aparecimento de eosinofilia. Atividade sérica da creatinoquinase apresentou-se aumentada em 20 dentre 21 pacientes, sendo maior no final das primeiras 24 horas após a picada, chegando a 2.377 vezes o valor de referência. A letalidade foi de 0,8%.
... Local manifestations include usually mild or absent pain and edema, with erythema and paresthesia [33][34][35]. Neurological systemic manifestations appear in the first hours after the bite, and characterize the myasthenic facies (Rosenfeld neurotoxic facies) evidenced by uni-or bilateral palpebral ptosis, facial muscle flaccidity, pupillary diameter alteration, ophthalmoplegia, blurred vision, and/or diplopia [13,[34][35][36]. Other manifestations, such as difficulty in swallowing, velopalatine paralysis, increased vomiting reflex, and taste and smell alterations may also be observed in those more severe cases [17]. ...
... Local manifestations include usually mild or absent pain and edema, with erythema and paresthesia [33][34][35]. Neurological systemic manifestations appear in the first hours after the bite, and characterize the myasthenic facies (Rosenfeld neurotoxic facies) evidenced by uni-or bilateral palpebral ptosis, facial muscle flaccidity, pupillary diameter alteration, ophthalmoplegia, blurred vision, and/or diplopia [13,[34][35][36]. Other manifestations, such as difficulty in swallowing, velopalatine paralysis, increased vomiting reflex, and taste and smell alterations may also be observed in those more severe cases [17]. ...
... Laboratory parameters all remained within normal limits from the time of hospital admission through the time of discharge, except for CK and the patient did not experience any coagulopathy during the hospital course of stay. During a study conducted by Jorge et al. [34], 3 patients developed respiratory failure (of 249 cases analyzed). Oliveira Neto et al. [56] analyzed the pulmonary function in an experimental model of acute lung injury (in mice) induced by the C. durissus cascavella venom and the venom caused mechanical and histopathological changes in the lung tissue. ...
Snakebite envenoming is a neglected public health issue in many tropical and subtropical countries. To diagnosis and treat snakebites may be challenging to health care personnel since sufficient information has not been yet provided. This review presents the clinical, therapeutic, and laboratory aspects of Crotalus durissus (South American rattlesnakes) victims. The clinical setting may show local effects such as little or no pain, mild edema, and recurrent erythema. In contrast, the systemic effects may be quite remarkable, such as changes due to neurological damage, intense rhabdomyolysis, incoagulability of the blood, and variations in the peripheral blood elements. The main complication is acute kidney injury. The appropriate treatment depends mainly on the correct recognition of the aggressor snake and the symptoms expressed by the victim. Rattlesnake venom can cause irreparable damage and lead to death. Therefore, a prompt diagnosis allows the immediate onset of proper serotherapy.
... To obtain a comprehensive proteomic characterization of the effects of the C. d. terrificus venom in mice cerebellums, which is responsible for equilibrium, coordination, balance, motor learning, motor memory, and motor consolidation, we used high-resolution mass spectrometrybased proteomics to analyze mice cerebellums injected with the venom at different time points over the period when patients seek the hospital after a snakebite [18]. The results indicated effects not previously described in the literature, such as the perturbation of proteins involved in the blood brain barrier, synaptic transmission, and tissue damage. ...
Snake envenomation is a common but neglected disease that affects millions of people around the world annually. Among venomous snake species in Brazil, the tropical rattlesnake (Crotalus durissus terrificus) accounts for the highest number of fatal envenomations and is responsible for the second highest number of bites. Snake venoms are complex secretions which, upon injection, trigger diverse physiological effects that can cause significant injury or death. The components of C. d. terrificus venom exhibit neurotoxic, myotoxic, hemotoxic, nephrotoxic, and cardiotoxic properties which present clinically as alteration of central nervous system function, motor paralysis, seizures, eyelid ptosis, ophthalmoplesia, blurred vision, coagulation disorders, rhabdomyolysis, myoglobinuria, and cardiorespiratory arrest. In this study, we focused on proteomic characterization of the cardiotoxic effects of C. d. terrificus venom in mouse models. We injected venom at half the lethal dose (LD50) into the gastrocnemius muscle. Mouse hearts were removed at set time points after venom injection (1 h, 6 h, 12 h, or 24 h) and subjected to trypsin digestion prior to high-resolution mass spectrometry. We analyzed the proteomic profiles of >1300 proteins and observed that several proteins showed noteworthy changes in their quantitative profiles, likely reflecting the toxic activity of venom components. Among the affected proteins were several associated with cellular deregulation and tissue damage. Changes in heart protein abundance offer insights into how they may work synergistically upon envenomation.
Significance
Venom of the tropical rattlesnake (Crotalus durissus terririficus) is known to be neurotoxic, myotoxic, nephrotoxic and cardiotoxic. Although there are several studies describing the biochemical effects of this venom, no work has yet described its proteomic effects in the cardiac tissue of mice. In this work, we describe the changes in several mouse cardiac proteins upon venom treatment. Our data shed new light on the clinical outcome of the envenomation by C. d. terrificus, as well as candidate proteins that could be investigated in efforts to improve current treatment approaches or in the development of novel therapeutic interventions in order to reduce mortality and morbidity resulting from envenomation.
... To obtain a comprehensive proteomic characterization of the effects of the C. d. terrificus venom in mice cerebellums, which is responsible for equilibrium, coordination, balance, motor learning, motor memory, and motor consolidation, we used high-resolution mass spectrometrybased proteomics to analyze mice cerebellums injected with the venom at different time points over the period when patients seek the hospital after a snakebite [18]. The results indicated effects not previously described in the literature, such as the perturbation of proteins involved in the blood brain barrier, synaptic transmission, and tissue damage. ...
Snake envenomation is responsible for more than 130,000 deaths worldwide. In Brazil, the Crotalus rattlesnake is responsible for the second largest number of accidental snake bites in the country. Although there are many descriptions of the clinical and biochemical effects of Crotalus envenoming, there are few works describing the molecular events in the central nervous system of an organism due to envenomation. In this study, we analyzed the proteomic effect of Crotalus durissus terrificus snake venom on mice cerebellums. To monitor the envenomation over time, changes in the protein abundance were evaluated at 1 h, 6 h, 12 h and 24 h after venom injection by mass spectrometry. The analysis of the variation of over 4600 identified proteins over time showed a reduction in components of inhibitory synapse signaling, oxidative stress, and maintenance of neuronal cells, which paralleled increasing tissue damage and apoptosis factors. These analyses revealed the potential protein targets of the C. d. terrificus venom on the murine cerebellum, showing new aspects of the snake envenomation effect. These data may contribute to new therapeutic approaches (i.e., approaches directed at protein targets affected by the envenomation) on the treatment of envenomation by the neurotoxic C. d. terrificus snake venom.
Significance
Snakebites are a neglected global health problem that affects mostly rural and tropical areas of developing countries. It is estimated that over 5.4 million people are bitten by snakes each year, from which 2.7 million people are bitten by venomous snakes, resulting in disabilities such as amputations and in some cases leading to death.
The C. d. terrificus snake is the most lethal snake in Brazil. Studying the molecular changes upon envenomation in a specific tissue may lead to a better understanding of the envenomation process by C. d. terrificus snakebites.
... For example, in a recent review, Frare and colleagues described the delayed and variable clinical manifestations of Crotalus durissus envenoming. The summarized clinical reports describe muscle and kidney damage, neurotoxicity and hemolytic/coagulopathic pathologies to varying degrees [36][37][38]. These variations in clinical presentation may be related to differences in venom composition and effects that vary with season, locality, and even with sub-populations of the same species of Crotalus [39]. ...
The active components of snake venoms encompass a complex and variable mixture of proteins that produce a diverse, but largely stereotypical, range of pharmacologic effects and toxicities. Venom protein diversity and host susceptibilities determine the relative contributions of five main pathologies: neuromuscular dysfunction, inflammation, coagulopathy, cell/organ injury, and disruption of homeostatic mechanisms of normal physiology. In this review, we describe how snakebite is not only a condition mediated directly by venom, but by the amplification of signals dysregulating inflammation, coagulation, neurotransmission, and cell survival. Although venom proteins are diverse, the majority of important pathologic events following envenoming follow from a small group of enzyme-like activities and the actions of small toxic peptides. This review focuses on two of the most important enzymatic activities: snake venom phospholipases (svPLA2) and snake venom metalloproteases (svMP). These two enzyme classes are adept at enabling venom to recruit homologous endogenous signaling systems with sufficient magnitude and duration to produce and amplify cell injury beyond what would be expected from the direct impact of a whole venom dose. This magnification produces many of the most acutely important consequences of envenoming as well as chronic sequelae. Snake venom PLA2s and MPs enzymes recruit prey analogs of similar activity. The transduction mechanisms that recruit endogenous responses include arachidonic acid, intracellular calcium, cytokines, bioactive peptides, and possibly dimerization of venom and prey protein homologs. Despite years of investigation, the precise mechanism of svPLA2-induced neuromuscular paralysis remains incomplete. Based on recent studies, paralysis results from a self-amplifying cycle of endogenous PLA2 activation, arachidonic acid, increases in intracellular Ca2+ and nicotinic receptor deactivation. When prolonged, synaptic suppression supports the degeneration of the synapse. Interaction between endothelium-damaging MPs, sPLA2s and hyaluronidases enhance venom spread, accentuating venom-induced neurotoxicity, inflammation, coagulopathy and tissue injury. Improving snakebite treatment requires new tools to understand direct and indirect effects of envenoming. Homologous PLA2 and MP activities in both venoms and prey/snakebite victim provide molecular targets for non-antibody, small molecule agents for dissecting mechanisms of venom toxicity. Importantly, these tools enable the separation of venom-specific and prey-specific pathological responses to venom.
... Brazilian epidemiological research of ophidian accidents began in São Paulo, with doctor Vital Brazil (Brazil, 1911). Thereafter, several studies regarding ophidian accidents epidemiology have been performed by analyzing medical records (JORGE; RIBEIRO, 1992;RIBEIRO et al., 1995;CAIAFFA et al., 1997;BORGES et al., 1999;CARDOSO, 2000;AVILA-AGÜERO et al., 2001;FRANCO et al., 2001;SILVA et al., 2003;PINHO et al., 2004;MISE et al., 2007;BONAN et al., 2010). Ribeiro and Jorge (1997) performed the first study about aspects of snakebite epidemiology in Triângulo Mineiro region, Minas Gerais. ...
Ophidian accidents constitute a serious problem of public health in the tropical countries. In Central and South America, most of the accidents are caused by Bothrops (90.5%), followed by the Crotalus (7.7%), Lachesis (1.4%) and Micrurus (0.4%) genus. The aim of this work was to evaluate clinical-epidemiological aspects of ophidian accidents reported and treated at the Clinical Hospital at Federal University of Uberlândia, in the central region of Brazil. In this study, 641 medical records from January 1999 to December 2013 were analyzed. The results showed that the accidents were more common in the afternoon, from October to April. The major bite occurrence frequency was attributed to the Bothrops (54.76%), followed by Crotalus (30.58%) and Micrurus (1.40%) snakes. Most of the victims were males (80.34%). The main anatomical regions bitten were the lower and upper limbs, 65.67% and 30.58%, respectively. Approximately 80% of the victims were treated in the first 6 hours after the accident. © 2014, Universidade Federal de Uberlandia. All Rights Reserved.
Snakebite envenomations are classified as Category A Neglected Tropical Diseases by the World Health Organization. In Brazil, 405 snake species are distributed among 11 families, with the genera Bothrops and Crotalus being the most studied and main responsible for severe and lethal envenomations. In the country, Crotalus genus (i.e., rattlesnakes) is represented by Crotalus durissus species, showing seven different subspecies distributed along the country, including Crotalus durissus ruruima, which inhabits Roraima, the Brazilian nothermost state from Amazon forest. Here, we report a fatal case of a severe envenomation following a rattlesnake bite. The patient presented classic crotalic neurological signs and symptoms such as ptosis, drooling of saliva, sluggishness, macroscopic hematuria, and oliguria, which evolved to acute kidney failure (AKF) and hemodynamic instability. Although the patient was treated with the specific antivenom therapy, the severe envenomation resulted in three cardiac arrests and death of the victim in less than 38 h. This study discusses the causes of the patient death, the features of rattlesnake venom-induced AKF, and shows evidences that the Brazilian crotalic antivenom should be improved to treat rattlesnake envenomations caused by C. d. ruruima venom in Roraima state.
Toxic effects triggered by crotalic envenoming are mainly related to crotoxin (CTX), composed of a phospholipase A2 (CB) and a subunit with no toxic activity (CA). Camelids produce immunoglobulins G devoid of light chains, in which the antigen recognition domain is called VHH. Given their unique characteristics, VHHs were selected using Phage Display against CTX from Crotalus durissus terrificus. After three rounds of biopanning, four sequence profiles for CB (KF498602, KF498603, KF498604, and KF498605) and one for CA (KF498606) were revealed. All clones presented the VHH hallmark in FR2 and a long CDR3, with the exception of KF498606. After expressing pET22b-VHHs in E. coli, approximately 2 to 6 mg of protein per liter of culture were obtained. When tested for cross-reactivity, VHHs presented specificity for the Crotalus genus and were capable of recognizing CB through Western blot. KF498602 and KF498604 showed thermostability, and displayed affinity constants for CTX in the micro or nanomolar range. They inhibited in vitro CTX PLA2 activity, and CB cytotoxicity. Furthermore, KF498604 inhibited the CTX-induced myotoxicity in mice by 78.8%. Molecular docking revealed that KF498604 interacts with the CA–CB interface of CTX, seeming to block substrate access. Selected VHHs may be alternatives for the crotalic envenoming treatment.
Snakebites can cause life-threatening injuries, sometimes requiring intensive care. The most important snakebites occurring in Latin America are provoked by species of the family Viperidae (Bothrops, Crotalus, and Lachesis) and Elapidae (genus Micrurus). Viperid venoms induce prominent local tissue pathology, which may lead to permanent sequelae and systemic disturbances associated with coagulopathies, bleeding, hemodynamic alterations, and acute kidney injury. Elapid snake venoms, and South American rattlesnake venoms, induce neurotoxic manifestations associated with paralysis of various muscles, including respiratory muscles. Treatment of envenomation is based on parenteral administration of antivenoms. Severely envenomed patients need an adequate life support therapy such as treatment of shock, assisted ventilation, and renal therapy replacement.
Snakebites can cause life-threatening injuries,
sometimes requiring intensive care. The most
important snakebites occurring in Latin America
are provoked by species of the family Viperidae
(Bothrops, Crotalus, and Lachesis) and Elapidae
(genus Micrurus). Viperid venoms induce prominent
local tissue pathology, which may lead to
permanent sequelae and systemic disturbances
associated with coagulopathies, bleeding, hemodynamic
alterations, and acute kidney injury. Elapid
snake venoms, and South American
rattlesnake venoms, induce neurotoxic manifestations
associated with paralysis of various muscles,
including respiratory muscles. Treatment of
envenomation is based on parenteral administration
of antivenoms. Severely envenomed patients
need an adequate life support therapy such as
treatment of shock, assisted ventilation, and
renal therapy replacement.
Crotamine is one of the main constituents of the venom of the South American rattlesnake Crotalus durissus terrificus. Here we sought to investigate the inflammatory and toxicological effects induced by the intrahippocampal administration of crotamine isolated from Crotalus whole venom. Adult rats received an intrahippocampal infusion of crotamine or vehicle and were euthanized 24 h or 21 days after infusion. Plasma and brain tissue were collected for biochemical analysis. Complete blood count, creatinine, urea, glutamic oxaloacetic transaminase (GOT), glutamic pyruvic transaminase (GPT), creatine-kinase (CK), creatine kinase-muscle B (CK-MB) and oxidative parameters (assessed by DNA damage and micronucleus frequency in leukocytes, lipid peroxidation and protein carbonyls in plasma and brain) were quantified. Unpaired and paired t-tests were used for comparisons between saline and crotamine groups, and within groups (24 h vs. 21 days), respectively. After 24 h crotamine infusion promoted an increase of urea, GOT, GPT, CK, and platelets values (p ≤ 0.01), while red blood cells, hematocrit and leukocytes values decreased (p ≤ 0.01). Additionally, 21 days after infusion crotamine group showed increased creatinine, leukocytes, TBARS (plasma and brain), carbonyl (plasma and brain) and micronucleus compared to the saline-group (p ≤ 0.01). Our findings show that crotamine infusion alter hematological parameters and cardiac markers, as well as oxidative parameters, not only in the brain, but also in the blood, indicating a systemic pro-inflammatory and toxicological activity. A further scientific attempt in terms of preserving the beneficial activity over toxicity is required.
São analisados três pacientes que apresentaram comprometimento da função respiratória após acidente por Crotalus durissus. As manifestações respiratórias surgiram nas primeiras 48 horas após a picada do ofídio e consistiram de dispnéia, taquipnéia, uso da musculatura acessória da respiração (casos 1 e 2) e batimento das aletas nasais (caso 2). Dois pacientes (casos 1 e 2) apresentaram insuficiência respiratória aguda. O diagnóstico desta complicação no caso 1 foi clínico pois o paciente apresentou apnéia. O paciente do caso 2, 24 horas após o acidente ofídico apresentou dificuldade respiratória intensa e períodos de apnéia sendo intubado, permanecendo em respiração espontânea. Houve agravamento dos sinais clínicos de insuficiência respiratória e a determinação de pH e gases do sangue arterial mostrou em relação ao exame inicial elevação da pressão parcial de gás carbônico (40 mmHg para 50,3 mm Hg) caracterizando insuficiência ventilatória aguda. Ambos foram tratados com emprego de ventilação artificial mecânica, tendo o paciente do caso 1 permanecido no ventilador durante 33 dias e o do caso 2 durante 15 dias. Ambos desenvolveram insuficiência renal aguda, necessitaram de diálise peritoneal e recuperaram a função renal. A paciente do caso 3, apesar dos sintomas e sinais de comprometimento respiratório não apresentou alterações do pH e gases arteriais. Espirometria realizada 58 horas após o acidente mostrou capacidade vital forçada (CVF) e volume espirado no primeiro segundo (VEF1) abaixo do previsto (60 e 67% respectivamente). As espirometrias realizadas nos dias subseqüentes evidenciaram melhora progressiva destes parâmetros. No 10º dia após o acidente constatou-se aumento de 20% da CVF e de 17% do VEF1 comparativamente ao exame inicial. A relação entre VEF1 e a CVF manteve-se praticamente inalterada e em valores próximos ao previsto, caracterizando distúrbio ventilatório do tipo restritivo. O comprometimento respiratório nestes pacientes foi atribuído à ação da crotoxina na musculatura respiratória desde que não se encontravam presentes outras condições etiológicas que pudessem ocasioná-lo como uremia avançada, atelectasias, infecção pulmonar, hipopotassemia, congestão e edema pulmonar agudo.Three patients presented respiratory abnormalities following Crotalus durissus snakebite. These abnormalities appeared in the first 48 h after the snake bite and consisted of dyspnea, tachypnea, use of accessory muscles of respiration (cases 1 and 2) and flaring of the nostrils (case 2). Cases 1 and 2 developed acute respiratory failure. Case 2, 24 h after the snakebite presented difficult breathing and periods of apnea. He was intubated in the emergency room and transferred to the intensive case unit where he arrive with spontaneous breathing. His respiratory pattern worsened and measurement of arterial pH and blood gases showed metabolic and respiratory acidosis with partial carbon dioxide pressure increasing from 40 to 50,3 mmHg compatible with acute ventilatory failure. Both patients needed mechanical ventilation. Weaning from the ventilator was accomplished after 33 days in case 1 and after 15 days in case 2. Both patients also presented acute renal failure treated with peritoneal dialysis with full recovery of the renal function. Measurements of forced vital capacity (FVC) and forced expiratory volume in the first second (FEV 1.0) was carried out 58 hours after the snakebite in case 3. Both FVC and FEV 1.0 were reduced in relation to the predicted values (60 and 67% respectively) but the ratio FEV 1.0/FVC was in the normal range. These findings were compatible with a restrictive pattern of ventilatory failure. Serial measurements showed progressive increase of both FVC and FEV 1.0 reaching 72 and 79% of the predicted values, respectively, in the 10 th day after the snakebite. Case 1 developed deep coma attributed to cerebral hypoxia suffered during several episodes of seizure and died of pulmonary infection 10 months after the snakebite. Cases 2 and 3 recovered completely. These respiratory abnormalities were attributed to the action of crotoxin in the respiratory muscles since the patients did not present complications such as severe uremia, atelectasis, pulmonary infection, cardiac failure and pulmonary edema that could also produce them.
Forty patients with a diagnosis of snake bite were studied at the Infectious and Parasitic Disease Service of the Faculty of Medicine of Botucatu. Thirty were males and 10 females, ranging in age from 16 to 70 years. All were farm laborers and 35 of them were bitten in the lower limbs. Two of the 9 patients seen more than 6 hours after the bite died. The low mortality rate (5%) observed could be explained by the early care provided, by the use of appropriate doses of anti-crotalus serum, parenteral hydration, urine alkalinization with sodium bicarbonate and induction of osmotic diuresis with a mannitol solution. Anatomopathological examination of one of the patients who died revealed extensive hepatic necrosis. The authors discuss the possibility of the effect of a factor of snake venom in the genesis of hepatic necrosis and in the increased transaminase levels.
Following the bite of Crotalus durissus terrificus, an 11-year-old boy developed afibrinogenemia and high output acute renal failure. His platelet count remained within normal limits. He was treated with epsilon aminocaproic acid and whole fresh blood transfusion, with full recovery from afibrinogenemia 40 hours after the beginning of these measures and 75 hours after the snake bite. No hemorrhagic disturbances were present. The acute renal failure was treated conservatively, and the patient recovered 12 days after the snake bite and was discharged from hospital with no sequelae.
The venom of the South American rattlesnake Crotalus durissus terrificus was originally reported to have a pathophysiological activity mainly involving hemolysis and neurotoxicity. The systemic myotoxic action of this venom was demonstrated in 1985. In the present paper we report clinical and laboratory data concerning three patients bitten by C. durissus terrificus and treated at the University Hospital of Ribeirão Preto, University of São Paulo. The normal haptoglobin levels detected in the serum of these patients during the first 48 hr after the accident, as well as the absence of hemoglobin in darkened urine samples as evaluated by immunodiffusion against anti-hemoglobin serum, rule out the occurrence of intravascular hemolysis. These data permit us to conclude that the signs and symptoms observed in human envenomation with C. durissus terrificus are due to a myotoxic and neurotoxic action of the venom.
The venom of the South American rattlesnake Crotalus durissus terrificus was first reported to have mainly haemolytic and neurotoxic physiopathological activities. Later studies demonstrated the systemic myotoxic action of the venom, characterized by the release of myoglobin from damaged skeletal muscle into serum and urine, and a recent report ruled out the presence of intravascular haemolysis in 3 patients, one child and 2 adults. The present paper describes the clinical-laboratory evolution of 10 children bitten by C. durissus terrificus; 2 developed acute renal failure and one died. The myotoxic activity of the venom was evaluated by measuring serum lactic dehydrogenase, creatine kinase and aspartate aminotransferase, by detection of myoglobin in serum and urine, and by muscle biopsy. Haemolytic activity was evaluated by serial measurements of serum haemoglobin and haptoglobin and by detection of urine haemoglobin. We conclude that the signs and symptoms exhibited by patients bitten by C. durissus terrificus are due only to the myotoxic and neurotoxic action of the venom. The only patients with major morbidity were those who initially received subcutaneous antivenin and did not receive definitive antivenin therapy until later.
A thrombin-like enzyme was isolated in 6% yield from the venom of Crotalus durissus terrificus by ammonium sulfate precipitation followed by gel filtration on Sephadex G-75 and finally affinity chromatography on Sepharose-1,4-butanediol-diglycyl-p-aminobenzamide eluted with 0.15 M benzamidine. The enzyme behaved like a single component on SDS-PAGE corresponding to a molecular weight of 34 kDa. The specific activity of the enzyme toward bovine fibrinogen was 71 NIH U/mg protein. The pH optimum for the coagulation of human fibrinogen was 8.0. The enzyme hydrolyzes the alpha-chain of fibrinogen, has amidase activity on L-arginine-p-nitroanilide and L-arginine-7-amido-4-methyl-coumarin amino terminal blocked peptides and presents esterolytic activity on N-alpha-tosyl-L-arginine-methylester.
The venom of the Brazilian rattlesnake Crotalus durissus terrificus is know to have hemolytic and neurotoxic physiopathological activities which may cause acute renal failure with hemoglobinuria and/or methemoglobinuria. As far as we know, no report has been published on the ability of the venom of this rattlesnake species to cause rhabdomyolysis. In the present paper we demonstrate that the venom of Brazilian snakes of the genus Crotalus can induce systemic myonecrosis. Clinical, laboratory and anatomo-pathological data for two patients referred to the University Hospital of the Faculty of Medicine of Ribeirão Preto, University of São Paulo, 24 hr after a rattlesnake bite, are presented. In both cases, exaggerated elevation of serum levels of the enzymes creatine phosphokinase, lactate dehydrogenase and glutamic-oxaloacetic transaminase were detected, as well as data suggesting acute hypercatabolic renal failure. Immunoelectrophoresis of the serum and urine of these patients, carried out against specific anti-myoglobin serum (Behringwerke), demonstrated myoglobinemia and myoglobinuria, confirming injury to muscle tissue. Electron microscopy of a calf muscle biopsy taken from the leg contralateral to the bite from one patient revealed foci of myonecrosis.