Envenoming by Bothrops jararaca in Brazil: association between venom antigenaemia and severity at admission to hospital

Intramuscular injection of Bothrops jararaca venom provoked acute kidney injury (AKI): Underpinned by impaired renal filtration, Na+ handling, and tissue damage

Globally, about 2.5 million people are victims of snakebites annually. In Brazil, the most clinically relevant snake is the Bothrops jararaca. The symptoms of envenomation are acute inflammation at the bite site and bleeding disorders. Despite kidney failure being the main cause of death after envenomation, kidney damage is not completely understood, and there are no clinically representative in vivo models. This work aimed to characterize the acute kidney injury (AKI) induced by intramuscular injection (IM) of Bothrops jararaca (Bjc) venom in male Wistar rats. The control group received 0.9% saline solution. Three doses of venom (3.5, 6.0, and 8.0 mg/kg) were administered IM into the posterior region of the right knee. After the injection, the rats were kept in metabolic cages. The following parameters were analyzed after 24 h: the extent of muscle damage and kidney damage (urinary creatinine, proteinuria, plasma creatinine, and renal tissue histology). All rats presented a hemorrhagic lesion at the injection site in a dose-dependent manner. Biochemical parameters indicated kidney damage: plasma creatinine accumulation, decreased glomerular filtration rate, albuminuria and proteinuria, and disturbance in Na+ homeostasis. Histological analyses showed glomerular injury, tissue discontinuity more evident in the cortex and tubular dilatation, and collagen deposition. The decline in renal function and tissue damage indicated the occurrence of AKI. Therefore, a Bjc venom-induced in vivo model of renal injury has been established for future studies.

Ultrasound and Gold Nanoparticles Improve Tissue Repair for Muscle Injury Caused by Snake Venom

OBJECTIVE

To develop a treatment that enhances recovery from envenomation-induced lesions caused by Bothrops jararaca venom by using ultrasound in combination with gold nanoparticles (GNPs).

METHODS

A total of 108 Swiss mice were arranged into nine groups. The animals underwent necrotic induction with 250 µg B. jararaca venom (BjV) and were treated with ultrasound (U) at 1 MHz frequency at an intensity of 0.8 W/cm² for 5 min, 30 mg/L GNPs, and anti-bothropic serum (AS) in the following combinations: saline solution (SS); BjV; BjV + AS; BjV + AS + U; BjV + GNPs + AS; BjV + GNPs + AS + U; BjV + GNPs; BjV + GNPs + U; and BjV + U. The necrotic area, histology, oxidative stress, oxidative damage, and anti-oxidant system were assessed to evaluate the effects of the treatments.

RESULTS

Treatments that included GNPs, U, and/or AS demonstrated reductions in necrotic area, increases in angiogenesis and fibroblast means, decreases in inflammatory infiltrates, and improvements in collagen synthesis. Additionally, there was an increase in oxidants and oxidant damage within the gastrocnemius muscle, along with an increase in anti-oxidants. Furthermore, systemic effects appear to have been achieved, improving the anti-oxidant system at the cardiovascular and renal levels.

CONCLUSION

The use of GNPs and U may be effective at treating lesions caused by B. jararaca snake venom.

Venom Composition of Neglected Bothropoid Snakes from the Amazon Rainforest: Ecological and Toxinological Implications

Snake venoms have evolved in several families of Caenophidae, and their toxins have been assumed to be biochemical weapons with a role as a trophic adaptation. However, it remains unclear how venom contributes to the success of venomous species for adaptation to different environments. Here we compared the venoms from Bothrocophias hyoprora, Bothrops taeniatus, Bothrops bilineatus smaragdinus, Bothrops brazili, and Bothrops atrox collected in the Amazon Rainforest, aiming to understand the ecological and toxinological consequences of venom composition. Transcriptomic and proteomic analyses indicated that the venoms presented the same toxin groups characteristic from bothropoids, but with distinct isoforms with variable qualitative and quantitative abundances, contributing to distinct enzymatic and toxic effects. Despite the particularities of each venom, commercial Bothrops antivenom recognized the venom components and neutralized the lethality of all species. No clear features could be observed between venoms from arboreal and terrestrial habitats, nor in the dispersion of the species throughout the Amazon habitats, supporting the notion that venom composition may not shape the ecological or toxinological characteristics of these snake species and that other factors influence their foraging or dispersal in different ecological niches.

Systemic toxicity of snake venom metalloproteinases: Multi-omics analyses of kidney and blood plasma disturbances in a mouse model

Snakebite envenomation is classified as a Neglected Tropical Disease. Bothrops jararaca venom induces kidney injury and coagulopathy. HF3, a hemorrhagic metalloproteinase of B. jararaca venom, participates in the envenomation pathogenesis. We evaluated the effects of HF3 in mouse kidney and blood plasma after injection in the thigh muscle, mimicking a snakebite. Transcriptomic analysis showed differential expression of 31 and 137 genes related to kidney pathology after 2 h and 6 h, respectively. However, only subtle changes were observed in kidney proteome, with differential abundance of 15 proteins after 6 h, including kidney injury markers. N-terminomic analysis of kidney proteins showed 420 proteinase-generated peptides compatible with meprin specificity, indicating activation of host proteinases. Plasma analysis revealed differential abundance of 90 and 219 proteins, respectively, after 2 h and 6 h, including coagulation-cascade and complement-system components, and creatine-kinase, whereas a semi-specific search of N-terminal peptides indicated activation of endogenous proteinases. HF3 promoted host reactions, altering the gene expression and the proteolytic profile of kidney tissue, and inducing plasma proteome imbalance driven by changes in abundance and proteolysis. The overall response of the mouse underscores the systemic action of a hemorrhagic toxin that transcends local tissue damage and is related to known venom-induced systemic effects.

Reports of Doses Administered and Adverse Reactions to Snake Antivenom Used in Uruguay in 2018

In Uruguay, around 60 cases of snakebite accidents occur every year that need to be treated with specific antivenom. They are caused by two snakes of Bothrops genus: Bothrops alternatus and Bothrops pubescens. Snakebite accidents are mandatory notification events, allowing the acquisition of an accurate registry and a fluent communication with the health care services. The aim of this study is to analyze and report the doses administered to achieve the neutralization of the venom and the adverse reactions caused by snake antivenoms used in Uruguay in 2018, when a change was made in the type of antivenom available. In this year, Uruguay started to use the BIOL® antivenom (lyophilized) and this use coexists with traditional antivenom liquid forms (Vital Brazil and Malbran). The number of patients treated with heterologous BIOL® antivenom were 28 and the ones treated with heterologous solutions Malbran and Vital Brazil antivenoms were 21. The initial dose of BIOL antivenom was 8 vials instead of 4 vials regularly used with the others antivenoms and it achieved the neutralization of most cases (27/28 cases). Early adverse reactions were detected in 4 patients (3 in children) treated with BIOL antivenom and there were no adverse reactions in those treated with Malbran or Vital Brazil antivenoms. Lyophilized antivenom BIOL is being used widely in Uruguay without major complications.

Acute kidney failure following severe viper envenomation: clinical, biological and ultrasonographic aspects

BACKGROUND

Acute kidney injury (AKI) is a frequent complication of snakebite envenomation, which is still little known in sub-Saharan Africa. This study aims to describe the clinical, biological and ultrasonographic aspects of AKI following severe snakebite envenomation managed in the intensive care unit.

METHOD

A prospective observational survey was performed in Benin over a period of 18 months. All patients suffering severe snakebite envenomation (SBE) were included. The diagnosis of AKI was made using the KDIGO criteria. Kidney ultrasound exam was performed in all patients to assess internal bleeding and morphological and structural abnormalities of the kidneys.

RESULTS

Fifty-one cases of severe SBE were included. All patients presented inflammatory syndrome and showed abnormal WBCT whereas bleeding was found in 46 of them (90%). The median time to hospital presentation was three days. The majority of patients were male (M/F sex ratio = 1.55) and the median age was 26. Sixteen patients (31%) showed AKI according to the KDIGO criteria. Severe AKI (KDIGO stage 2 and 3) was observed in three patients, including one stage 2 and two stage 3. Kidney ultrasound revealed three cases of kidney capsular hematoma (6%), two cases of kidney hypertrophy (3%), three cases of kidney injury (4%), two stage 1 KDIGO and one stage 2 KDIGO. Only one patient benefited from hemodialysis. All patients showing AKI recovered without sequels. The median duration of hospital stays was four days. Seven patients died (14%) including four among the 16 AKI patients. Antivenom has been administered to 41 patients (80%). The comparison between patients without and with AKI did not show any significant difference except gender (p = 10-2).

CONCLUSION

AKI is a common complication of severe snakebite envenomation. Resulting from inflammatory and hemorrhagic disorders, AKI may prove to be a short-term life-threatening factor.

Bedside Coagulation Tests in Diagnosing Venom-Induced Consumption Coagulopathy in Snakebite

Venom-induced consumption coagulopathy is the most important systemic effect of snake envenoming. Coagulation tests are helpful to accurately and promptly diagnose venom-induced consumption coagulopathy and administer antivenom, which is the only specific treatment available. However, bedside clotting tests play a major role in diagnosing coagulopathy in low-income settings, where the majority of snakebites occur. We conducted a literature search in MEDLINE^® from 1946 to 30 November 2019, looking for research articles describing clinical studies on bedside coagulation tests in snakebite patients. Out of 442 articles identified, 147 articles describing bedside clotting assays were included in the review. Three main bedside clotting tests were identified, namely the Lee–White clotting test, 20-min whole blood clotting time and venous clotting time. Although the original Lee–White clotting test has never been validated for snake envenoming, a recently validated version has been used in some South American countries. The 20-min whole blood clotting time test is the most commonly used test in a wide range of settings and for taxonomically diverse snake species. Venous clotting time is almost exclusively used in Thailand. Many validation studies have methodological limitations, including small sample size, lack of case-authentication, the inclusion of a heterogeneous mix of snakebites and inappropriate uses of gold standard tests. The observation times for bedside clotting tests were arbitrary, without proper scientific justification. Future research needs to focus on improving the existing 20-min whole blood clotting test, and also on looking for alternative bedside coagulation tests which are cheap, reliable and quicker.

Clinical assessment and pathophysiology of Bothrops venom-related acute kidney injury: a scoping review

Bothrops are one of the most common medically important snakes found in Latin America. Its venom is predominantly hemotoxic and proteolytic, which means that local lesion (edema and redness) and hemorrhagic symptoms are recurrent in envenoming by this snake. Although hemorrhage is usually the major cause of death, snakebite-related acute kidney injury is another potentially fatal clinical complication that may lead to chronic kidney disease. The present review highlights the main studies on Bothrops venom-related acute kidney injury, including observational, cross-sectional, case-control and cohort human studies available up to December 2019. The following descriptors were used according to Medical Subject Headings (MeSH): on Medline/Pubmed and Google Scholar "acute kidney injury" or "kidney disease" and "Bothrops"; on Lilacs and SciELO "kidney disease" or "acute kidney injury" and "Bothrops". Newcastle-Ottawa quality assessment scale was used to appraise the quality of the cross-sectional and cohort studies included. The selection of more severe patients who looked for health care units and tertiary centers is a risk of bias. Due to the methodological heterogeneity of the studies, a critical analysis of the results was performed based on the hypothesis that the design of the included studies influences the incidence of acute kidney injury. Fifteen human studies (total participants 4624) were included according to stablished criteria. The coagulation abnormalities (hemorrhagic symptoms, abnormal fibrinogen and activated partial thromboplastin time) were associated with acute kidney injury in the most recent studies reported. The findings observed in this review provide up-to-date evidence about the acute kidney injury pathogenesis following Bothrops syndrome. Studies pointed out that coagulation abnormalities comprise the major pathway for acute kidney injury development. This review may improve patient management by primary healthcare providers, allowing earlier diagnosis and treatment of Bothrops venom-related acute kidney injury.

Twelve month prospective study of snakebite in a major teaching hospital in Mandalay, Myanmar; Myanmar Snakebite Project (MSP)

The Myanmar Snakebite Project is an Australian government (Department of Foreign Affairs and Trade) supported foreign aid project in collaboration with the Myanmar government with the aim of improving outcomes for snakebite patients in Myanmar. As part of the project a case record database was established to document prospective cases of snakebite presenting to Mandalay General Hospital, in Upper Myanmar. The study period was 12 months (1-2-2016 to 31-1-2017). Snake identity was based on a mixture of identified dead snakes brought with patients, doctor's clinical opinion and patient identification. 965 patients were enrolled during the 12 month period, of whom 948 were included for analysis. The male: female ratio was 1.58:1. Most cases involved bites to the lower limbs (82.5%) and adults involved in farm work, confirming snakebite as an occupational disease in this community. Motorised transport was by far the most common form of transport to health care and most patients sought care from the health system (87.7%), not traditional healers (11.5%) as their first point of contact. The officially promoted application of a pressure pad, bandage and immobilisation as first aid for snakebite was almost never used, while most patients used some form of tourniquet (92.0%). 85.4% of cases where a snake ID was listed were bitten by Russell's vipers. Russell's viper bites were responsible for all fatalities (9.8% of cases) and all cases of Acute Kidney Injury (AKI). For all cases, clinical features included local swelling (76.5%), local pain (62.6%), AKI (59.8%), incoagulable blood (57.9%), regional lymphadenopathy (39.8%), nausea/vomiting (40.4%), thrombocytopenia (53.6%), abdominal pain (28.8%), shock (11.8%), secondary infection (8.6%), panhypopituitarism (2.1%). AKI required renal replacement therapy (RRT) in 23.9% of cases, all ascribed to Russell's viper bite. Green pit viper bites were the next most common cause of bites (7.6%) and were associated with incoagulable blood (29%) and occasionally shock (5%) and local necrosis (3%), and in one case AKI not requiring RRT. In contrast to Russell's viper bites, green pit viper bite was most likely to occur in the home (49%). Some green pit viper patients were treated with Russell's viper antivenom (15%), presumably because they had incoagulable blood, although this antivenom is not effective against green pit viper envenoming. For the entire patient group, antivenom was given in 80.5% of cases. The most common indications were presence of coagulopathy/non-clotting blood (59.8%), local swelling (47.4%), oliguria/anuria (19.8%), heavy proteinuria (19.4%). A febrile reaction to antivenom was reported in 47.9% of cases, while anaphylaxis, occurred in 7.9% of cases.

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Reports 12 month prospective observational study of snakebite patients at Mandalay General Hosp.

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Snakebite was an occupational disease of farm workers, tourniquets the most common first aid.

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Russell's viper (RV) responsible for most bites, causing coagulopathy, thrombocytopenia, AKI.

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Green pit viper bites were the next most common, potentially causing diagnostic confusion with RV.

Differences between renal effects of venom from two Bothrops jararaca populations from southeastern and southern Brazil

Components from animal venoms may vary according to the snake's age, gender and region of origin. Recently, we performed a proteomic analysis of Bothrops jararaca venom from southern (BjSv) and southeastern (BjSEv) Brazil, showing differences in the venom composition, as well as its biological activity. To continue the study, we report in this short communication the different effects induced by the BjSEv and BjSv on isolated kidney and MDCK renal cells. BjSEv decreased perfusion pressure (PP) and renal vascular resistance (RVR) and increased urinary flow (UF) and glomerular filtration rate (GFR), while BjSv did not alter PP and RVR and reduced UF and GFR. Both types of venom, more expressively BjSEv, reduced %TNa⁺, %TK⁺ and %Cl^-. In MDCK cells, the two types of venom showed cytotoxicity with IC₅₀ of 1.22 μg/mL for BjSv and 1.18 μg/mL for BjSEv and caused different profiles of cell death, with BjSv being more necrotic. In conclusion, we suggest that BjSv is more nephrotoxic than BjSEv.

The Treatment of Snake Bites in a First Aid Setting: A Systematic Review

Background

The worldwide burden of snakebite is high, especially in remote regions with lesser accessibility to professional healthcare. Therefore, adequate first aid for snakebite is of the utmost importance. A wide range of different first aid techniques have been described in literature, and are being used in practice. This systematic review aimed to summarize the best available evidence concerning effective and feasible first aid techniques for snakebite.

Methods

A systematic literature screening, performed independently by two authors in the Cochrane Library, MEDLINE and Embase resulted in 14 studies, fulfilling our predefined selection criteria, concerning first aid techniques for snakebite management. Data was extracted and the body of evidence was appraised according to the GRADE approach.

Principal findings

The pressure immobilization technique was identified as the only evidence-based first aid technique with effectiveness on venom spread. However, additional studies suggest that proper application of this technique is not feasible for laypeople. Evidence concerning other first aid measures, such as the application of a tourniquet, suggests avoiding the use of these techniques.

Conclusions

The practical recommendation for the treatment of snakebite in a first aid setting is to immobilize the victim, while awaiting the emergency services. However, given the low to very low quality of the data collected, high quality randomized controlled trials concerning the efficacy and feasibility of different variations of the pressure immobilization technique are warranted.

The Belgian Red Cross-Flanders develops first aid guidelines that specifically target laypeople. In the context of updating the first aid guidelines for sub-Saharan Africa, we aimed to summarize the best available evidence for the treatment of snakebite, feasible for laypeople. Of the numerous first aid measures supported in literature and used in practice, we could only find evidence concerning effectiveness for the pressure immobilization technique on the spread of snake venom, which involves application of a firm pressure bandage on the bitten limb, together with immobilization of the limb. However, studies concerning its feasibility suggest this technique is difficult for laypeople to apply correctly. Keeping the limb immobilized on the other hand had a beneficial effect on the spread of the venom. However, given the low to very low quality of the evidence, high quality trials concerning the effectiveness and feasibility of different variations of the pressure immobilization technique are needed.

Vulnerabilities in snakebites in Sao Paulo, Brazil

OBJECTIVE

To describe elements of vulnerability of victims of snakebite.

METHODS

This qualitative, descriptive, cross-sectional study had, as theoretical framework, the concept of vulnerability in individual, social, and programmatic dimensions. We interviewed 21 patients admitted into a hospital specialized in the care of accidents caused by venomous animals. The interviews were analyzed according to a discourse analysis technique.

RESULTS

Patients were mainly young men, living in remote countryside areas, where health services frequently have limited resources. We found social and individual conditions of vulnerability, such as precarious schooling, low professional qualification, housing without access to piped water, no sewage treated, and no regular garbage collection, and lack of knowledge on this health problem. Regarding the programmatic dimension, we found limited accessibility to the health services that could affect the prognosis and the frequency of sequelae and deaths.

CONCLUSIONS

Considering such vulnerabilities evoke the need to improve the program for control the Accidents by Venomous Animals and the training of health workers, we highlight the potential use of the concept of vulnerability, which may amplify the understanding and the recommendations for the practice and education related to snakebites.

Secreted phospholipases A2 of snake venoms: effects on the peripheral neuromuscular system with comments on the role of phospholipases A2 in disorders of the CNS and their uses in industry

Neuro- and myotoxicological signs and symptoms are significant clinical features of envenoming snakebites in many parts of the world. The toxins primarily responsible for the neuro and myotoxicity fall into one of two categories--those that bind to and block the post-synaptic acetylcholine receptors (AChR) at the neuromuscular junction and neurotoxic phospholipases A2 (PLAs) that bind to and hydrolyse membrane phospholipids of the motor nerve terminal (and, in most cases, the plasma membrane of skeletal muscle) to cause degeneration of the nerve terminal and skeletal muscle. This review provides an introduction to the biochemical properties of secreted sPLA2s in the venoms of many dangerous snakes and a detailed discussion of their role in the initiation of the neurologically important consequences of snakebite. The rationale behind the experimental studies on the pharmacology and toxicology of the venoms and isolated PLAs in the venoms is discussed, with particular reference to the way these studies allow one to understand the biological basis of the clinical syndrome. The review also introduces the involvement of PLAs in inflammatory and degenerative disorders of the central nervous system (CNS) and their commercial use in the food industry. It concludes with an introduction to the problems associated with the use of antivenoms in the treatment of neuro-myotoxic snakebite and the search for alternative treatments.

Role of the animal model on the pharmacokinetics of equine-derived antivenoms

Antivenom pharmacokinetics has been studied in heterologous models in which the animal species used as immunoglobulin source is different from that used as recipient. In these models, after intravenous administration of antivenom, the plasma concentration of immunoglobulins shows a rapid initial declining-phase followed by a slower terminal-phase, which has been associated with antivenom distribution and elimination, respectively. We have compared pharmacokinetic parameters for equine-derived antivenom in homologous (horse) and heterologous (cow) models. It was found that the maximum concentration is lower in cows than in horses. Additionally, the steady-state distribution volume is higher in cows as compared to horses. On the other hand, models were not different in the time required to reach the maximum concentration, the area under the concentration/time curve, the half-life of decay during the slowest phase, the systemic clearance and the mean residence time. Similar results were obtained in a rabbit model, in which the pharmacokinetics was also affected by passive immunization of rabbits with anti-equine IgG. We conclude that, in addition to other physiological differences (e.g. cardiac frequency, plasmatic volume, glomerular filtration rate, etc.) between animal models, the ability to remove foreign immunoglobulins might influence the way in which the plasma concentration of antivenom decreases over time, thereby distorting the pharmacokinetic predictions based on non-compartmental models.

Evolution of venom antigenaemia and antivenom concentration in patients bitten by snakes in Uruguay

In this work we describe the first study carried out in Uruguay of venom antigenaemia and antivenom concentration in patients bitten by snakes. Between 50 and 70 snake bite accidents per year are caused in Uruguay by 2 species: Rhinocerophis alternatus and Bothropoides pubescens. The patients are treated with a specific polyvalent antivenom. Gaining insight on the evolution of venom antigenaemia and antivenom concentration in patients is important to improve treatment protocols. Blood samples of 29 patients were analysed to determine venom and antivenom concentrations at different times. Venom was detected in 18 of 19 samples before antivenom administration, with a mean concentration of 57 ng/mL. Most of the patients received 4 or 8 vials to neutralize the venom effects. Only one patient needed a total of 16 vials. He showed a severe envenomation and needed supplementary amounts of antivenom after the fifth day of the snake bite accident to reach normal clotting parameters. Antivenom concentrations were determined at 12 h, 24 h and 15 days after antivenom administration. It was found a faster antivenom decrease between 12 and 24 h than to 24 h to 15 days. This was explained by a different clearance mechanism in each period. In the first phase, the cause would be the neutralization of venom present in the blood whereas in the second phase it would be due to unbound antivenom elimination.

The relationship between calcium and the metabolism of plasma membrane phospholipids in hemolysis induced by brown spider venom phospholipase-D toxin

Brown spider venom phospholipase-D belongs to a family of toxins characterized as potent bioactive agents. These toxins have been involved in numerous aspects of cell pathophysiology including inflammatory response, platelet aggregation, endothelial cell hyperactivation, renal disorders, and hemolysis. The molecular mechanism by which these toxins cause hemolysis is under investigation; literature data have suggested that enzyme catalysis is necessary for the biological activities triggered by the toxin. However, the way by which phospholipase-D activity is directly related with human hemolysis has not been determined. To evaluate how brown spider venom phospholipase-D activity causes hemolysis, we examined the impact of recombinant phospholipase-D on human red blood cells. Using six different purified recombinant phospholipase-D molecules obtained from a cDNA venom gland library, we demonstrated that there is a correlation of hemolytic effect and phospholipase-D activity. Studying recombinant phospholipase-D, a potent hemolytic and phospholipase-D recombinant toxin (LiRecDT1), we determined that the toxin degrades synthetic sphingomyelin (SM), lysophosphatidylcholine (LPC), and lyso-platelet-activating factor. Additionally, we determined that the toxin degrades phospholipids in a detergent extract of human erythrocytes, as well as phospholipids from ghosts of human red blood cells. The products of the degradation of synthetic SM and LPC following recombinant phospholipase-D treatments caused hemolysis of human erythrocytes. This hemolysis, dependent on products of metabolism of phospholipids, is also dependent on calcium ion concentration because the percentage of hemolysis increased with an increase in the dose of calcium in the medium. Recombinant phospholipase-D treatment of human erythrocytes stimulated an influx of calcium into the cells that was detected by a calcium-sensitive fluorescent probe (Fluo-4). This calcium influx was shown to be channel-mediated rather than leak-promoted because the influx was inhibited by L-type calcium channel inhibitors but not by a T-type calcium channel blocker, sodium channel inhibitor or a specific inhibitor of calcium activated potassium channels. Finally, this inhibition of hemolysis following recombinant phospholipase-D treatment occurred in a concentration-dependent manner in the presence of L-type calcium channel blockers such as nifedipine and verapamil. The data provided herein, suggest that the brown spider venom phospholipase-D-induced hemolysis of human erythrocytes is dependent on the metabolism of membrane phospholipids, such as SM and LPC, generating bioactive products that stimulate a calcium influx into red blood cells mediated by the L-type channel.

Comparison of Bothropoides jararaca bites with and without envenoming treated at the Vital Brazil Hospital of the Butantan Institute, State of São Paulo, Brazil

INTRODUCTION

This study analyses the cases of all bites (including dry bites) caused by Bothropoides jararaca attended at the Vital Brazil Hospital of the Butantan Institute, State of São Paulo, Brazil.

METHODS

A retrospective study was conducted of patients bitten by Bothropoides jararaca (n=792) from January 1990 to December 2004. The characteristics of the snake specimen, data related to the accident and clinical manifestations on admission were obtained from patient medical records.

RESULTS

The majority of the cases in this study were caused by female and juvenile snakes. No stomach contents were found in 93.4% of the snake specimens after dissection. No statistical difference was observed between the occurrence of dry bites and the maturity or sex of the snake. The median SVL of snakes in mild and moderate cases was 40.5 cm and in severe cases, SVL increased to 99 cm. Necrosis was more common in the digits of the feet and hands (4.8%) compared to the other body regions (1.8%). A significant difference was verified between severity and a time interval greater than six hours from the bite to hospital admission. A significant association was verified between gingival bleeding and abnormal blood coagulability. In accidents caused by adult snakes, necrosis was more frequent (7.2%) compared to accidents caused by juvenile snakes (1%).

CONCLUSIONS

In this work, the association between certain epidemiological data and the evolution of biological parameters in the clinical course of Bothrops sensu latu accidents were highlighted, contributing to the improvement of snake bite assistance.

Compartment syndrome after Bothrops jararaca snakebite: monitoring, treatment, and outcome

OBJECTIVE

To report the outcome of a patient who developed compartment syndrome after Bothrops jararaca snakebite.

CASE REPORT

A 39-year-old male was admitted 5 h after being bitten on the lower right leg. Physical examination revealed tense swelling, ecchymosis, hypoesthesia, and intense local pain that worsened after passive stretching, limited right foot dorsiflexion, and gingival bleeding. The case was classified as moderate/severe and eight vials of bothropic antivenom (AV) were infused 1 h postadmission. The main laboratory findings upon admission were incoagulable blood (incoagulable PT, aPTT, and INR), thrombocytopenia, serum creatine kinase (CK) of 580 U/L (reference value < 170 U/L), and a serum venom level of 33.7 ng/mL (ELISA; cutoff = 2.3 ng/mL). High anterior compartment pressure (60 mmHg) was identified 8 h post bite, with progressively lower pressures after AV administration and limb elevation (36 mmHg; 19 h post bite). However, moderate pain and limited foot dorsiflexion persisted. In addition, there was a progressive increase in serum CK (6,729 U/L; 45 h post bite), as well as marked edema and hemorrhage of the anterior compartment detected by magnetic resonance imaging (MRI) at 48 h post bite. A fasciotomy done after a further increase in intracompartmental pressure (66 mmHg, 57 h post bite) revealed hemorrhage/necrosis of the anterior tibial muscle that subsequently required partial resection. The patient developed a local infection (day 15 post bite) and a permanent fibular palsy.

CONCLUSION

Compartment syndrome is an unusual but severe complication of snakebites. MRI, in conjunction with subfascial pressure measurements, may be useful in the diagnosis of compartment syndrome after snakebites.

Epidemiological, clinical and therapeutic aspects of Bothrops asper bites

Bothrops asper inflicts the majority of snakebites in Central America and in the northern regions of South America, mostly affecting young agricultural workers in rural settings. This species is capable of provoking severe envenomings associated with local and systemic manifestations. The main clinical features are: local edema, ecchymoses, blisters, dermonecrosis, myonecrosis, defibrinogenation, thrombocytopenia, systemic bleeding, hypotension and renal alterations. In addition, soft-tissue infection, acute renal failure, compartmental syndrome, central nervous system hemorrhage and, in pregnant women, abortion, fetal wastage and abruptio placentae have been described as complications. Intravenous administration of antivenom constitutes the mainstay in the therapy. Antivenoms composed of either whole IgG or F(ab')(2) fragments, manufactured in Brazil, Colombia, Costa Rica and Mexico, have been tested in controlled clinical trials, and rational protocols for antivenom administration have been developed. In addition to antivenom therapy, a number of ancillary interventions are recommended in the treatment of B. asper bites.

Cytoskeletal rearrangement and cell death induced by Bothrops alternatus snake venom in cultured Madin–Darby canine kidney cells

Bothrops snake venoms cause renal damage, with renal failure being the main cause of death in humans bitten by these snakes. In this work, we investigated the cytoskeletal rearrangement and cytotoxicity caused by Bothrops alternatus venom in cultured Madin–Darby canine kidney (MDCK) cells. Incubation with venom (10 and 100 µg/mL) significantly (p <0.05) decreased the cellular uptake of neutral red dye after 1 and 3 h. Venom (100 µg/mL) also markedly decreased the transepithelial electrical resistance (RT) across MDCK monolayers. Staining with rhodamine-conjugated phalloidin revealed disarray of the cytoskeleton that involved the stress fibers at the basal cell surface and focal adhesion-associated F-actin in the cell–matrix contact region. Feulgen staining showed a significant decrease in the number of cells undergoing mitosis and an increase in the frequency of altered nuclei. Scanning electron microscopy revealed a decrease in the number of microvilli and the presence of cells with a fusiform format. Flow cytometry with annexin V and propidium iodide showed that cell death occurred by necrosis, with little apoptosis, a conclusion supported by the lack of DNA fragmentation characteristic of apoptosis. Pretreating the cells with catalase significantly attenuated the venom-induced loss of viability, indicating a possible involvement of H2O2 in the cellular damage; less protection was observed with superoxide dismutase or Nω-nitro-l-arginine methyl ester. These results indicate that Bothrops alternatus venom is cytotoxic to cultured MDCK cells, possibly via the action of reactive oxygen species. This cytotoxicity could contribute to nephrotoxicity after envenoming by this species.

Crotaline snake bite in the Ecuadorian Amazon: randomised double blind comparative trial of three South American polyspecific antivenoms

OBJECTIVE

To compare the efficacy and safety of three polyspecific antivenoms for bites by pit vipers.

DESIGN

Randomised double blind comparative trial of three antivenoms.

SETTING

Shell, Pastaza, southeastern Ecuador.

PARTICIPANTS

210 patients with incoagulable blood were recruited from 221 consecutive patients admitted with snake bite between January 1997 and December 2001.

INTERVENTION

One of three antivenoms manufactured in Brazil, Colombia, and Ecuador, chosen for their preclinical potency against Ecuadorian venoms.

MAIN OUTCOME MEASURES

Permanent restoration of blood coagulability after 6 and 24 hours.

RESULTS

The snakes responsible for the bites were identified in 187 cases: 109 patients (58%) were bitten by Bothrops atrox, 68 (36%) by B bilineatus, and 10 (5%) by B taeniatus, B brazili, or Lachesis muta. Eighty seven patients (41%) received Colombian antivenom, 82 (39%) received Brazilian antivenom, but only 41 (20%) received Ecuadorian antivenom because the supply was exhausted. Two patients died, and 10 developed local necrosis. All antivenoms achieved the primary end point of permanently restoring blood coagulability by 6 or 24 hours after the start of treatment in > 40% of patients. Colombian antivenom, however, was the most effective after initial doses of 20 ml (two vials), < 70 ml, and any initial dose at both 6 and 24 hours. An initial dose of 20 ml of Colombian antivenom permanently restored blood coagulability in 64% (46/72) of patients after 6 hours (P = 0.054 compared with the other two antivenoms) and an initial dose of < 70 ml was effective at 6 hours (65%, P = 0.045) and 24 hours (99%, P = 0.06). Early anaphylactoid reactions were common (53%, 73%, and 19%, respectively, for Brazilian, Colombian, and Ecuadorian antivenoms, P < 0.0001) but only three reactions were severe and none was fatal.

CONCLUSIONS

All three antivenoms can be recommended for the treatment of snakebites in this region, though the reactogenicity of Brazilian and Colombian antivenoms is a cause for concern.