Snake Identification Research Articles

Assessment of knowledge about snakebite management amongst healthcare providers in the provincial and two district hospitals in Savannakhet Province, Lao PDR.

ABSTRACTSnakebite is a neglected condition and a common public health problem in Lao People’s Democratic Republic (Lao PDR), with a high incidence of up to 1,105 cases per 100,000 persons per year. Snakebite patients with systemic envenoming do not receive effective treatment at local health facilities. Healthcare providers have only limited knowledge in assessing and providing the correct treatment for venomous snakebites. A cross-sectional study was conducted among 119 healthcare providers in Savannakhet Province, Lao PDR, with respect to their socio-demographic characteristics, knowledge of snake identification, and management of snakebite. Data was analyzed using SPSS. Logistic regression was performed to estimate the odds ratios (OR) and 95% confidence intervals (CI) of adequate knowledge for treating snakebites among the healthcare providers. Among 119 participants, 27.7% and 45.4% had an adequate knowledge of snake identification and management of snakebites, respectively. Approximately 59% could correctly identify symptoms of envenomation, and 19.3% expressed confidence in treating snakebites. Study participants who had received training achieved significantly better snake identification results compared to those without training, with an OR of 2.54 (95% CI: 1.02–6.28). In particular, physicians achieved significantly better results compared to nurses in knowing how to manage snakebites, with an OR of 2.31 (95% CI: 1.04–5.12). Given the level of inadequate knowledge of snakebite management among healthcare providers in the province, more training in snakebite management is needed. University and Health Science Colleges should include snakebite management into the curriculum, to ensure that medical graduates have the appropriate knowledge and skills to treat snakebites.

Safe Handling of Snakes in an ED Setting

A local snake consultation vendor and zoo Herpetologist assisted with development of a process for snake identification and disposal. All snakes have been identified and securely disposed of using the newly implemented process and no safety incidents have been reported. Other emergency department settings may consider developing a standardized process for snake disposal using listed specialized consultants combined with local resources and suppliers to promote employee and patient safety.

Neurotoxicity in Russell’s viper (Daboia russelii) envenoming in Sri Lanka: a clinical and neurophysiological study

Context: Russell’s viper is more medically important than any other Asian snake, due to number of envenoming’s and fatalities. Russell’s viper populations in South India and Sri Lanka (Daboia russelii) cause unique neuromuscular paralysis not seen in other Russell’s vipers. Objective: To investigate the time course and severity of neuromuscular dysfunction in definite Russell’s viper bites, including antivenom response. Methodology: We prospectively enrolled all patients (>16 years) presenting with Russell’s viper bites over 14 months. Cases were confirmed by snake identification and/or enzyme immunoassay. All patients had serial neurological examinations and in some, single fibre electromyography (sfEMG) of the orbicularis oculi was performed. Results: 245 definite Russell’s viper bite patients (median age: 41 years; 171 males) presented a median 2.5 h (interquartile range: 1.75–4.0 h) post-bite. All but one had local envenoming and 199 (78%) had systemic envenoming: coagulopathy in 166 (68%), neurotoxicity in 130 (53%), and oliguria in 19 (8%). Neurotoxicity was characterised by ptosis (100%), blurred vision (93%), and ophthalmoplegia (90%) with weak extraocular movements, strabismus, and diplopia. Neurotoxicity developed within 8 h post-bite in all patients. No bulbar, respiratory or limb muscle weakness occurred. Neurotoxicity was associated with bites by larger snakes (p < 0.0001) and higher peak serum venom concentrations (p = 0.0025). Antivenom immediately decreased unbound venom in blood. Of 52 patients without neurotoxicity when they received antivenom, 31 developed neurotoxicity. sfEMG in 27 patients with neurotoxicity and 23 without had slightly elevated median jitter on day 1 compared to 29 normal subjects but normalised thereafter. Neurological features resolved in 80% of patients by day 3 with ptosis and weak eye movements resolving last. No clinical or neurophysiological abnormality was detected at 6 weeks or 6 months. Conclusion: Sri Lankan Russell’s viper envenoming causes mild neuromuscular dysfunction with no long-term effects. Indian polyvalent antivenom effectively binds free venom in blood but does not reverse neurotoxicity.

Hyperglycemia is a risk factor for high-grade envenomations after European viper bites (Vipera spp.) in children

Context: Hyperglycemia has been described in severe scorpion envenomation, we wanted to analyze if it was applicable to viper bites in children. Aim: To describe clinical, biological, and therapeutic characteristics of 83 children bitten by European viper (Vipera spp.) and to confirm that hyperglycemia is a risk factor for high-grade envenomation. Material and methods: A retrospective study was conducted between 2001 and 2014 in the pediatric emergency department of a tertiary level children’s hospital. Collected data were: age and sex of children; day and time of admission; day, time and circumstances of the accident; snake identification; bite location; envenomation severity; presence of fang marks; prehospital care; laboratory abnormalities, use of specific immunotherapy, associated treatments; length of stay; hospital course. Results: Eighty-three children were included (62 boys, 21 girls). The mean age was 7.4 ± 3.9 years. Bites were most often located on the lower extremities (66%). The classification of envenomation was: 83% low grade (absent or minor envenomation) and 17% high grade (moderate to severe envenomation). All high-grade envenomations received specific immunotherapy (ViperfavTM, (Aventis Pasteur, MSD, Lyon, France). Being bitten on an upper extremity (odds ratio [OR] 51.1 95% class interval [CI] [6.1–424], p < 0.0001), during the afternoon (OR 13.4 95% CI [1.7–107.9], p = 0.015), feeling violent pain (OR 4.2 95% CI [1.1–16.5], p = 0.023), and high initial plasma glucose level (6.5 ± 1.7 mmol/L versus 5.0 ± 0.9 mmol/L, p = 0.027) were associated with a significant risk of high-grade envenomation. Conclusion: We have confirmed a potential link between initial hyperglycemia and the risk of progression to high-grade envenomation as well as its association with other published predictive factors.

Homogeneous fluorescent specific PCR for the authentication of medicinal snakes using cationic conjugated polymers.

A label-free, homogenous and sensitive one-step method for the molecular authentication of medicinal snakes has been developed by combining a rapid PCR technique with water-soluble cationic conjugated polyelectrolytes (CCPs). Three medicinal snake materials (Deinagkistrodon acutus, Zaocys dhumnades and Bungarus multicinctus; a total of 35 specimens) and 48 snake specimens with similar morphologies and textures were clearly distinguished by the naked eye by utilizing a CCP-based assay in a high-throughput manner. The identification of medicinal snakes in patented Chinese drugs was successfully performed using this detection system. In contrast to previous fluorescence-labeled oligonucleotide detection and direct DNA stain hybridization assays, this method does not require designing dye-labeled primers, and unfavorable dimer fluorescence is avoided in this homogenous method.

DNA barcoding and its utility in commonly-used medicinal snakes

Identification accuracy of traditional Chinese medicine is crucial for the traditional Chinese medicine research, production and application. DNA barcoding based on the mitochondrial gene coding for cytochrome c oxidase subunit I (COI), are more and more used for identification of traditional Chinese medicine. Using universal barcoding primers to sequence, we discussed the feasibility of DNA barcoding method for identification commonly-used medicinal snakes (a total of 109 samples belonging to 19 species 15 genera 6 families). The phylogenetic trees using Neighbor-joining were constructed. The results indicated that the mean content of G + C(46.5%) was lower than that of A + T (53.5%). As calculated by Kimera-2-parameter model, the mean intraspecies genetic distance of Trimeresurus albolabris, Ptyas dhumnades and Lycodon rufozonatus was greater than 2%. Further phylogenetic relationship results suggested that identification of one sample of T. albolabris was erroneous. The identification of some samples of P. dhumnades was also not correct, namely originally P. korros was identified as P. dhumnades. Factors influence on intraspecific genetic distance difference of L. rufozonatus need to be studied further. Therefore, DNA barcoding for identification of medicinal snakes is feasible, and greatly complements the morphological classification method. It is necessary to further study in identification of traditional Chinese medicine.

Single-Gene Versus Double-Gene Tree Analyses in Molecular Classification of Saudi Venomous Snakes

Aiming to use DNA sequence for proper identification of venomous snakes in Saudi Arabia, mitochondrial 12S rRNA gene sequences of Bitis arietans, Cerastes cerastes, C. gasperettii, and Echis coloratus were investigated. Concatenated analysis of 16S and 12S rRNA gene sequences (as mosaic) was also performed to validate the usefulness of using more than one gene marker in molecular taxonomy of venomous snakes. DNA extracted from whole blood samples and 12S rRNA was amplified using PCR. Sequences submitted to GenBank were analyzed for similarity using BLAST and aligned using Clustal X followed by manual editing with BioEdit software. Phylogenetic analysis was generated using PAUP version 4, and the evolutionary distance among different groups was calculated using MEGA5 software for both 12S and 16S rRNA genes. Contrary to the morphological classification, phylogenetic analysis revealed that the collected isolates formed three different statistically supported clusters (B. arietans, C. cerastes, and E. coloratus). Although the combined analysis of 16S and 12S rRNA sequences improved the signal, the C. cerastes and C. gasperettii intermixing have not been resolved. Both single and combined genetic distance analyses showed that Echis is more distant from Cerastes than from Bitis. Further studies are mandatory to evaluate other gene markers in molecular classification.

Identification of the Commonest Snake Species Causing Envoniming and Fatality among Snake Bites of Venomous Admission in Dilchora Referral Hospital

Background: Snake bite is a common medical emergency in developing countries. The identification of snake species is important for optimal clinical management, because it allows clinicians to choose the appropriate treatment, anticipate complications, and there fore to improve prognosis. Moreover, helps in selection of specific antivenom and avoids antivenom-induced adverse reactions. The Objective the study is to Identify the commonest Snake species causing envenoming & fatal bites among snake bites of venomous admission in Dilchora referral Hospital from 2006-2011. Methods: The diagnosis was based on the history and account of injury, observation of fang marks, snake identification (when possible) and signs and symptoms of envenoming in patients admitted to orthopedic ward for Supportive therapy without antivenom. Recording of necessary data and analysis were done by the Author. The study was conducted from 2006-2011. Results: During the study period a total of 110(60 Male 54.5% and 40 Female 45.5% ) envenomed patients were admitted in our orthopedic ward making male to female ratio 1.2:1(Table 1). Bites in Under 15 years account for 36(32.7%), in 15-44 years for 69(62.7%), in 45-54 years for 5(4.5%)(Table 1). Bite on the upper limb account for 40(36.4%), on the Lower limb for 66(60%) and on the head & trunk region 4(3.6%)(Table 2). Fatal bite account for 7( 6.4%)(Table 3,4 &5). Known Poisonous snakes caused 86(78.2%) of total envenoming (Table5 and Figure 2). Conclusion: Viper and Puff adder snakes were the commonest causes of fatal bites in our Hospital. Measures to be under taken are recommended. This work is licensed under a Creative Commons Attribution 4.0 International License, which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source (including a link to the formal publication), provide a link to the Creative Commons license, and indicate if changes were made.

Clinical Study of Snakebite Cases Admitted in Dhaka Medical College Hospital

Background: Snake bite is an important health hazard which may lead to fatality in rural areas of Bangladesh. An epidemiological study estimated the incidence of snake bite in Bangladesh about 8,000 per year with 22% mortality. In majority of cases the victims die before entrance to hospital because of their treatment seeking behavior from Ohzas. Present study is to see the clinical profile of snake bite cases admitted in Dhaka Medical College Hospital and also to find out problems in diagnosis and management and outcomes.Methods: Fifty patients of snake bites treated in Dhaka Medical College Hospital, Dhaka, Bangladesh between July 2005 and December 2006 were studied. A questionnaire, containing information on bite, physical examination and identification of snake brought was used.Results: Among the patients venomous snake was 6 (50%) with cobra and 6 (50%) with suspected krait bite. Males were bitten more frequently than females 42(82%) versus 9(18%). Regarding occupation, 28 (56%) was farmer. Majority 37(74%) came from rural areas. Highest number of bite occurred in evening 20(40%). Most snake bite occurred during rural foot walking (30%) followed by sleeping (14%).Total 54% of bite occurred during outdoor activities. Most common site of bite is lower limb 35(70%). Tight tourniquet used in 45(90%) cases and in 8(16%) cases limb was immobilized. Twenty eight (56%) of the patients received treatment from Ohzas. All venomous bites (12) presented with features of neurotoxicity with local envenoming in 6(50%) cases. In 6(50%) cases there were only neuroparalysis. Four (33.34 % of venomous snake) patients required respiratory support and 10(83% of venomous bite) patients required antivenom. There were no anaphylactic reactions and only 2 patients suffered pyrogenic reaction. The outcome was excellent with only one death and only one case of residual effects.Conclusion: To develop an appropriate prevention and control strategy, reliable and timely information has a crucial role. A functional mechanism should be developed to gather information not only about the cases and deaths but other aspects of the snakebite epidemiology.DOI: http://dx.doi.org/10.3329/cmoshmcj.v13i1.19410

Identification and phylogeny of Arabian snakes: Comparison of venom chromatographic profiles versus 16S rRNA gene sequences

Identification of snake species is important for various reasons including the emergency treatment of snake bite victims. We present a simple method for identification of six snake species using the gel filtration chromatographic profiles of their venoms. The venoms of Echis coloratus, Echis pyramidum, Cerastes gasperettii, Bitis arietans, Naja arabica, and Walterinnesia aegyptia were milked, lyophilized, diluted and centrifuged to separate the mucus from the venom. The clear supernatants were filtered and chromatographed on fast protein liquid chromatography (FPLC). We obtained the 16S rRNA gene sequences of the above species and performed phylogenetic analysis using the neighbor-joining method. The chromatograms of venoms from different snake species showed peculiar patterns based on the number and location of peaks. The dendrograms generated from similarity matrix based on the presence/absence of particular chromatographic peaks clearly differentiated Elapids from Viperids. Molecular cladistics using 16S rRNA gene sequences resulted in jumping clades while separating the members of these two families. These findings suggest that chromatographic profiles of snake venoms may provide a simple and reproducible chemical fingerprinting method for quick identification of snake species. However, the validation of this methodology requires further studies on large number of specimens from within and across species.

DNA barcoding using skin exuviates can improve identification and biodiversity studies of snakes

Snakes represent a taxonomically underdeveloped group of animals in India with a lack of experts and incomplete taxonomic descriptions being the main deterrents to advances in this area. Molecular taxonomic approaches using DNA barcoding could aid in snake identification as well as studies of biodiversity. Here a non-invasive sampling method using DNA barcoding is tested using skin exuviates. Taxonomically authenticated samples were collected and tested for validation and comparisons to unknown snake exuviate samples. This approach was also used to construct the first comprehensive study targeting the snake species from Maharashtra state in India. A total of 92 skin exuviate samples were collected and tested for this study. Of these, 81 samples were successfully DNA barcoded and compared with unknown samples for assignment of taxonomic identity. Good quality DNA was obtained irrespective of age and quality of the exuviate material, and all unknown samples were successfully identified. A total of 23 species of snakes were identified, six of which were in the list of Endangered species (Red Data Book). Intra- and inter-specific distance values were also calculated, and these were sufficient to allow discrimination among species and between species without ambiguity in most cases. Two samples were suspected to represent cryptic species based on deep K2P divergence values (>3%), and one sample could be identified to the genus level only. Eleven samples failed to amplify COI sequences, suggesting the need for alternative PCR primer pairs. This study clearly documents how snake skin exuviates can be used for DNA barcoding, estimates of diversity and population genetic structuring in a noninvasive manner.

Discriminative histogram taxonomy features for snake species identification

Abstract Background Incorrect snake identification from the observable visual traits is a major reason for death resulting from snake bites in tropics. So far no automatic classification method has been proposed to distinguish snakes by deciphering the taxonomy features of snake for the two major species of snakes i.e. Elapidae and Viperidae. We identify 38 different taxonomically relevant features to develop the Snake database from 490 sample images of Naja Naja (Spectacled cobra), 193 sample images of Ophiophagus Hannah (King cobra), 88 images of Bungarus caeruleus (Common krait), 304 sample images of Daboia russelii (Russell’s viper), 116 images of Echis carinatus (Saw scaled viper) and 108 images of Hypnale hypnale (Hump Nosed Pit Viper). Results Snake identification performances with 13 different types of classifiers and 12 attribute elevator demonstrate that 15 out of 38 taxonomically relevant features are enough for snake identification. Interestingly, these features were almost equally distributed from the logical grouping of top, side and body views of snake images, and the features from the bottom view of snakes had the least role in the snake identification. Conclusion We find that only few of the taxonomically relevant snake features are useful in the process of snake identification. These discriminant features are essential to improve the accuracy of snake identification and classification. The presented study indicate that automated snake identification is useful for practical applications such as in medical diagnosis, conservation studies and surveys by interdisciplinary practitioners with little expertise in snake taxonomy.

Snake bite poisoning: A neglected life-threatening occupational hazard

Snake bite poisoning: A neglected life-threatening occupational hazard

Snakebite in Australia: a practical approach to diagnosis and treatment

Snakebite is a potential medical emergency and must receive high-priority assessment and treatment, even in patients who initially appear well. Patients should be treated in hospitals with onsite laboratory facilities, appropriate antivenom stocks and a clinician capable of treating complications such as anaphylaxis. All patients with suspected snakebite should be admitted to a suitable clinical unit, such as an emergency short-stay unit, for at least 12 hours after the bite. Serial blood testing (activated partial thromboplastin time, international normalised ratio and creatine kinase level) and neurological examinations should be done for all patients. Most snakebites will not result in significant envenoming and do not require antivenom. Antivenom should be administered as soon as there is evidence of envenoming. Evidence of systemic envenoming includes venom-induced consumption coagulopathy, sudden collapse, myotoxicity, neurotoxicity, thrombotic microangiopathy and renal impairment. Venomous snake groups each cause a characteristic clinical syndrome, which can be used in combination with local geographical distribution information to determine the probable snake involved and appropriate antivenom to use. The Snake Venom Detection Kit may assist in regions where the range of possible snakes is too broad to allow the use of monovalent antivenoms. When the snake identification remains unclear, two monovalent antivenoms (eg, brown snake and tiger snake antivenom) that cover possible snakes, or a polyvalent antivenom, can be used. One vial of the relevant antivenom is sufficient to bind all circulating venom. However, recovery may be delayed as many clinical and laboratory effects of venom are not immediately reversible. For expert advice on envenoming, contact the National Poisons Information Centre on 13 11 26.

Detection of venom–antivenom (VAV) immunocomplexes in vitro as a measure of antivenom efficacy

The measurement of free venom with enzyme immunoassay in serum of patients with snake envenoming is used to confirm snake identification and to determine if sufficient antivenom has been given. Recent studies with Russell's viper (RV; Daboia russelii) envenoming have detected free venom post-antivenom despite recovery of coagulopathy. This raises the question as to whether this assay also measures venom–antivenom (VAV) complexes. In this study we developed an assay to measure VAV complexes and investigate the binding of venom and antivenom in vitro. The assay consisted of rabbit anti-snake venom IgG attached to a microplate which binds the venom component of VAV and anti-horse IgG antibodies conjugated to horseradish peroxidase to detect the antivenom portion of VAV. A known amount of venom or toxin was incubated with increasing antivenom concentrations and VAV was detected as absorbance at 450 nm and plotted against AV concentration. Pseudonaja textilis (brown snake), Notechis scutatus (tiger snake), Oxyuranus scutellatus (taipan), Tropidechis carinatus (rough-scaled snake), Pseudechis porphyriacus (red-bellied black snake) and D. russelii mixtures with appropriate antivenoms were assayed. Measured VAV initially increased with increasing antivenom concentration until it reached a maximum after which the VAV concentration decreased with further increasing antivenom concentrations. The VAV curves for two Australian snake venom–antivenom mixtures, Hoplocephalus stephensii and Ancanthophis antarcticus, had broad VAV peaks with two maxima. Two fractions isolated from N. scutatus venom and Russell's viper factor X activator toxin produced similar VAV curves to their whole venoms. The antivenom concentration for which the maximum VAV occurred was linearly related to the venom concentration, and this slope or ratio was consistent with that used to define the neutralisation units for Australian antivenoms. The maximal VAV point appears to represent the antivenom concentration where every venom molecule (toxin) is attached to at least one antivenom molecule (antibody) on average and may be a useful measure of antivenom efficacy. In vivo this would mean that for a defined antivenom concentration, venom components will be eliminated and are trapped in the central compartment.

Point-of-care derived INR does not reliably detect significant coagulopathy following Australian snakebite

Point-of-care international normalised ratio (INR) has been suggested as a way to screen for venom-induced consumption coagulopathy following snakebite, but has not been validated for this. This study aimed to assess the diagnostic reliability of point-of-care INR for venom-induced consumption coagulopathy. This was a prospective study of snakebite patients recruited between January 2011 and May 2012 where a point-of-care INR was done and compared to an INR done on a laboratory coagulation analyser, as part of a quality assurance exercise. Data was obtained for each patient, including demographics, information on the snake bite, the point-of-care INR results and any laboratory derived coagulation studies. Snake identification was confirmed by expert identification or venom specific enzyme immunoassay. There were 15 patients with a median age of 29 years (2 to 68 y) and 13 were male. Four of the 7 patients with venom-induced consumption coagulopathy had an abnormal point-of-care INR (3 false negatives) and 1 of the 7 non-envenomed patients had an abnormal point-of-care INR (1 false positive). The patient with a falsely elevated point-of-care INR was given antivenom prior to formal coagulation studies. The point-of-care INR was also negative in the patient with an anticoagulant coagulopathy. The study shows that point-of-care INR testing devices should not be used in suspected snakebite cases in Australia to diagnose venom-induced consumption coagulopathy.

Hump-nosed pit viper (Hypnale hypnale) envenoming causes mild coagulopathy with incomplete clotting factor consumption

Context. Limited information exists on the coagulopathy caused by hump-nosed pit viper (Hypnale hypnale) envenoming. Objectives. This study aimed to characterise the coagulopathy in hump-nosed pit viper bites by measuring laboratory clotting times and factor studies. Materials and methods. Cases of hump-nosed pit viper envenoming were included from a prospective cohort study of Sri Lankan snake-bite patients. Patient age, sex, snake identification, time of bite and clinical effects were recorded. Patients did not receive anti-venom because no specific anti-venom to hump-nosed vipers exists. All patients received supportive care and serial 20-min whole blood clotting tests (WBCT20). The prothrombin time (PT), international normalised ratio (INR), activated partial thromboplastin time (aPTT), coagulation factors I, II, V, VII, VIII, IX and X, von Willebrand factor (vWF) antigen and D-Dimer concentrations were measured. The median of highest or lowest test result for each patient was reported with interquartile range (IQR). Results. There were 80 hump-nosed pit viper bites, median age was 37 years (IQR: 26–51 years) and 48 were male. The WBCT20 was positive in one patient. The median highest INR was 1.9 (1.5–2.2; Range: 1.3 to > 12) and median highest aPTT was 54 s (46–72 s; Range: 35–170 s). There was low fibrinogen [median: 1.3 g/L;1, –1.8 g/L; Range: < 0.2–2.9], low factor VIII levels [median: 23%; 16–37%] and low factor V levels [median: 43%; 23–74%]. D-Dimer concentrations [median: 3.4 mg/L; 2–7.4 mg/L] were slightly elevated. Factors II, VII and X and vWF antigen concentrations were normal. Discussion and Conclusions. Hump-nosed pit viper bites result in a mild coagulopathy which is usually not detected by a WBCT20. It is characterised by mild elevation of INR, low fibrinogen and Factors V and VIII which may be consistent with the venom containing a thrombin-like enzyme.

Tiger snake (Notechis spp) envenoming: Australian Snakebite Project (ASP‐13)

OBJECTIVES: To describe the clinical syndrome associated with definite tiger snake (Notechis spp) envenoming and to examine the ability of tiger snake antivenom (TSAV) to bind free venom in vivo. DESIGN, SETTING AND PARTICIPANTS: We conducted a prospective cohort study within the Australian Snakebite Project, reviewing all definite tiger snake envenoming cases between October 2004 and June 2011. Definite cases were identified by venom-specific enzyme immunoassay or expert snake identification. MAIN OUTCOME MEASURES: Clinical effects of tiger snake envenoming; peak venom concentrations; number of vials of antivenom administered. RESULTS: Fifty-six definite tiger snake envenomings were identified. Clinical effects included venom-induced consumption coagulopathy (VICC) (n = 53), systemic symptoms (n = 45), myotoxicity (n = 11) and neurotoxicity (n = 17). Thrombotic microangiopathy occurred in three patients, all of whom developed acute renal failure. There were no deaths. A bite-site snake venom detection kit test was done in 44 patients, but was positive for tiger snake in only 33 cases. Fifty-three patients received TSAV and eight of these patients had immediate hypersensitivity reactions, severe enough in one case to satisfy diagnostic criteria for severe anaphylaxis. The median peak venom concentration in 50 patients with pretreatment blood samples available was 3.2 ng/mL (interquartile range [IQR], 1-12 ng/mL; range 0.17-152 ng/mL). In 49 patients with post-treatment blood samples available, no venom was detected in serum after the first antivenom dose. Ten patients were given 1 vial of TSAV; the median dose was 2 vials (range, 1-4 vials). Pretreatment serum venom concentrations did not vary significantly between patients given 1 vial of TSAV and those given 2 or more vials. CONCLUSION: Tiger snake envenoming causes VICC, systemic symptoms, neurotoxicity and myotoxicity. One vial of TSAV, the dose originally recommended when the antivenom was first made available, appears to be sufficient to bind all circulating venom. Language: en

Clinical Effects and Antivenom Dosing in Brown Snake (Pseudonaja spp.) Envenoming — Australian Snakebite Project (ASP-14)

BackgroundSnakebite is a global health issue and treatment with antivenom continues to be problematic. Brown snakes (genus Pseudonaja) are the most medically important group of Australian snakes and there is controversy over the dose of brown snake antivenom. We aimed to investigate the clinical and laboratory features of definite brown snake (Pseudonaja spp.) envenoming, and determine the dose of antivenom required.Methods and FindingThis was a prospective observational study of definite brown snake envenoming from the Australian Snakebite Project (ASP) based on snake identification or specific enzyme immunoassay for Pseudonaja venom. From January 2004 to January 2012 there were 149 definite brown snake bites [median age 42y (2–81y); 100 males]. Systemic envenoming occurred in 136 (88%) cases. All envenomed patients developed venom induced consumption coagulopathy (VICC), with complete VICC in 109 (80%) and partial VICC in 27 (20%). Systemic symptoms occurred in 61 (45%) and mild neurotoxicity in 2 (1%). Myotoxicity did not occur. Severe envenoming occurred in 51 patients (38%) and was characterised by collapse or hypotension (37), thrombotic microangiopathy (15), major haemorrhage (5), cardiac arrest (7) and death (6). The median peak venom concentration in 118 envenomed patients was 1.6 ng/mL (Range: 0.15–210 ng/mL). The median initial antivenom dose was 2 vials (Range: 1–40) in 128 patients receiving antivenom. There was no difference in INR recovery or clinical outcome between patients receiving one or more than one vial of antivenom. Free venom was not detected in 112/115 patients post-antivenom with only low concentrations (0.4 to 0.9 ng/ml) in three patients.ConclusionsEnvenoming by brown snakes causes VICC and over a third of patients had serious complications including major haemorrhage, collapse and microangiopathy. The results of this study support accumulating evidence that giving more than one vial of antivenom is unnecessary in brown snake envenoming.

Risk Factors for High-Grade Envenomations After French Viper Bites in Children

Viper bites and subsequent evolution to severe envenomations are more frequent in children. The aims of this study were to describe the clinical, biological, and therapeutic characteristics of children bitten by vipers in France and to identify risk factors associated with severe envenomations. A retrospective study was conducted between 2001 and 2009 in the pediatric emergency department of a tertiary-level children hospital. Collected data were age and sex of children; day and time of admission; day, time, and circumstances of the accident; snake identification; bite location; envenomation severity; presence of fang marks; prehospital care; use of specific immunotherapy and associated treatments; length of stay; and hospital course. Fifty-eight children were included (43 boys, 15 girls). The mean age was 7.8 ± 4.1 years. Bites were most often located on the lower extremities (77%). The classification of envenomation was: 83% low grade (absence or minor envenomation) and 17% high-grade (moderate to severe envenomations). All high-grade envenomations received specific immunotherapy (Viperfav). Being bitten on an upper extremity (P < 0.001), during the afternoon (P = 0.025), feeling violent pain (P = 0.037), and high initial glucose level (P = 0.016) were associated with a significant risk of high-grade envenomation. In the multivariate analysis, 3 factors remained significant: upper-extremity location (relative risk [RR], 60.5 [3.5-1040]; P = 0.005), immediate violent pain (RR, 21.5 [1.3-364.5]; P = 0.03), and female sex (RR, 17.5 [0.9-320.3]; P = 0.053). A certain number of criteria seem related to more significant risk of progression to high-grade envenomation. Bites to the upper extremities should be carefully observed because of the risk of evolution to a high-grade envenomation.