Management of snakebites in France

Envenomation by Vipera aspis in Piedmont (Italy): A report of three cases, including one case with neurological symptoms

This report describes three cases of human envenomation by the asp viper (Vipera aspis) in Piedmont, north-west Italy. A woman was bitten on the ankle while she was hiking and two herpetologists received bites on the hand while they were manipulating the animals. In the first case, the victim presented severe systemic symptoms (abdominal pain, vomiting, diarrhea) that required treatment with two vials of antivenom and hospitalization for one week. In the second case, the patient manifested neurological symptoms (blepharoptosis, ophtalmoplegia); he was treated with antivenom and discharged after five days. In the third case, the patient was bitten by a juvenile viper and showed only local symptoms (edema and bruising). All patients reported prolonged functional impairment after discharge from hospital. Although uncommon, envenomation by Vipera aspis can cause severe consequences that require immediate management and antivenom administration. These cases highlight the importance of obtaining better knowledge of the intraspecific variability of venoms and its clinical significance, as well as of the factors that determine the severity of snakebite injuries.

What drives the risk of being bitten by a viper? A fine spatial scale study in western France

Previous studies on viper bites in France have focused on clinical consequences of envenomation, efficacy of antivenom and epidemiology of bites. Herein, we wanted to clarify temporal and spatial patterns in bite incidence using a fine spatial scale (municipality level). We focused on viper bites recorded over the last 10 years in 4 regions of western France. We addressed the determinants of bite occurrence and number of bites considering the following variables: predicted probability of viper presence, species (V. aspis or V. berus), climatic data, tourism function rate, soil transformation and landscape use. 703 bite cases were retained with significant disparities between areas. Bites occurred either during a garden-related activity (339 cases, 51.2%) or during an activity in the countryside (300 cases, 45.3%). The probability of presence of a viper at the municipality level positively influenced the risk of being bitten (multiplied by 3 for a variation in probability of 0.25 from 0.5) but varied between species (lower in V. berus than V. aspis). Artificial land development had a positive effect on bite risks. Finally, a tourism function rate above 50 beds/100 inhabitants was strongly associated with an increase in the risk of occurrence and frequency of bites. Overall, viper bites recorded in our study were concentrated on the south coastline of Pays de la Loire region. The coastal towns are significant areas of tourist attraction and are located close to preserved semi-natural landscapes that provide favorable habitats for vipers. This convergence may favor human/wildlife encounters.

Neurotoxicity and Other Clinical Manifestations of a Common European Adder (Vipera berus) Bite in Romania

Most cases of envenomation by common European vipers (Vipera berus) have not been reported to have neurotoxic manifestations. However, these manifestations have been demonstrated in some cases of envenomation by subspecies of V. berus, found in the Carpathian Basin region of south-eastern Europe. Here, we report the case of a 5-year-old girl from the south of Romania who presented symptoms of neurotoxicity, as well as other systemic and local symptoms, after being bitten by an adder of the V. berus subspecies. Treatment consisted of monovalent antivenom, a corticosteroid, and prophylactic enoxaparin. Neurotoxic manifestations of envenomation as well as other local and systemic symptoms improved within 5 days of treatment. The presented case shows that venom from V. berus subspecies found in the Carpathian Basin can have neurotoxic effects. This case also confirmed the efficacy of monospecific antivenom treatment in bringing about rapid and complete remission, following envenomation.

Snake Envenomation

SNAKE ENVENOMATION REPRESENTS AN IMPORTANT HEALTH PROBLEM IN much of the world. In 2009, it was recognized by the World Health Organization (WHO) as a neglected tropical disease, and in 2017, it was elevated into Category A of the Neglected Tropical Diseases list, further expanding access to funding for research and antivenoms. However, snake envenomation occurs in both tropical and temperate climates and on all continents except Antarctica. Worldwide, the estimated number of annual deaths due to snake envenomation (80,000 to 130,000) is similar to the estimate for drug-resistant tuberculosis and for multiple myeloma.^, In countries with adequate resources, deaths are infrequent (e.g., <6 deaths per year in the United States, despite the occurrence of 7000 to 8000 bites), but in countries without adequate resources, deaths may number in the tens of thousands. Venomous snakes kept as pets are not rare, and physicians anywhere might be called on to manage envenomation by a nonnative snake. Important advances have occurred in our understanding of the biology of venom and the management of snake envenomation since this topic was last addressed in the Journal two decades ago. For the general provider, it is important to understand the spectrum of snake envenomation effects and approaches to management and to obtain specific guidance, when needed.

First step in assessment of VipGrade®, a computerized clinical decision system to assess Vipera envenomation grading: a single-center interrater reliability study

METHODS

We conducted a retrospective review of Vipera spp. snakebite cases registered by the PCC of Bordeaux, France, between January 1, 2018, and December 31, 2020, evaluating the agreement between VipGrade^® assessments, toxicologists' assessments, and current guidelines.

RESULTS

133 patients with Vipera aspis snakebites were included. There was 100% agreement in severity grading by PCC guidelines and VipGrade^®. However, grading by toxicologists and VipGrade^® diverged in 19 cases (85% agreement; κ = 0.80; 95% CI: 0.71 to 0.87).

CONCLUSIONS

The VipGrade^® tool's grading reflects current PCC guidelines, which are authoritative in France, and may allow for a more rapid and standardized determination of management and follow-up of viper-bitten patients. It should be noted, however, that the more complex and dynamic aspects of management are not included in VipGrade^®. Its purpose is to supplement, not replace, the advice of the PCC's clinical toxicologists, and this advice should be sought whenever a viper bite is encountered in clinical practice.

Acute Exposure to European Viper Bite in Children: Advocating for a Pediatric Approach

Viper bite is an uncommon but serious cause of envenoming in Europe, especially in children. Our study aim is to better describe and analyze the clinical course and treatment of viper bite envenoming in a pediatric population. We retrospectively reviewed 24 cases of pediatric viper bites that were admitted to the Pediatric Emergency Department and the Pediatric Intensive Care Unit of the Bambino Gesù Children Hospital in Rome between 2000 and 2020. Epidemiological characteristics of the children, localization of the bite, clinical and laboratory findings, and treatment approaches were evaluated. The median age of the patients was 4.2 years, with male predominance. Most cases of viper bite occurred in the late summer. Most patients required admission to the ward for prolonged observation. The most common presenting signs were pain, local oedema, and swelling. Patients with a high severity score also had a significantly higher white blood cell count and an increase of INR, LDH, and CRP levels. No fatality was reported. Viper bite envenomation is a rare pediatric medical emergency in Italy but may sometimes be severe. A new pediatric severity score may be implemented in the screening of children with viper bites to favor a selective and prompt administration of antivenom.

Snake bites by European vipers in Mainland France in 2017-2018: comparison of two antivenoms Viperfav® and Viperatab®

Context: Today, immunotherapy with Fab or F(ab')₂ fragments is considered as a gold standard treatment for patients bitten by vipers. We compared the efficiency of two antivenoms, Viperfav^® and Viperatab^®, in mainland France in 2017-2018 with data provided by the French poison control centre (PCC).Methods: Patients with a moderate (2a and 2b) or severe (3) envenomation after a European viper bite and treated with immunotherapy were included and the markers chosen were the risk of post-antivenom treatment worsening, duration of hospital stay and persistent functional discomfort on day 15. Statistical studies were based on multivariate data analysis.Results: Two hundred and ninety-seven cases were recorded. One hundred and eighty-two (61.3%) patients received Viperfav^® and 115 (38.7%) received Viperatab^®. Compared to Viperfav^®, use of Viperatab^® significantly increased the risk of post-antivenom treatment worsening (OR* 12.05; 95%CI [3.11; 46.70]; p < .001). No significant difference between these antivenoms was recorded with respect to the duration of hospital stay and persistent functional discomfort on day 15. Viperfav^® and Viperatab^® have a similar tolerance (p > .21). Otherwise, duration of hospitalisation was significantly increased by a delay of immunotherapy infusion of more than 12 h (OR 2.70; 95%CI [1.45-5.06]; p = .002) or a preventive administration of LMWH (OR 6.55; 95%CI [1.58-27.13]; p=.02).Discussion: While Viperfav^® and Viperatab^® have a similar tolerance, our data show that Viperatab^® was associated with a higher risk of post-antivenom treatment worsening compared to Viperfav^®. Furthermore, this study confirms that the antivenom should be used as soon as possible. Indeed, patients receiving the immunotherapy infusion from the grade 2b presented significantly more frequent exacerbated symptoms (OR 3.99; 95%CI [1.16-13.73]; p=.028) after the antivenom infusion compared to grade 2a group.Conclusions: Whereas no significant difference between these antivenoms was recorded with respect to the duration of hospital stay and persistent functional discomfort on day 15, use of Viperatab^®, compared to Viperfav^®, significantly increased the risk of post-antivenom treatment worsening (OR* 12.05; 95%CI [3.11; 46.70]; p < .001). Taken together, these data show that Viperfav^® is the treatment of choice for the management of snake bites in France.

Variability in venom composition of European viper subspecies limits the cross-effectiveness of antivenoms

Medically relevant cases of snakebite in Europe are predominately caused by European vipers of the genus Vipera. Systemic envenoming by European vipers can cause severe pathology in humans and different clinical manifestations are associated with different members of this genus. The most representative vipers in Europe are V. aspis and V. berus and neurological symptoms have been reported in humans envenomed by the former but not by the latter species. In this study we determined the toxicological profile of V. aspis and V. berus venoms in vivo in mice and we tested the effectiveness of two antivenoms, commonly used as antidotes, in counteracting the specific activities of the two venoms. We found that V. aspis, but not V. berus, is neurotoxic and that this effect is due to the degeneration of peripheral nerve terminals at the NMJ and is not neutralized by the two tested antisera. Differently, V. berus causes a haemorrhagic effect, which is efficiently contrasted by the same antivenoms. These results indicate that the effectiveness of different antisera is strongly influenced by the variable composition of the venoms and reinforce the arguments supporting the use polyvalent antivenoms.

A Single Dose of Viperfav(TM) May Be Inadequate for Vipera ammodytes Snake Bite: A Case Report and Pharmacokinetic Evaluation

Viperfav^TM is a commercial F(ab’)₂ antivenom prepared against European vipers venom. It is safe and effective for treating envenomation caused by Vipera aspis and Vipera berus. Therapeutic efficacy for treating Vipera ammodytes ammodytes (V. a. ammodytes) envenoming has not been yet described, although protective efficacy has been demonstrated in preclinical studies. We report on a 32-year-old man bitten by V. a. ammodytes who was treated with Viperfav™. Viperfav™ promptly reduced local extension and improved systemic pathological signs, but 24 h after the incident a recurrence of thrombocytopenia occurred despite a favorable pharmacokinetic profile with systemic clearance (1.64 (mL·h⁻¹)·kg⁻¹) and elimination half-life (97 h) among the highest ever reported. The recommended dose of Viperfav™ for V. aspis and V. berus bites may be inadequate for serious V. a. ammodytes envenomations. Following V. a. ammodytes bite, serial blood counts and coagulation profiles should be performed to help guide Viperfav™ treatment, along with supplemental administration as indicated.

Bilateral Pulmonary Embolism Following a Viper Envenomation in France: A Case Report and Review

Complications following snake bites are not common in France. We report the case of a bilateral pulmonary embolism following a viper envenomation in France.A healthy 72-year-old female presented with a lower limb hematoma following a viper bite. She was admitted at the hospital 2 days later and received low-molecular-weight heparin because of bed rest. Seven days later, she complained of thoracic pain and respiratory failure, and a bilateral pulmonary was diagnosed, without biological sign of neither disseminated intravascular coagulation nor coagulation trouble. Repeated lower limbs Doppler ultrasound were normal.This case is particularly interesting because it is only the 7th reported case of pulmonary embolism following a snake envenomation; moreover, it happened in France where poisonous snakes are very rare.Several hypotheses have been made to explain this late localized coagulopathy: an increased level of unstable fibrin produced by thrombin-like glycoproteins from the venom is one of them.

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 (Viperfav(TM), (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.

European viper envenomation recorded by French poison control centers: A clinical assessment and management study

INTRODUCTION

Immunotherapy is the gold standard treatment for patients bitten by European vipers in France; it significantly decreases morbidity, frequency and severity of complications and length of stay. A national prospective study was performed by all Poison Control Centers (PCC) to validate the emergency protocol for viper envenomations.

METHODS

This prospective study included all cases of viper bites in France, treated or not with Viperfav(®) in 2013.

RESULTS

In 2013, 277 cases of viper bites were collected: ratio M/F 2.1; mean aged 43 years (<15 years 25% 15-65 63% > 65 12%). The final severity was divided into 68 grades 0, 58 grades I, 62 grades IIA, 71 grades IIB and 18 grades III. One death was reported. Five patients had neurological signs. For the 114 patients who received Viperfav(®), all systemic signs disappeared in 5 h and in 24 h for biological and neurological signs. No severe anaphylactic reaction with Viperfav(®) was reported. Late Viperfav(®) administration increased the risk of functional impairment 15 days after the bite (OR = 3.21 p = 0.043). The administration of Low Molecular Weight Heparin (LMWH) increased the frequency of functional impairment to 15 days after the bite (OR = 6.38 p = 0.064), although Viperfav(®) was given in the first 18 h.

DISCUSSION

This study confirms the efficiency, safety and recommendation of an early administration of a single dose of Viperfav(®), LMWH should not be used. It also shows the extension of neurotoxic venom of vipers in France.

Non-native (exotic) snake envenomations in the U.S., 2005-2011

Non-native (exotic) snakes are a problematic source of envenomation worldwide. This manuscript describes the current demographics, outcomes and challenges of non-native snakebites in the United States (U.S.). We performed a retrospective case series of the National Poison Data System (NPDS) database between 2005 and 2011. There were 258 human exposures involving at least 61 unique exotic venomous species (average = 37 per year; range = 33-40). Males comprised 79% and females 21%. The average age was 33 years with 16% less than 20 years old. 70% of bites occurred in a private residence and 86% were treated at a healthcare facility. 35% of cases received antivenom and 10% were given antibiotics. This study is compared to our previous study (1994-2004) in which there was a substantial coding error rate. Software modifications significantly reduced coding errors. Identification and acquisition of appropriate antivenoms pose a number of logistical difficulties in the management of these envenomations. In the U.S., poison centers have valuable systems and clinical roles in the provision of expert consultation and in the management of these cases.

Neurotoxicity of European viperids in Italy: Pavia Poison Control Centre case series 2001-2011

CONTEXT

Some clinical aspects about neurotoxicity after snakebites by European viper species remain to be elucidated.

OBJECTIVE

This observational case series aims to analyze neurological manifestations due to viper envenomation in Italy in order to describe the characteristic of neurotoxicity and to evaluate the clinical response to the antidotic treatment, the outcome, and the influence of individual variability in determining the appearance of neurotoxic effects.

MATERIALS AND METHODS

All cases of snakebite referred to Pavia Poison Centre (PPC) presenting peripheral neurotoxic effects from 2001 to 2011 were included. Cases were assessed for time from bite to PPC evaluation, Grade Severity Score (GSS), onset/duration of clinical manifestations, severity/time course of local, non-neurological and neurological effects, and antidotic treatment.

RESULTS

Twenty-four were included (age, 3-75 years) and represented on average of 2.2 cases/year (about 5% of total envenomed patients). The mean interval time of PPC evaluation from snakebite was 10.80 ± 19.93 hours. GSS at ED-admission was 0 (1 case), 1 (10 cases), and 2 (13 cases). All patients showed local signs: 41.6%, minor; 58.4%, extensive swelling and necrosis. The main systemic non-neurological effects were as follows: vomiting (86.7%), diarrhea (66.7%), abdominal discomfort (53.3%), and hypotension (20%). Neurotoxic effects were accommodation troubles and diplopia (100%), ptosis (91.7%), ophtalmoplegia (58.3%), dysphagia (20.8%), drowsiness (16.6%), cranial muscle weakness (12.5%), and dyspnea (4.2%). Neurotoxicity was the unique systemic manifestation in 9 cases; in 4 cases, they were associated with only mild local swelling. In 10 patients the onset of neurotoxic effects followed the resolution of systemic non-neurological effects. Antidote was intravenously administered in 19 (79.2%) patients. The mean duration of manifestations in untreated versus treated groups was 53.5 ± 62.91 versus 41.75 ± 21.18 hours (p = 0.68, local effects) and 9.77 ± 3.29 versus 8.25 ± 12.23 hours (p = 0.1, systemic non-neurological effects) and 43.4 ± 14.69 versus 26.58 ± 20.62 hours (p = 0.03, neurotoxic effects).

CONCLUSIONS

Neurotoxicity may appear late (11 hours after the bite in 58.3% of cases), in contrast with the data reported in medical literature. Neurotoxic effects have been reversible in all cases and may be the unique systemic manifestation of envenomation. Neurotoxic effects are shorter in treated group. The antidotic treatment of patients considered as GSS 2 only for neurotoxic effects (with mild local effects) may not be necessary. Variable factors such as different amount of venom injected, concentration of PLA2 component, and individual susceptibility may explain the less percentage of patients presenting neurotoxic effects.

Exotic snake bites in the Czech Republic--Epidemiological and clinical aspects during 15-year period (1999-2013)

Only one natural venomous snake-the adder viper-lives in the central European region and its bite is usually associated only with mild course of envenoming. Cases of envenoming caused by exotic snakes among their breeders are clinically more important.

OBJECTIVE

The aim of this study was to analyze the epidemiological and clinical aspects of registered venomous bites caused by exotic snakes in the Czech Republic over a period of 15 years (1999-2013).

MATERIALS AND METHODS

This is an observational case series. Data have been collected retrospectively from a database and medical charts of the Toxinology Center belonging to the General University Hospital in Prague.

RESULTS

In total, 87 cases of exotic snakebites caused by 34 venomous snake species were registered during the study period, coming from 18 genera of Elapinae, Viperinae, and Crotalinae subfamilies. In the cohort, 29 patients (33.3%) developed systemic envenoming and 17 (19.5%) were treated with antivenom. Ten cases of envenoming (11.5%) were considered as potentially life threatening. No patient died due to envenoming caused by exotic snake bites during the study period. Four illustrative cases of envenoming (Echis pyramidum, Dendroaspis polylepis, Protobothrops mangshanensis, and Proatheris superciliaris) are described in detail.

CONCLUSION

Bites caused by exotic snakes resulted in serious and life-threatening envenomings in some patients. Early transfer to the Center, antivenom administration, and support of failing organ functions contributed to favorable outcome of victims.