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

Self-reported health effects after one year from a viper bite: A prospective study from France

In France, the summer period (from mid-April to mid-September) is particularly prone to viper envenomations by the two most common species, Vipera aspis and Vipera berus, which represents a significant public health issue. Although mortality is extremely low and systemic signs are rare, some patients experience long-term functional sequelae, highlighting the need for further exploration of the prolonged effects of snakebites. We conducted an observational study of viper bite cases in France collected during routine follow-ups by four Poison Control Centers. Patients were followed up by toxicologists using a standardized survey to assess recovery time and health indicators. Over two years, 170 patients were included, with a sex ratio of 1.54 (103 males vs. 67 females) and a median age of 46.2 years. The median recovery time was 21 days, with 84% of patients healed by 6 months, and recovery probabilities of 0.47, 0.65, and 0.86 at 14, 30, and 180 days, respectively. Parameters associated with delayed recovery were severe bite, lower limb bite, female gender, inappropriate treatment, and time to hospital admission. Age and time to administration of antivenom had no effect. One month after the bite, 12.8% of patients avoided the activity during which they were bitten, 5.6% frequently thought about the bite, and 22.3% were afraid of snakes; these figures increased to 14.6%, 4.5%, and 38.2%, respectively, after one year. Other factors than severity of envenomation should be taken into account in the long-term prognostic assessment of patients. Psychological impacts, though not clinically classified as traumatic events, suggest a need to consider mental health in recovery. Prompt administration of antivenom and compliance with recommended management remain key elements of effective care. It is important to re-evaluate the need for patient follow-up in the light of the factors identified as affecting the early favourable evolution of symptoms.

Vipera Snakebite in Children: A Focus on Europe

Although there are over 5 million cases of snakebites each year, up-to-date data on epidemiology and management in European children are lacking in literature. Snakebite envenoming is a rare but potentially life-threatening event, and children are more susceptible due to their lower weight-to-venom ratio. Symptoms of viper envenomation in children are mainly local, but the lymphatic and blood diffusion of the venom may cause systemic symptoms, mainly hemotoxic and cytotoxic symptoms. Immunotherapy with anti-viper serums is the cornerstone of treatment for viper bites, while the use of antibiotics, steroids and analgesics is still unclear and unstandardized. Recently, efforts have been made to improve the pediatric approach to viper envenomation in European children. Several pediatric case reports in children were reported in literature, and a pediatric grading severity score and electronic clinical tool (VipGrade®) were created to better manage this issue. However, larger studies are needed to validate these pediatric tools. This narrative review focuses on the clinical characteristics and management of European snake envenomation in children.

Intraspecific venom variation in the Iberian asp viper (Vipera aspis zinnikeri) across natural and intensive agricultural habitats

Snake venom composition varies at different levels. To date, comparative venom studies have seldom taken into account the role of habitat type in the occurrence of snake venom variation. Here we investigated the presence of venom variation across different populations of the Iberian asp viper (Vipera aspis zinnikeri) inhabiting two contrasting habitats: natural vs. intensive agricultural. We used shotgun proteomics to describe the protein composition of the venoms of six adults from two distinct localities. Furthermore, to test whether local conditions and habitat can alter venom composition in this taxon, we compared the SDS-PAGE profiles of 40 adult venoms from six populations, three in natural habitats and three in intensive agricultural environments. The venoms were composed of 21 toxin families, of which five (CTL, PLA2, VEGF, svSP, and svMP) comprised 69-82 % of each proteome. The relative abundances of toxin families varied considerably at inter- and intra-population levels. Linear regression performed on non-metric multidimensional scaling values showed a significant effect of locality of origin and habitat type on the differences detected between individual SDS-PAGE venom profiles. Our results suggest the presence of regional variation in V. a. zinnikeri venom, potentially reinforcing the role of local pressures in shaping snake venom composition. SIGNIFICANCE: This work provides the first proteomic characterization of the venom of the Iberian asp viper, Vipera aspis zinnikeri, obtained by means of shotgun proteomics. The statistical analysis of 40 individual SDS-PAGE venom profiles highlights that venom variation in this taxon can be associated with geographical origin and habitat type of the area where each viper was collected. Our results suggest the presence of regional variation in V. a. zinnikeri venom, reinforcing the role that local pressures may play as drivers of snake venom variation.

Venom-induced myocarditis: An unusual case attributable to Vipera aspis bite

Venomous bites are medical emergencies that may result in life-threatening clinical effects. Cardiovascular complications are uncommon but they can be dangerous if not early detected and treated. Cerebral and myocardial infarction are described; myocarditis as consequence of viper envenomation in humans are very rare, almost anedoctal. We present the case of a 33-year-old man, working as keeper in a reptile zoo, who arrived after a viper bite of the Vipera aspis species, on the left wrist. The patient presented with clouded sensorium, edema of the lips and tongue, rapidly worsened with angioedema, and the need for oro-tracheal intubation; severe thrombocytopenia and anemia were treated with transfusions of platelet, plasma and red blood cells. The left hand and arm worsened, with compartment syndrome, treated with surgical fasciotomy. From a cardiological point of view, the patient presented a sudden drop in blood pressure, electrocardiographic anterior and infero-lateral ST depression, pericardial effusion and hypokinesia of the interventricular septum on echocardiography, and a significant increase in troponin T. Cardiac magnetic resonance imaging confirmed the myocarditis, with the presence of septal and anterior intramyocardial edema in T2 weighted sequences, with prolonged T2 time at T2 mapping analysis, without late gadolinium enhancement areas. Cardiological and general clinical conditions gradually improved only after the antivenom was administred. This is one of the rare cases of viper bite myocarditis with echocardiographic and magnetic resonance imaging documentation in Europe; it emphasizes the importance of identifying uncommon complications of venomous snake-bites and the prompt administration of antivenom, even though snake bites are less frequent at our latitudes.

A Guide to the Clinical Management of Vipera Snakebite in Italy

The genus Vipera encompasses most species of medically significant venomous snakes of Europe, with Italy harbouring four of them. Envenomation by European vipers can result in severe consequences, but underreporting and the absence of standardised clinical protocols hinder effective snakebite management. This study provides an updated, detailed set of guidelines for the management and treatment of Vipera snakebite tailored for Italian clinicians. It includes taxonomic keys for snake identification, insights into viper venom composition, and recommendations for clinical management. Emphasis is placed on quick and reliable identification of medically relevant snake species, along with appropriate first aid measures. Criteria for antivenom administration are outlined, as well as indications on managing potential side effects. While the protocol is specific to Italy, its methodology can potentially be adapted for other European countries, depending on local resources. The promotion of comprehensive data collection and collaboration among Poison Control Centres is advocated to optimise envenomation management protocols and improve the reporting of epidemiological data concerning snakebite at the country level.

Acute compartment syndrome and fasciotomy after a viper bite in Italy: a case report

BACKGROUND

Bites caused by European vipers are rare medical emergencies but can occasionally cause life-threatening complications. Viper venom causes local symptoms, which can be accompanied by systemic manifestations in severe cases. The local effects of snakebites include edema and, more rarely, necrosis and compartment syndrome. The consequences of envenomation are often more pronounced in children due to their smaller body size.

CASE PRESENTATION

We present the case of a 6-year-old girl who experienced multiple viper bites in the lower limb in northwest Italy. The girl received supportive care but progressed to develop compartment syndrome that required emergency fasciotomy. The patient's condition improved promptly after surgical decompression and administration of antivenom, but full recovery required prolonged hospitalization and rehabilitation.

CONCLUSIONS

This case highlights the importance of obtaining a timely assessment of the severity of viper envenomation without delaying the administration of antivenom in most serious cases. The presence of multiple bite marks on the patient is one factor that may help to predict the clinical severity of snakebites and anticipate symptom progression.

An agonist of CXCR4 induces a rapid recovery from the neurotoxic effects of Vipera ammodytes and Vipera aspis venoms

People bitten by Alpine vipers are usually treated with antivenom antisera to prevent the noxious consequences caused by the injected venom. However, this treatment suffers from a number of drawbacks and additional therapies are necessary. The venoms of Vipera ammodytes and of Vipera aspis are neurotoxic and cause muscle paralysis by inducing neurodegeneration of motor axon terminals because they contain a presynaptic acting sPLA2 neurotoxin. We have recently found that any type of damage to motor axons is followed by the expression and activation of the intercellular signaling axis consisting of the CXCR4 receptor present on the membrane of the axon stump and of its ligand, the chemokine CXCL12 released by activated terminal Schwann cells. We show here that also V. ammodytes and V. aspis venoms cause the expression of the CXCL12-CXCR4 axis. We also show that a small molecule agonist of CXCR4, dubbed NUCC-390, induces a rapid regeneration of the motor axon terminal with functional recovery of the neuromuscular junction. These findings qualify NUCC-390 as a promising novel therapeutics capable of improving the recovery from the paralysis caused by the snakebite of the two neurotoxic Alpine vipers.

Neurological and neuro-ophthalmological manifestations of snake bite: a systematic review

Objective

Snakebites, a major health concern in developing countries, affect rural farming communities. Venom, primarily neurotoxin, injected during a snake bite disrupts the nervous system, causing symptoms like muscle weakness, paralysis, altered sensation, and coordination issues. This review focuses on evaluating neurological and neuro-ophthalmological manifestations associated with snakebites.

Methods

A database search was conducted in EMBASE and PubMed for studies published from 2000 to 2023. The investigation centered on examining neurological and neuro-ophthalmological symptoms and signs, treatment approaches, treatment outcomes, and long-term complications of snake bites.

Results

Neurological and neuro-ophthalmological symptoms were common in both neurotoxic and hemotoxic snake bites, especially in neurotoxic cases. Ptosis was a prevalent manifestation across various snake bites, along with respiratory paralysis, limb weakness, dysphasia, and visual disturbances in some instances. However, most patients improved without residual neurological symptoms after treatment.

Conclusions

Understanding patterns of neurological manifestations contributes valuable insights for the comprehensive management of snakebite.

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 Are the Neurotoxins in Hemotoxic Snake Venoms?

Snake venoms as tools for hunting are primarily aimed at the most vital systems of the prey, especially the nervous and circulatory systems. In general, snakes of the Elapidae family produce neurotoxic venoms comprising of toxins targeting the nervous system, while snakes of the Viperidae family and most rear-fanged snakes produce hemotoxic venoms directed mainly on blood coagulation. However, it is not all so clear. Some bites by viperids results in neurotoxic signs and it is now known that hemotoxic venoms do contain neurotoxic components. For example, viperid phospholipases A₂ may manifest pre- or/and postsynaptic activity and be involved in pain and analgesia. There are other neurotoxins belonging to diverse families ranging from large multi-subunit proteins (e.g., C-type lectin-like proteins) to short peptide neurotoxins (e.g., waglerins and azemiopsin), which are found in hemotoxic venoms. Other neurotoxins from hemotoxic venoms include baptides, crotamine, cysteine-rich secretory proteins, Kunitz-type protease inhibitors, sarafotoxins and three-finger toxins. Some of these toxins exhibit postsynaptic activity, while others affect the functioning of voltage-dependent ion channels. This review represents the first attempt to systematize data on the neurotoxins from "non-neurotoxic" snake venom. The structural and functional characteristic of these neurotoxins affecting diverse targets in the nervous system are considered.

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.

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.

Early effects of viper envenomation on retina and optic nerve blood flow: An optical coherence tomography angiography study

In this study, the early retinal and optic nerve blood flows of patients exposed to Viper bite were evaluated with non-invasive optical coherence tomography angiography (OCTA) and compared with healthy controls. The retinal and optic disc OCTA data of 31 victims of viper bite (group S) without systemic envenomation clinical symptoms and 31 healthy controls (group C) were compared. Only patients with early signs of envenomation were included in the study. Optical coherence tomography angiographies were performed with RTVue XR Avanti with AngioVue software. Vascular densities in the whole image, foveal, parafoveal regions at the superficial and the deep capillary plexus segments were acquired and statistically analyzed. The flow area parameters were measured in the superficial retinal capillary plexus, deep retinal capillary plexus, outer retinal capillary plexus, and choriocapillaris layers of the macula in 1-mm and 3-mm diameter areas. The peripapillary flow areas were measured for the optic nerve head, vitreous, radial peripapillary capillary (RPC), and choroid in a 4.50-mm diameter area. Foveal and parafoveal thicknesses were also measured and compared. The average hospital admission time of the patients in group S was 1.24 ± 0.75 (0.50-3.00) hours. Age (p = 0.103) and gender (p = 0.714) were similar in both groups. Superficial (p = 0.010), deep flow areas (p = 0.034), and superficial parafoveal vascular density (p = 0.001) were significantly reduced in group S compared to group C. The outer retinal flow area (p < 0.001) increased significantly in group S. Nerve head flow area (p = 0.035), one of the optic disc flow areas, was found to be decreased in group S. Notably, foveal (p < 0.001) and parafoveal (p = 0.003) thicknesses and superficial (p = 0.001) and deep (p < 0.001) foveal vascular densities were greater in group S. Compared to group C, the superficial (p = 0.009) and deep (p = 0.009) foveal flow areas in the central foveal area with a diameter of 1 mm increased significantly in group S. Viper venom may cause blood flow changes in the retina and optic disc and an increase in retinal thickness in the early period although there are no signs of systemic envenomation.

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.

Comparison of Preclinical Properties of Several Available Antivenoms in the Search for Effective Treatment of Vipera ammodytes and Vipera berus Envenoming

Snakebites are a relatively rare medical emergency in Europe. In more than half of the annual cases caused by Vipera ammodytes, Vipera berus, and Vipera aspis, immunotherapy with animal-derived antivenom is indicated. Among eight products recently identified as available against European medically relevant species, only Zagreb antivenom, Viperfav, and ViperaTAb have been used almost exclusively for decades. Zagreb antivenom comprises V. ammodytes-specific F(ab')₂ fragments. Viperfav is a polyspecific preparation based on F(ab')₂ fragments against V. aspis, V. berus, and V. ammodytes venoms. ViperaTAb contains Fab fragments against the venom of V. berus. In 2014 the production of Zagreb antivenom was discontinued. Additionally, in the period of 2017 to 2018 a shortage of Viperfav occurred. Due to a lack of the product indicated for the treatment of V. ammodytes bites, other antivenoms were implemented into clinical practice without comparative assessment of their eligibility. The aim of our work was to identify a high-quality antivenom that might ensure the successful treatment of V. ammodytes and V. berus bites at the preclinical level. Differentiation between bites from these two species is difficult and unreliable in clinical practice, so the availability of a unique antivenom applicable in the treatment of envenoming caused by both species would be the most advantageous for Southeastern Europe. Zagreb antivenom, Viperfav, and ViperaTAb, as well as Viper venom antitoxin for V. berus envenoming and the in-development Inoserp Europe, which was designed to treat envenoming caused by all medically important European snakes, were comparatively tested for the first time. Emphasis was placed on their physicochemical properties, primarily purity and aggregate content, as well as their in vivo protective efficacies. As Zagreb antivenom is no longer available on the European market, Viperfav is the highest-quality product currently available and the only antivenom whose neutralisation potency against V. ammodytes and V. berus venoms was above regulatory requirements.

Vipers of Major clinical relevance in Europe: Taxonomy, venom composition, toxicology and clinical management of human bites

Snakebites in Europe are mostly due to bites from Viperidae species of the genus Vipera. This represents a neglected public health hazard with poorly defined incidence, morbidity and mortality. In Europe, fourteen species of "true vipers" (subfamily Viperinae) are present, eleven of which belong to the genus Vipera. Amongst these, the main medically relevant species due to their greater diffusion across Europe and the highest number of registered snakebites are six, namely: Vipera ammodytes, V. aspis, V. berus, V. latastei, V. seoanei and V. ursinii. Generally speaking, viper venom composition is characterised by many different toxin families, like phospholipases A2, snake venom serine proteases, snake venom metalloproteases, cysteine-rich secretory proteins, C-type lectins, disintegrins, haemorrhagic factors and coagulation inhibitors. A suspected snakebite is often associated with severe pain, erythema, oedema and, subsequently, the onset of an ecchymotic area around one or two visible fang marks. In the field, the affected limb should be immobilised and mildly compressed with a bandage, which can then be removed once the patient is being treated in hospital. The clinician should advise the patient to remain calm to reduce blood circulation and, therefore, decrease the spread of the toxins. In the case of pain, an analgesic therapy can be administered, the affected area can be treated with hydrogen peroxide or clean water. However, anti-inflammatory drugs and disinfection with alcohol or alcoholic substances should be avoided. For each patient, clinical chemistry and ECG are always a pre-requisite as well as the evaluation of the tetanus immunisation status and for which immunisation may be provided if needed. The treatment of any clinical complication, due to the envenomation, does not differ from treatments of emergency nature. Antivenom is recommended when signs of systemic envenomation exist or in case of advanced local or systemic progressive symptoms. Recommendations for future work concludes. The aim of this review is to support clinicians for the clinical management of viper envenomation, through taxonomic keys for main species identification, description of venom composition and mode of action of known toxins and provide a standardised clinical protocol and antivenom administration.

Vipera snakebite in Europe: a systematic review of a neglected disease

In 2009, snakebites were included in the list of the World Health Organization (WHO) neglected diseases. Dermatological literature lacks current and up-to-date articles about snakebites and their management, despite the fact that dermatologists, especially from rural hospitals, can be called into the emergency room to consult the management of suspected snakebites. In this systematic review, we highlighted the main clinical and laboratory aspects of snakebites from Vipera spp. in Europe, by reviewing 3574 studies initially retrieved from PubMed, Embase and Cochrane CENTRAL databases. Of these, 78 were finally included in the systematic review. We found that the most involved taxon was V. berus in 63.3% and the most involved anatomic site of the bite was the upper limbs 53.1% with fang marks reported in 90.5%. The mean age of the patients was 32.9 years, and bites were slightly more common among males (58.2%). A wound washing was performed in 86.9% of cases before the hospitalization. The most frequently reported grade of envenomation was G2 (42.2%). In addition to local dermatological symptoms (extended erythema, oedema, cutaneous necrosis, hives, purpura, petechiae, acute compartment syndrome), numerous systemic symptoms have also been reported, including fatigue (14.4%), pain (75.3%), fever (49.2%), direct anaphylactoid reaction (5.3%), anxiety (60.8%), cranial nerve neurotoxicity (14.8%), dysesthesia/paraesthesia (7.9%), vomiting (33.7%), abdominal pain (23.3%), diarrhoea (15.4%), dyspnoea (6.3%), proteinuria (10.6%) and haematuria (9.3%). Secondary infections were present in 3.5% and disseminated intravascular coagulation in 3.1% of cases, and fasciotomy was performed in 4.2% cases, while an amputation in 6.9%. Only 0.9% of patients died. Antivenom was administered in 3053 cases. In conclusion, there is a pressing need for robust multi-centre randomized control trials, standardized protocol for snakebite management and antivenom administration across Europe and a National snakebite register for each European country.

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.

Extending knowledge of the clinical picture of Balkan adder (Vipera berus bosniensis) envenoming: The first photographically-documented neurotoxic case from South-Western Hungary

We report a severe envenoming associated with minimal local symptoms following a Balkan adder (Vipera berus bosniensis) bite in South-Western Hungary. A 63-year-old male with a history of hypertension and sinus bradycardia (45/min) was bitten by a sub-adult specimen of V. b. bosniensis in Somogy County on 04 May 2017. The patient was transported to and treated at the Emergency Department of "Moritz Kaposi" General Hospital, Kaposvár. Locally only pain and minimal swelling with a small haematoma developed on the bitten finger. The abdominal muscles were very tender and guarding was detected upon palpation on the way to hospital. The patient, who had taken his telmisartan (80 mg) tablet in that morning, complained of nausea and dizziness during the first medical examination. The systemic signs included fluctuations in blood pressure (115/85-165/105 mmHg), ECG changes (transient horizontal ST depression in V5-6, and sinus tachycardia (90/min)), severe diarrhoea and vomiting (in 7 episodes). Descending neuromuscular paralysis appeared in the next morning, including complete bilateral ptosis with external ophthalmoplegia, and binocular diplopia. Single-fiber electromyography confirmed the neuromuscular block in the frontalis muscle innervated by the facial nerve. Intense dizziness with uncoordinated movement emerged on the 3rd day. The laboratory findings were mild, including anaemia, hypokalaemia, elevated glutamic-pyruvic transaminase and C-reactive protein levels. The absolute neutrophil count remained almost completely normal. Supportive care and monovalent antivenom (Viper Venom Antitoxin^®, Biomed, Warsaw) were applied. The patient was discharged from hospital on the 4th day, although recovery was not complete until 9 days after the bite. This is the first photographically-documented case of neurotoxic envenoming from the South-Western Hungarian distribution range of V. b. bosniensis.

Antivenom for European Vipera species envenoming

BACKGROUND

European viper bite is relatively uncommon but can cause serious envenoming, particularly swelling and hemorrhage spreading from limb to trunk that can cause long term disability. Systemic features are relatively mild compared to many other venomous species. Moderate-to-severe envenoming requires antivenom, which is given many hundreds of times each year across the continent. Several Vipera spp antivenoms are produced in Europe, but there is little comparative information available for the antivenoms and none is licensed with the European Medicines Agency. We aimed to collect descriptive data on European viper antivenoms and assess their relative effectiveness.

METHODS

A systematic review of articles relating to antivenom in Europe was performed using the Medline medical database. The following keywords "Europ*" or the individual names of each European country and "antiven*" or "immun*" or "envenom*" and "snake" or "viper*" or "adder" were used. Articles published between 1 January 1996 and 11 March 2016 pertaining to clinical outcome, including case reports, were selected. Referenced articles in the indexed articles were explored for suitability and included if they met any of the criteria: specific antivenom used, route of antivenom administration, adverse reactions to antivenom therapy and length of hospital admission. All accepted abstracts from EAPCCT conferences since 2000 were searched and abstracts relating to Vipera spp envenoming were assessed for suitability. We extracted data on study type, safety and effectiveness. We sought information on antivenoms from manufacturers and individual patient data from authors of publications. Since individual patient data were only rarely available, we compared median length of stay between case series reporting each antivenom. We identified 40 papers and six published abstracts, and one unpublished paper that reported clinical cases and case series of envenomed patients treated with antivenom. No publication reported randomized controlled trials comparing any European Vipera antivenom with either placebo or another antivenom. 25 reports were of retrospective hospital- (n = 13) or poison center-based (n = 12) case series including five or more patients; a further 12 reports were either case reports or case series with less than five patients and one paper was a limited literature review. An additional nine papers reported prospective data; seven collected data remotely through poison service telephone communication with the attending physicians. Antivenoms available in Europe: Eight antivenoms are available for European Vipera spp envenoming; a material safety data sheet providing information on manufacture was available for seven. Six are raised against V. berus or V. ammodytes venom; the seventh is raised against a mixture of V. ammodytes, V. aspis and V. berus venom and the eighth is raised against V. ammodytes, Macrovipera lebetina and Montivipera xanthina venom. Six manufacturers recommended intramuscular administration while two recommended intravenous administration. No randomized control trials comparing the effectiveness of antivenoms were identified. Pre-clinical data: We found two papers presenting comparative preclinical data. Clinical data: Clinical studies were predominantly retrospective and contained clinical data on antivenom used in 2602 patients; where the antivenom was identified (n = 2174), 2061 (94.8%) received Zagreb, ViperFAV or ViperaTAb antivenoms. There were few published data on the other antivenoms. Repeated use of antivenom: Repeat doses were reported in 230/1491 of cases (15.4%) where this information was recorded. Outcome and length of hospital stay: Intravenous administration of antivenom was associated with shorter length of hospital stay (median length of hospital stay in studies of intravenous ViperFAV or ViperaTAb ranged from 1 to 4.8 days versus 2 to 18 days for intramuscular Bulbio or Zagreb antivenoms). Antivenom versus no antivenom: Some small studies demonstrated no difference in the length of hospital stay in patients with equivalent envenomation grading who either did or did not receive antivenom. Adverse events: Adverse reactions were reported in 37 of 2408 cases (1.5%) including seven cases of anaphylaxis.

CONCLUSIONS

There are very limited pre-clinical comparative data and no randomised controlled trials assessing effectiveness of the antivenoms against different Vipera species. Most descriptive data suggest the efficacy of Zagreb, ViperFAV and ViperaTAb antivenoms by the intravenous route but not intramuscular route, although this is level D evidence. Reported adverse reactions were rare, suggesting that the modern intravenous antivenoms are of good quality. Better and more systematic data, including perhaps randomized controlled trials comparing different antivenoms, are required for the many hundreds of antivenom administrations that occur annually across Europe.

Cardiotoxic effects of the Vipera ammodytes ammodytes venom fractions in the isolated perfused rat heart

The nose-horned viper (Vipera ammodytes ammodytes) is the most venomous European snake. Its venom is known as haematotoxic, myotoxic and neurotoxic but it exerts also cardiotoxic effects. To further explore the cardiotoxicity of the venom we separated it into four fractions by gel filtration chromatography. Three fractions that contain polypeptides (A, B, and C) were tested for their effects on isolated rat heart. Heart rate (HR), incidence of arrhythmias (atrioventricular (AV) blocks, ventricular tachycardia, ventricular fibrillation, and asystolia), coronary flow (CF), systolic, developed and diastolic left ventricular pressure (LVP) were measured before, during, and after the application of venom fractions in three different concentrations. Fraction A, containing proteins of 60-100 kDa, displayed no effect on the rat heart. Fractions B and C disturbed heart functioning in similar way, but with different potency that was higher by the latter. This was manifested by significant decrease of HR and CF, the increase of diastolic, and the decrease of systolic and developed LVPs. All hearts treated with fraction C in the final CF concentrations 22.5 and 37.5 μg/mL suffered rapid and irreversible asystolia without AV blockade. They underwent also ventricular fibrillation and ventricular tachycardia. Fraction B affected hearts only at the highest dose inducing asystolia in all hearts, ventricular fibrillation in 80% and ventricular tachycardia in 70% of the hearts. Venom fraction C induced 71% of all recorded heart rhythm disturbances, significantly more than fraction B, which induced 29%. Most abundant proteins in fraction C were secreted phospholipases A₂ among which the venom component acting on the heart is most probably to be looked for.

Venomous snakebites in children in southern Croatia

This retrospective study represents observation of 160 children and adolescents aged up to 18 years that experienced venomous snakebites in southern Croatia and were treated in the Clinical Department of Infectious Diseases in the University Hospital Centre Split from 1979 to 2013. The main purpose of this research was to determine the epidemiological characteristics, clinical presentation, local and general complications, and received treatment. Most bites occurred during warm months, from early May to late August (80%), mostly in May and June. Upper limb bites were more frequent (59%) than lower limb bites (40%). Out of the total number of poisoned children, 24% developed local, and 25% general complications. The most common local complications were haemorrhagic blisters that occurred in 20% children, followed by compartment syndrome presented in 7.5% patients. The most dominated general complication was cranial nerve paresis or paralysis, which was identified in 11.2% patients, whereas shock symptoms were registrated in 7% children. According to severity of poisoning, 9.4% children had minor, 35% mild, 30.6% moderate, and 24.4% had severe clinical manifestation of envenomation. Only one (0.6%) child passed away because of snakebite directly on the neck. All patients received antivenom produced by the Institute of Immunology in Zagreb, tetanus prophylaxis as well, and almost all of them received antibiotics, and a great majority of them also received corticosteroids and antihistamines. Neighter anaphylactic reaction nor serum disease were noticed in our patients after administrating antivenom. A total of 26% children underwent surgical interventions, and incision of haemorrhagic blister was the most common applied surgical treatment, which was preformed in 15.6% patients, while fasciotomy was done in 7.5% subjects. All of our surgically treated patients recovered successfully.

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.