European viper envenomings: Assessment of Viperfav™ and other symptomatic treatments

Suspected envenomation by the common European adder (Vipera berus berus) in 28 horses in Finland

Vipera berus berus is the only venomous snake present in the Nordic countries and cases of envenomation in horses are reported during the warmer months. Little is known about the presentation, treatment and survival of horses with common European adder envenomation. Clinical and laboratory findings, treatment and outcome are reported for 28 horses admitted to Helsinki University Equine Hospital in 2008-2023 due to suspicion of snake bite. Eleven of these horses received antivenom treatment. Other common treatments included non-steroidal anti-inflammatories (22/28), antimicrobials (19/28), intravenous fluid therapy (11/28), corticosteroids (9/28) and local treatment (11/28). All horses survived until discharge. No difference was detected in the length of hospital stay between horses with moderate envenomation that had or had not received antivenom treatment. Horses with moderate envenomation are more likely to receive antivenom treatment and require longer hospital stay than horses with mild envenomation. Antivenom treatment is not associated with shorter hospital stay. Little evidence supports the use of corticosteroids and antibiotics in treatment of envenomation. Studies with larger numbers of animals are warranted to evaluate the effect of treatment, including administration of antivenom, on long-term outcome and survival from envenomation.

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.

Management Strategies for Common Animal Bites in Pediatrics: A Narrative Review on the Latest Progress

Animal bites are a common reason for children to visit primary care and emergency departments. Dog bites are the most prevalent, followed by cat bites at 20-30%. Other animals such as bats, monkeys, snakes, and rats collectively contribute less than 1% of cases. Hospitalization is necessary in only 4% of animal bite incidents. The main aim of this narrative review is to summarize the main protocols currently followed in pediatrics in cases involving the most common bites from different animal species. Analysis of the literature showed that the management of common animal bites in children presents a multifaceted challenge requiring a comprehensive understanding of the epidemiology, clinical presentation, and treatment modalities associated with each specific species. Effective wound management is paramount in reducing the risk of infection and promoting optimal healing outcomes. Additionally, tetanus vaccination status should be assessed and updated as necessary, and prophylactic antibiotics may be indicated in certain cases to prevent secondary infections. Furthermore, the role of rabies prophylaxis cannot be overstated, particularly in regions where rabies is endemic or following bites from high-risk animals. In addition to medical management, psychosocial support for both the child and their caregivers is integral to the overall care continuum. Future studies exploring the efficacy of novel treatment modalities, such as topical antimicrobial agents or advanced wound dressings, may offer new insights into optimizing wound healing and reducing the risk of complications.

Viper envenomation in Central and Southeastern Europe: a multicentre study

INTRODUCTION

Snakebite incidence varies across Europe. However, there is limited research from Central and Southeastern Europe. These regions are notable for the presence of the common European adder (Vipera berus) and the more venomous nose-horned viper (Vipera ammodytes). No standard European antivenom protocol exists. The aim was to assess the epidemiology and treatment of viper bites in this region, focusing on a comparison of bites from Vipera berus and Vipera ammodytes.

METHODS

We conducted a prospective multicenter study in Central and Southeastern Europe from 2018 to 2020. This study included poison centres and toxicology-associated hospital wards in Poland, the Czech Republic, Slovakia, Hungary, Slovenia, Croatia, Serbia, and Bulgaria. The following data were collected: age, gender, Vipera species, snakebite site, clinical picture, laboratory results, Audebert's clinical severity grading score, and antivenom therapy.

RESULTS

The annual incidence of viper bites in Central and Southeast Europe was estimated at 2.55 bites per million population. Within their respective geographical distribution areas, the incidence of Vipera ammodytes bites (1.61 bites per million population) was higher than Vipera berus bites (1.00 bites per million population). Patients bitten by Vipera ammodytes more frequently reported local pain and developed thrombocytopenia. Antivenom treatment was more commonly administered in Vipera ammodytes bites (72%) compared to Vipera berus bites (39%). The incidence of Vipera ammodytes bites treated with antivenom within its geographical distribution area was three times higher than Vipera berus bites treated with antivenom (1.16 bites per million population versus 0.39 bites per million population). No deaths were reported.

CONCLUSIONS

The estimated incidence of viper bites in Central and Southeastern Europe is at least 2.55 per million population. Vipera ammodytes bites are more common and severe, characterized by higher frequencies of pain and thrombocytopenia. Antivenom is needed more often for Vipera ammodytes bites. It is vital that enough European Medicines Agency-approved Vipera ammodytes antivenom is produced and offered affordably.

Snake Antivenoms-Toward Better Understanding of the Administration Route

Envenomations induced by animal bites and stings constitute a significant public health burden. Even though a standardized protocol does not exist, parenterally administered polyclonal antivenoms remain the mainstay in snakebite therapy. There is a prevailing opinion that their application by the i.m. route has poor efficacy and that i.v. administration should preferentially be chosen in order to achieve better accomplishment of the antivenom therapeutic activity. Recently, it has been demonstrated that neutralization not only in the systemic circulation but also in the lymphatic system might be of great importance for the clinical outcome since it represents another relevant body compartment through which the absorption of the venom components occurs. In this review, the present-day and summarized knowledge of the laboratory and clinical findings on the i.v. and i.m. routes of antivenom administration is provided, with a special emphasis on the contribution of the lymphatic system to the process of venom elimination. Until now, antivenom-mediated neutralization has not yet been discussed in the context of the synergistic action of both blood and lymph. A current viewpoint might help to improve the comprehension of the venom/antivenom pharmacokinetics and the optimal approach for drug application. There is a great need for additional dependable, practical, well-designed studies, as well as more practice-related experience reports. As a result, opportunities for resolving long-standing disputes over choosing one therapeutic principle over another might be created, improving the safety and effectiveness of snakebite management.

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.

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.

Isolated Ptosis Following a Vipera aspis Bite

In Spain, snakebites are uncommon medical emergencies that cause barely 100 hospitalizations annually. Most of the venomous bites are by snakes of the Viperidae family. Venom from Vipera snakes is reported to have cytotoxic and hematotoxic effects, and neurological effects have also been described. Ptosis (cranial nerve III palsy) is the most common sign, although any cranial nerve can be affected. We describe isolated ptosis, which was very likely after a Vipera aspis bite in the East Catalonian Pyrenees. No antivenom was administered. The ptosis resolved spontaneously within 10 h. Although neurologic findings are usually mild, they indicate a moderate or severe envenomation. Treating snakebites can be challenging for clinicians, especially when there are uncommon clinical manifestations. A toxicologist at a poison center should be consulted to help guide management. Development of local protocols may provide clinical support.

Bioactive Molecules Derived from Snake Venoms with Therapeutic Potential for the Treatment of Thrombo-Cardiovascular Disorders Associated with COVID-19

As expected, several new variants of Severe Acute Respiratory Syndrome-CoronaVirus-2 (SARS-CoV-2) emerged and have been detected around the world throughout this Coronavirus Disease of 2019 (COVID-19) pandemic. Currently, there is no specific developed drug against COVID-19 and the challenge of developing effective antiviral strategies based on natural agents with different mechanisms of action becomes an urgent need and requires identification of genetic differences among variants. Such data is used to improve therapeutics to combat SARS-CoV-2 variants. Nature is known to offer many biotherapeutics from animal venoms, algae and plant that have been historically used in traditional medicine. Among these bioresources, snake venom displays many bioactivities of interest such as antiviral, antiplatelet, antithrombotic, anti-inflammatory, antimicrobial and antitumoral. COVID-19 is a viral respiratory sickness due to SARS-CoV-2 which induces thrombotic disorders due to cytokine storm, platelet hyperactivation and endothelial dysfunction. This review aims to: (1) present an overview on the infection, the developed thrombo-inflammatory responses and mechanisms of induced thrombosis of COVID-19 compared to other similar pathogenesis; (2) underline the role of natural compounds such as anticoagulant, antiplatelet and thrombolytic agents; (3) investigate the management of coagulopathy related to COVID-19 and provide insight on therapeutic such as venom compounds. We also summarize the updated advances on antiviral proteins and peptides derived from snake venoms that could weaken coagulopathy characterizing COVID-19.

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.

Intravenous Vipera berus Venom-Specific Fab Fragments and Intramuscular Vipera ammodytes Venom-Specific F(ab')2 Fragments in Vipera ammodytes-Envenomed Patients

Vipera ammodytes (V. ammodytes) is the most venomous European viper. The aim of this study was to compare the clinical efficacy and pharmacokinetic values of intravenous Vipera berus venom-specific (paraspecific) Fab fragments (ViperaTAb) and intramuscular V. ammodytes venom-specific F(ab’)₂ fragments (European viper venom antiserum, also called “Zagreb” antivenom) in V.ammodytes-envenomed patients. This was a prospective study of V.ammodytes-envenomed patients that were treated intravenously with ViperaTAb or intramuscularly with European viper venom antiserum that was feasible only due to the unique situation of an antivenom shortage. The highest venom concentration, survival, length of hospital stay and adverse reactions did not differ between the groups. Patients treated with intravenous Fab fragments were sicker, with significantly more rhabdomyolysis and neurotoxicity. The kinetics of Fab fragments after one or more intravenous applications matched better with the venom concentration in the early phase of envenomation compared to F(ab’)₂ fragments that were given intramuscularly only on admission. F(ab’)₂ fragments given intramuscularly had 25-fold longer apparent total body clearance and 14-fold longer elimination half-time compared to Fab fragments given intravenously (2 weeks vs. 24 h, respectively). In V.ammodytes-envenomed patients, the intramuscular use of specific F(ab’)₂ fragments resulted in a slow rise of antivenom serum concentration that demanded their early administration but without the need for additional doses for complete resolution of all clinical signs of envenomation. Intravenous use of paraspecific Fab fragments resulted in the immediate rise of antivenom serum concentration that enabled their use according to the clinical progress, but multiple doses might be needed for efficient therapy of thrombocytopenia due to venom recurrence, while the progression of rhabdomyolysis and neurotoxic effects of the venom could not be prevented.

Moderate-to-severe Vipera berus envenoming requiring ViperaTAb antivenom therapy in the UK

BACKGROUND

Bites by the European adder (Vipera berus) in the UK are uncommon but potentially life threatening, and can be associated with marked limb swelling and disability. Following an interruption in Zagreb Imunološki zavod antivenom supply around 2012, the UK changed its national choice of antivenom for Vipera berus to ViperaTAb, an ovine Fab monospecific antivenom. In the absence of randomised controlled trials, we established an audit to review its use in clinical practice.

METHODS

A prospective audit of ViperaTAb use was conducted from March 2016 until November 2020 by the UK National Poison Information Service (NPIS). Users of the NPIS online toxicology database, TOXBASE, considering the use of antivenom for V. berus envenoming were invited to discuss the case with the on-call clinical toxicology consultant. Information was collected prospectively on indications, administration, adverse reactions and outcome of patients administered ViperaTAb antivenom.

RESULTS

One hundred and seventy patients were administered ViperaTAb antivenom over five years. One hundred and thirty-two were adults and 38 children (median age and range: 38, 2-87 years). Bites occurred across the UK, but most commonly in coastal regions of Wales and of South-West and East England. Median time to presentation was 2.1 (IQR 1.5-4.0) h and to antivenom administration from presentation was 2.0 (IQR 0.9-3.6) h. A minority of patients presented to hospital more than 12 h after being bitten (n = 19, 11.2%) or received antivenom more than 12 h after presenting to hospital (n = 17, 10.0%). Features of systemic envenoming were present in 64/170 (37.6%) patients, including 23 (13.5%) with anaphylaxis and 26 (15.3%) with hypotension (nine with both). Clinician assessment considered the initial antivenom to have been effective in 122/169 (72.2%) patients. Repeated dosing was common, occurring in 55/169 (32.5%), predominantly due to persisting or worsening local effects (46/51, 90.2%). There were three cases of probable early adverse reaction. No deaths occurred during the study. Complications of envenoming were rare but included four patients that underwent surgery, three patients each with acute kidney injury, mild coagulopathy, or thrombocytopenia (one severe). The median duration of hospital stay was 43.7 (IQR 22.5-66.5) h, longer for children than adults (52.5 vs 41.3 h).

CONCLUSION

ViperaTAb antivenom appears to be effective and safe and should be administered as soon as possible for patients meeting clinical criteria. Patients require close observation following antivenom to detect adverse reactions and progression or recurrence of envenoming. Close collaboration with expert NPIS consultant advice can help optimise antivenom timing, ensure repeated dosing is given appropriately, and avoid unnecessary surgical intervention. All hospitals, particularly those located in areas of relatively high incidence, should stock sufficient antivenom available at short notice, 24 h a day.

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.

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.

Extended Snake Venomics by Top-Down In-Source Decay: Investigating the Newly Discovered Anatolian Meadow Viper Subspecies, Vipera anatolica senliki

Herein, we report on the venom proteome of Vipera anatolica senliki, a recently discovered and hitherto unexplored subspecies of the critically endangered Anatolian meadow viper endemic to the Antalya Province of Turkey. Integrative venomics, including venom gland transcriptomics as well as complementary bottom-up and top-down proteomics analyses, were applied to fully characterize the venom of V. a. senliki. Furthermore, the classical top-down venomics approach was extended to elucidate the venom proteome by an alternative in-source decay (ISD) proteomics workflow using the reducing matrix 1,5-diaminonaphthalene. Top-down ISD proteomics allows for disulfide bond counting and effective de novo sequencing-based identification of high-molecular-weight venom constituents, both of which are difficult to achieve by commonly established top-down approaches. Venom gland transcriptome analysis identified 96 toxin transcript annotations from 18 toxin families. Relative quantitative snake venomics revealed snake venom metalloproteinases (42.9%) as the most abundant protein family, followed by several less dominant toxin families. Online mass profiling and top-down venomics provide a detailed insight into the venom proteome of V. a. senliki and facilitate a comparative analysis of venom variability for the closely related subspecies, Vipera anatolica anatolica.

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.

A prospective multicenter observational study of Viperidae polyvalent immune F(ab')2 antivenom administration for the treatment of viper envenomation in dogs

OBJECTIVE

To test an equine-derived polyvalent viperid antivenom (EPVA) in the treatment of dogs with evidence of viper envenomation.

DESIGN

Prospective, multicenter observational study.

SETTING

Veterinary emergency and critical care hospitals.

ANIMALS

A total of 82 client-owned dogs with progressive clinical signs after viperid snakebite were enrolled in the study.

INTERVENTIONS

Equine-derived polyvalent viperid antivenom was administered at a dosage of 1 mL/kg body weight, either by IV infusion or SC injection.

MEASUREMENTS AND MAIN RESULTS

A standardized snakebite severity score (SSS) was used to characterize the severity of envenomation and the clinical course after EPVA treatment. Most dogs had improved SSS both at 4 (65.8%) and 8 hours (81.7%) following EPVA administration. Five dogs died. At the 4-week assessment, 3 dogs had slightly abnormal hematological or coagulation parameters; all other surviving dogs showed no abnormalities. Antivenom-related acute or intermediate reactions occurred in 12 dogs (14.6%).

CONCLUSIONS

In the first study on antivenom in dogs in Italy, the effects of progressive viper envenomation were stabilized or reversed in the large majority of dogs receiving EPVA, as confirmed by the SSS analyses.

Preclinical Assessment of a New Polyvalent Antivenom (Inoserp Europe) against Several Species of the Subfamily Viperinae

The European continent is inhabited by medically important venomous Viperinae snakes. Vipera ammodytes, Vipera berus, and Vipera aspis cause the greatest public health problems in Europe, but there are other equally significant snakes in specific regions of the continent. Immunotherapy is indicated for patients with systemic envenoming, of which there are approximately 4000 annual cases in Europe, and was suggested as an indication for young children and pregnant women, even if they do not have systemic symptoms. In the present study, the safety and venom-neutralizing efficacy of Inoserp Europe-a new F(ab')₂ polyvalent antivenom, designed to treat envenoming by snakes in the Eurasian region-were evaluated. In accordance with World Health Organization recommendations, several quality control parameters were applied to evaluate the safety of this antivenom. The venom-neutralizing efficacy of the antivenom was evaluated in mice and the results showed it had appropriate neutralizing potency against the venoms of several species of Vipera, Montivipera, and Macrovipera. Paraspecificity of the antivenom was demonstrated as well, since it neutralized venoms of species not included in the immunization schemes and contains satisfactory levels of total proteins and F(ab')₂ fragment concentration. Therefore, this new polyvalent antivenom could be effective in the treatment of snake envenoming in Europe, including Western Russia and Turkey.

Vipera berus berus Venom from Russia: Venomics, Bioactivities and Preclinical Assessment of Microgen Antivenom

The common European adder, Vipera berus berus, is a medically relevant species, which is widely distributed in Russia and thus, is responsible for most snakebite accidents in Russia. We have investigated the toxic and enzymatic activities and have determined the proteomic composition of its venom. Phospholipases A₂ (PLA₂, 25.3% of the venom proteome), serine proteinases (SVSP, 16.2%), metalloproteinases (SVMP, 17.2%), vasoactive peptides (bradykinin-potentiating peptides (BPPs), 9.5% and C-type natriuretic peptides (C-NAP, 7.8%), cysteine-rich secretory protein (CRISP, 8%) and L-amino acid oxidase (LAO, 7.3%) represent the major toxin classes found in V. b. berus (Russia) venom. This study was also designed to assess the in vivo and in vitro preclinical efficacy of the Russian Microgen antivenom in neutralizing the main effects of V. b. berus venom. The results show that this antivenom is capable of neutralizing the lethal, hemorrhagic and PLA₂ activities. Third-generation antivenomics was applied to quantify the toxin-recognition landscape and the maximal binding capacity of the antivenom for each component of the venom. The antivenomics analysis revealed that 6.24% of the anti-V. b. berus F(ab’)₂ molecules fraction are toxin-binding antibodies, 60% of which represent clinically relevant antivenom molecules.

Severe Systemic Envenomation Following Vipera berus Bite Managed with ViperaTAb Antivenom

Bites by the European adder (Vipera berus) are a rare medical emergency in the UK with 20 to 50% of an estimated 50 to 200 cases per year necessitating treatment with antivenom. We present a case demonstrating both severe systemic and local effects necessitating out of hospital resuscitation, vasopressor support, and prolonged rehabilitation. Hemodynamic stability was restored promptly after administration of ViperaTAb antivenom, the first published case of its use in the UK.

Poor efficacy of preemptive amoxicillin clavulanate for preventing secondary infection from Bothrops snakebites in the Brazilian Amazon: A randomized controlled clinical trial

BACKGROUND

Secondary bacterial infections from snakebites contribute to the high complication rates that can lead to permanent function loss and disabilities. Although common in endemic areas, routine empirical prophylactic use of antibiotics aiming to prevent secondary infection lacks a clearly defined policy. The aim of this work was to estimate the efficacy of amoxicillin clavulanate for reducing the secondary infection incidence in patients bitten by Bothrops snakes, and, secondarily, identify risk factors for secondary infections from snakebites in the Western Brazilian Amazon.

METHODS AND FINDINGS

This was an open-label, two-arm individually randomized superiority trial to prevent secondary infection from Bothrops snakebites. The antibiotic chosen for this clinical trial was oral amoxicillin clavulanate per seven days compared to no intervention. A total of 345 patients were assessed for eligibility in the study period. From this total, 187 accomplished the inclusion criteria and were randomized, 93 in the interventional group and 94 in the untreated control group. All randomized participants completed the 7 days follow-up period. Enzyme immunoassay confirmed Bothrops envenoming diagnosis in all participants. Primary outcome was defined as secondary infection (abscess and/or cellulitis) until day 7 after admission. Secondary infection incidence until 7 days after admission was 35.5% in the intervention group and 44.1% in the control group [RR = 0.80 (95%CI = 0.56 to 1.15; p = 0.235)]. Survival analysis demonstrated that the time from patient admission to the onset of secondary infection was not different between amoxicillin clavulanate treated and control group (Log-rank = 2.23; p = 0.789).Secondary infections incidence in 7 days of follow-up was independently associated to fibrinogen >400 mg/dL [AOR = 4.78 (95%CI = 2.17 to 10.55; p<0.001)], alanine transaminase >44 IU/L [AOR = 2.52 (95%CI = 1.06 to 5.98; p = 0.037)], C-reactive protein >6.5 mg/L [AOR = 2.98 (95%CI = 1.40 to 6.35; p = 0.005)], moderate pain [AOR = 24.30 (95%CI = 4.69 to 125.84; p<0.001)] and moderate snakebites [AOR = 2.43 (95%CI = 1.07 to 5.50; p = 0.034)].

CONCLUSIONS/SIGNIFICANCE

Preemptive amoxicillin clavulanate was not effective for preventing secondary infections from Bothrops snakebites. Laboratorial markers, such as high fibrinogen, alanine transaminase and C-reactive protein levels, and severity clinical grading of snakebites, may help to accurately diagnose secondary infections.

TRIAL REGISTRATION

Brazilian Clinical Trials Registry (ReBec): RBR-3h33wy; UTN Number: U1111-1169-1005.

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.

Vipera ammodytes bites treated with antivenom ViperaTAb: a case series with pharmacokinetic evaluation

CONTEXT

In clinical practice it is difficult to differentiate between V. berus and V. ammodytes venomous bites. In the past this was not a concern, but due to the current shortage in Viperfav™ and European viper venom antiserum availability, V. a. ammodytes venomous bites have recently been treated with ViperaTAb^®, which is a pharmaceutical formulation containing a monospecific ovine Fab fragments against the venom of V. berus.

OBJECTIVE

To evaluate ViperaTAb^® in V. a. ammodytes envenomations.

MATERIALS AND METHODS

This is a prospective case series of three consecutive patients envenomed by V. a. ammodytes snakebite treated with ViperaTAb^®. V. ammodytes venom, neurotoxic ammodytoxins, and Fab fragment levels were determined in serum samples and a pharmacokinetic analysis of the antivenom Fab fragments was carried out.

RESULTS

Three patients bitten by V. a. ammodytes with extensive local swelling, neurological symptoms and recurrent thrombocytopenia were treated with ViperaTAb^®. V. ammodytes venom was detected in serum of all three patients. Ammodytoxins were detected in the serum of only the most severely envenomed patient who developed neurological symptoms. In the presented moderate cases, a dose of 8 mL of ViperaTAb^® reduced swelling and improved systemic effects, such as thrombocytopenia. However, this dose of ViperaTAb^® was not effective in the most severely envenomed patient with the highest serum values of V. ammodytes venom. In this case ViperaTAb^® did not stop local swelling and it had no effect on neurological signs. ViperaTAb^®'s systemic clearance, distribution and elimination half-lives were 4.3-13.4 mL/h/kg, 1.2-3.2 h and 14.1-55.4 h, respectively.

CONCLUSIONS

In patients envenomed by V. a. ammodytes venom, ViperaTAb^® reduces moderate swelling and temporarily improves systemic effects, except neurological symptoms. ViperaTAb^® application induces a decrement of V. ammodytes venom level in the blood, but did not affect serum concentration of neurotoxic ammodytoxins in the one patient with measurable concentrations.

Two decades of pharmacovigilance and clinical experience with highly purified rabies immunoglobulin F(ab')2 fragments

INTRODUCTION

Rabies is a worldwide zoonotic viral disease with no specific treatment once symptoms occur; manifest disease is almost always fatal. WHO recommendations for exposed individuals include immediate attention to the wound and use of rabies immunoglobulin and/or vaccine for post-exposure prophylaxis (PEP). Here, we provide an overview of the clinical experience with a highly purified preparation of F(ab')₂ fragments from equine rabies immunoglobulin (F(ab')₂ pERIG; Favirab^TM) in rabies PEP. Areas covered: Our review comprises a retrospective analysis of adverse event reports in the Sanofi Pasteur global pharmacovigilance database for F(ab')₂ pERIG, including adverse event reports from eight Sanofi Pasteur-sponsored clinical trials and post-market surveillance data collected between 1995 and 2014. The general safety profile of F(ab')₂ pERIG is discussed, as are the occurrence of rare anaphylactic reactions, and suspected intervention failure. Expert commentary: Over 20 years of clinical development and post-licensure experience has established the safety and effectiveness of F(ab')₂ pERIG (Favirab^TM) in rabies PEP.

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.

Benefits of using heterologous polyclonal antibodies and potential applications to new and undertreated infectious pathogens

BACKGROUND

Passive immunotherapy using polyclonal antibodies (immunoglobulins) has been used for over a century in the treatment and post-exposure prophylaxis of various infections and toxins. Heterologous polyclonal antibodies are obtained from animals hyperimmunised with a pathogen or toxin.

AIMS

The aims of this review are to examine the history of animal polyclonal antibody therapy use, their development into safe and effective products and the potential application to humans for emerging and neglected infectious diseases.

METHODS

A literature search of OVID Medline and OVID Embase databases was undertaken to identify articles on the safety, efficacy and ongoing development of polyclonal antibodies. The search contained database-specific MeSH and EMTREE terms in combination with pertinent text-words: polyclonal antibodies and rare/neglected diseases, antivenins, immunoglobulins, serum sickness, anaphylaxis, drug safety, post marketing surveillance, rabies, human influenza, Dengue, West Nile, Nipah, Hendra, Marburg, MERS, Hemorrhagic Fever Virus, and Crimean-Congo. No language limits were applied. The final search was completed on 20.06.2015. Of 1960 articles, title searches excluded many irrelevant articles, yielding 303 articles read in full. Of these, 179 are referenced in this study.

RESULTS

Serum therapy was first used in the 1890s against diphtheria. Early preparation techniques yielded products contaminated with reactogenic animal proteins. The introduction of enzymatic digestion, and purification techniques substantially improved their safety profile. The removal of the Fc fragment of antibodies further reduces hypersensitivity reactions. Clinical studies have demonstrated the efficacy of polyclonal antibodies against various infections, toxins and venoms. Products are being developed against infections for which prophylactic and therapeutic options are currently limited, such as avian influenza, Ebola and other zoonotic viruses.

CONCLUSIONS

Polyclonal antibodies have been successfully applied to rabies, envenomation and intoxication. Polyclonal production provides an exciting opportunity to revolutionise the prognosis of both longstanding neglected tropical diseases as well as emerging infectious threats to humans.

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.

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.

The effect of a single dose of prednisolone in dogs envenomated by Vipera berus--a randomized, double-blind, placebo-controlled clinical trial

BACKGROUND

Treatment with glucocorticoids after snakebite in dogs is controversial and randomized clinical studies are missing. The objective of this study was to investigate the effect of a single dose of prednisolone in dogs envenomated by Vipera berus in a double-blind placebo-controlled study, after exclusion of dogs treated with antivenom. The two treatment groups were compared regarding clinical status and clinicopathological test results. A total of 75 dogs bitten by Vipera berus within the previous 24 hours were included. Clinical assessment, blood sampling and measurement of the bitten body part were done at admission (Day 1), after 24 hours (Day 2) and at a re-examination (Re-exam) after 10-28 days. Dogs were given prednisolone 1 mg/kg bodyweight (PRED) or saline (PLACEBO) subcutaneously in a randomized, double-blind clinical trial. Dogs were examined clinically and mental status and extent of edema were described. Furthermore, appetite, vomiting, diarrhea, cardiac arrhythmia and death were recorded. Concentrations of C-reactive protein (CRP) and high sensitivity cardiac Troponin I (cTnI), hematology variables and Prothrombin time (PT) were determined. Systemic inflammation was defined as present if CRP > 35 mg/l.

RESULTS

None of the dogs died during the study period. The mental status was reduced in 60/75 (80%) of dogs on Day 1, compared to 19/75 (25%) on Day 2. The proportion of dogs with no or only mild edema increased significantly from Day 1 to Day 2. About one-third of the dogs developed gastrointestinal signs during the study period. Cardiac arrhythmia was uncommon. Clinicopathological changes included increased total leucocyte count, CRP and troponin concentration on Day 2. The cTnI concentration was increased in dogs with systemic inflammation, compared to dogs without systemic inflammation. A single dose of prednisolone did not significantly affect any of the clinical or clinicopathological parameters studied, except for a higher monocyte count on Day 2 in dogs that had received prednisolone treatment.

CONCLUSION

The results of the present study do not support routine administration of a single dose of prednisolone 1 mg/kg subcutaneously in dogs bitten by Vipera berus.

Safety, potential efficacy, and pharmacokinetics of specific polyclonal immunoglobulin F(ab')₂ fragments against avian influenza A (H5N1) in healthy volunteers: a single-centre, randomised, double-blind, placebo-controlled, phase 1 study

BACKGROUND

Human infection with the avian influenza A H5N1 virus results in disease with a high fatality rate, against which antiviral treatments have limited efficacy. We aimed to investigate the safety, pharmacokinetics, and therapeutic potential of specific polyclonal immunoglobulin equine F(ab')₂ fragments raised against influenza A/Vietnam/1194/2004 virus (H5N1 subtype) in healthy volunteers.

METHODS

We did a randomised, double-blind, placebo-controlled, single-centre phase 1 study. In stage 1 (one infusion) and stage 2 (five infusions) of the trial, we randomly assigned healthy male volunteers to receive once-daily intravenous infusions of 0·85 U/kg body weight of F(ab')₂ or once-daily saline placebo. Randomisation was done centrally, with one block of four patients and one block for substitutes (three actives, one placebo) in stage 1, and two blocks of six patients (five actives and one placebo) and the same block for substitutes in stage 2. The primary objective was assessment of the clinical and laboratory safety of F(ab')₂, which was monitored for 22 days in the group that received one dose (assessments on days 0-2, 4, 8, 15, and 22) and 33 days in the group that received five doses (days 0-6, 8, 10, 12, 19, 26, and 33). A final post-study safety assessment was done at 120 days. We also assessed pharmacokinetic outcomes, and assayed haemagglutination and seroneutralisation activity. Analysis was done according to intention-to-treat. This trial is registered with ClinicalTrials.gov, number NCT02295813.

FINDINGS

We enrolled 16 healthy Asian men between Sept 28 and Dec 28, 2012, and randomly assigned 13 to one or five doses of F(ab')₂ and three to placebo. F(ab')₂ was well tolerated, and no deaths or serious adverse events occurred. Three patients had mild adverse events (one each of blepharospasm, sinusitis, and pyrexia). The pyrexia (38°C) was regarded as probably related to the infusion, and resolved after 37 min. Our laboratory assessments of blood and urine samples and physical examinations of heart rate, electrocardiogram readings, and weight showed no clinically significant safety issues. Mean peak plasma concentrations were 19·3 μg/mL (SD 3·5) with the one dose schedule and 23·0 μg/mL (4·5) with the five-dose schedule. F(ab')₂ were still detectable in plasma on average up to 5 days after five doses. Haemagglutination inhibition was only increased after the third dose, but in-vitro seroneutralisation activity was transiently increased after each of the five doses to concentrations regarded as clinically beneficial in infected patients.

INTERPRETATION

F(ab')₂ showed good safety, tolerability, and therapeutic potential for managing of H5N1 exposed patients.

FUNDING

Fab'entech.

Current treatment for venom-induced consumption coagulopathy resulting from snakebite

Venomous snakebite is considered the single most important cause of human injury from venomous animals worldwide. Coagulopathy is one of the commonest important systemic clinical syndromes and can be complicated by serious and life-threatening haemorrhage. Venom-induced consumption coagulopathy (VICC) is the commonest coagulopathy resulting from snakebite and occurs in envenoming by Viperid snakes, certain elapids, including Australian elapids, and a few Colubrid (rear fang) snakes. Procoagulant toxins activate the clotting pathway, causing a broad range of factor deficiencies depending on the particular procoagulant toxin in the snake venom. Diagnosis and monitoring of coagulopathy is problematic, particularly in resource-poor countries where further research is required to develop more reliable, cheap clotting tests. MEDLINE and EMBASE up to September 2013 were searched to identify clinical studies of snake envenoming with VICC. The UniPort database was searched for coagulant snake toxins. Despite preclinical studies demonstrating antivenom binding toxins (efficacy), there was less evidence to support clinical effectiveness of antivenom for VICC. There were no placebo-controlled trials of antivenom for VICC. There were 25 randomised comparative trials of antivenom for VICC, which compared two different antivenoms (ten studies), three different antivenoms (four), two or three different doses or repeat doses of antivenom (five), heparin treatment and antivenom (five), and intravenous immunoglobulin treatment and antivenom (one). There were 13 studies that compared two groups in which there was no randomisation, including studies with historical controls. There have been numerous observational studies of antivenom in VICC but with no comparison group. Most of the controlled trials were small, did not use the same method for assessing coagulopathy, varied the dose of antivenom, and did not provide complete details of the study design (primary outcomes, randomisation, and allocation concealment). Non-randomised trials including comparison groups without antivenom showed that antivenom was effective for some snakes (e.g., Echis), but not others (e.g., Australasian elapids). Antivenom is the major treatment for VICC, but there is currently little high-quality evidence to support effectiveness. Antivenom is not risk free, and adverse reactions can be quite common and potentially severe. Studies of heparin did not demonstrate it improved outcomes in VICC. Fresh frozen plasma appeared to speed the recovery of coagulopathy and should be considered in bleeding patients.

Immunological cross-reactivity and neutralisation of European viper venoms with the monospecific Vipera berus antivenom ViperaTAb

Medically important cases of snakebite in Europe are predominately caused by European vipers of the genus Vipera. The mainstay of snakebite therapy is polyclonal antibody therapy, referred to as antivenom. Here we investigate the capability of the monospecific V. berus antivenom, ViperaTAb^®, to cross-react with, and neutralise lethality induced by, a variety of European vipers. Using ELISA and immunoblotting, we find that ViperaTAb^® antibodies recognise and bind to the majority of toxic components found in the venoms of the Vipera species tested at comparably high levels to those observed with V. berus. Using in vivo pre-clinical efficacy studies, we demonstrate that ViperaTAb^® effectively neutralises lethality induced by V. berus, V. aspis, V. ammodytes and V. latastei venoms and at much higher levels than those outlined by regulatory pharmacopoeial guidelines. Notably, venom neutralisation was found to be superior to (V. berus, V. aspis and V. latastei), or as equally effective as (V. ammodytes), the monospecific V. ammodytes “Zagreb antivenom”, which has long been successfully used for treating European snake envenomings. This study suggests that ViperaTAb^® may be a valuable therapeutic product for treating snakebite by a variety of European vipers found throughout the continent.