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.

Venomics of the milos viper (Macrovipera schweizeri) unveils patterns of venom composition and exochemistry across blunt-nosed viper venoms.

Introduction: Snakebite is a neglected tropical disease and a globally important driver of death and morbidity. Vipers of the genus Macrovipera (Viperidae: Viperinae) are among the snakes of higher medical importance in the Old World. Despite the medical relevance of Macrovipera venoms, the knowledge regarding them is heterogeneously distributed with virtually all works conducted so far focusing on subspecies of Macrovipera lebetinus, while other species within the genus are largely overlooked. Here we present the first proteomic evaluation of the venom from the Greek endemic Milos viper (Macrovipera schweizeri). In line with clinical symptoms typically elicited by Macrovipera envenomations, Milos viper venom primarily comprises coagulotoxic and cytotoxic protein families, such as metalloproteinases (svMP) and serine proteases (svSP). Methods: We conducted comparative bioactivity assays on venoms from M. schweizeri and the M. lebetinus subspecies M. lebetinus cernovi, M. lebetinus obtusa, and M. lebetinus turanica, and showed that they all exhibit similarities in levels of cytotoxicity proteolytic activity, and inhibition of prokaryotic growth. Lastly, we compared Macrovipera venom profiles by 1D-SDS-PAGE and RP-HPLC, as well as our proteomic data with previously published Macrovipera venom proteomes. Results and discussion: The analyzes performed to reveal that a general venom profile seems to be conserved across blunt-nosed vipers, and that, M. schweizeri envenomations, similarly to those caused by other blunt-nosed vipers, are able to cause significant tissue damage. The present work represents an important starting point for the development of comparative studies across the full taxonomic range of the genus Macrovipera and can potentially help optimize the treatment of envenomations caused by M. schweizeri.

Venomous Bites, Stings and Poisoning by European Vertebrates as an Overlooked and Emerging Medical Problem: Recognition, Clinical Aspects and Therapeutic Management.

Europe presents a high number of venomous and poisonous animals able to elicit medically relevant symptoms in humans. However, since most of the accidents involving venomous or poisonous animals in Europe are unreported, their incidence and morbidity are severely overlooked. Here we provide an overview of the European vertebrate species of greatest toxicological interest, the clinical manifestations their toxins can cause, and their treatment. We report the clinical symptoms induced by envenomations and poisoning caused by reptiles, fishes, amphibians and mammals in Europe, ranging from mild, local symptoms (e.g., erythema, edema) to systemic and potentially deadly. The present work constitutes a tool for physicians to recognize envenomation/poisoning symptoms caused by the most medically relevant European vertebrates and to decide which approach is the most appropriate to treat them.

One Size Fits All-Venomics of the Iberian Adder (Vipera seoanei, Lataste 1878) Reveals Low Levels of Venom Variation across Its Distributional Range.

European vipers (genus Vipera) are medically important snakes displaying considerable venom variation, occurring at different levels in this group. The presence of intraspecific venom variation, however, remains understudied in several Vipera species. Vipera seoanei is a venomous snake endemic to the northern Iberian Peninsula and south-western France, presenting notable phenotypic variation and inhabiting several diverse habitats across its range. We analysed the venoms of 49 adult specimens of V. seoanei from 20 localities across the species' Iberian distribution. We used a pool of all individual venoms to generate a V. seoanei venom reference proteome, produced SDS-PAGE profiles of all venom samples, and visualised patterns of variation using NMDS. By applying linear regression, we then assessed presence and nature of venom variation between localities, and investigated the effect of 14 predictors (biological, eco-geographic, genetic) on its occurrence. The venom comprised at least 12 different toxin families, of which five (i.e., PLA2, svSP, DI, snaclec, svMP) accounted for about 75% of the whole proteome. The comparative analyses of the SDS-PAGE venom profiles showed them to be remarkably similar across the sampled localities, suggesting low geographic variability. The regression analyses suggested significant effects of biological and habitat predictors on the little variation we detected across the analysed V. seoanei venoms. Other factors were also significantly associated with the presence/absence of individual bands in the SDS-PAGE profiles. The low levels of venom variability we detected within V. seoanei might be the result of a recent population expansion, or of processes other than directional positive selection.

Toxic Habits: An Analysis of General Trends and Biases in Snake Venom Research.

Biases in snake venom research have been partially identified but seldomly quantified. Using the Google Scholar web search engine, we collected a total of 267 articles published between 1964 and 2021, and reviewed them to assess the main trends in this field of study. We developed a 4-category classification of the harmful potential of each of the 298 snake species retrieved from the analysed publications, and tested whether taxonomy, realm of origin, and/or assigned hazard category could affect how often each of them appeared in the articles considered. Overall, viperids were significantly more represented than any other snake taxon retrieved. The Neotropics were the most represented biogeographic realm for number of studied species, whereas information about the country of origin of the analysed specimens was often incomplete. The vast majority of the publications focused on snake venom characterisation, whereas more ecology-related topics were rarely considered. Hazard category and biogeographic realm of origin of each species had a significant effect on the number of articles dedicated to it, suggesting that a snake's harmful potential and place of origin influence its popularity in venom studies. Our analysis showed an overall positive trend in the number of snake venom studies published yearly, but also underlined severe neglect of snake families of supposedly minor medical relevance (e.g., Atractaspididae), underrepresentation of some of the areas most impacted by snakebite (i.e., Indomalayan and Afrotropic realms), and limited interest in the ecological and functional context of snake venom.

Interpopulational variation and ontogenetic shift in the venom composition of Lataste's viper (Vipera latastei, Boscá 1878) from northern Portugal.

Lataste's viper (Vipera latastei) is a venomous European viper endemic to the Iberian Peninsula, recognised as medically important by the World Health Organization. To date, no comprehensive characterisation of this species' venom has been reported. Here, we analysed the venoms of juvenile and adult specimens of V. latastei from two environmentally different populations from northern Portugal. Using bottom-up venomics, we produced six venom proteomes (three per population) from vipers belonging to both age classes (i.e., two juveniles and four adults), and RP-HPLC profiles of 54 venoms collected from wild specimens. Venoms from juveniles and adults differed in their chromatographic profiles and relative abundances of their toxins, suggesting the occurrence of ontogenetic changes in venom composition. Specifically, snake venom metalloproteinase (SVMP) was the most abundant toxin family in juvenile venoms, while snake venom serine proteinases (SVSPs), phospholipases A2 (PLA2s), and C-type lectin-like (CTLs) proteins were the main toxins comprising adult venoms. The RP-HPLC venom profiles were found to vary significantly between the two sampled localities, indicating geographic variability. Furthermore, the presence/absence of certain peaks in the venom chromatographic profiles appeared to be significantly correlated also to factors like body size and sex of the vipers. Our findings show that V. latastei venom is a variable phenotype. The intraspecific differences we detected in its composition likely mirror changes in the feeding ecology of this species, taking place during different life stages and under different environmental pressures. SIGNIFICANCE: Lataste's viper (Vipera latastei) is a medically important viper endemic to the Iberian Peninsula, inhabiting different habitats and undergoing a marked ontogenetic dietary shift. In the current study, we report the first proteomic analysis of V. latastei venom from two environmentally different localities in northern Portugal. Our bottom-up venomic analyses show that snake venom serine proteinases (SVSPs), phospholipases A2 (PLA2s), and C-type lectin-like (CTLs) proteins are the major components of adult V. latastei venom. The comparative analysis of young and adult venoms suggests the occurrence of ontogenetic shift in toxin abundances, with snake venom metalloproteinases (SVMPs) being the predominant toxins in juvenile venoms. Moreover, geographic venom variation between the two studied populations is also detected, with our statistical analyses suggesting that factors like body size and sex of the vipers are possibly at play in its determination. Our work represents the first assessment of the composition of V. latastei venom, and the first step towards a better understanding of the drivers behind its variability.

Unexpected lack of specialisation in the flow properties of spitting cobra venom.

Venom spitting is a defence mechanism based on airborne venom delivery used by a number of different African and Asian elapid snake species ('spitting cobras'; Naja spp. and Hemachatus spp.). Adaptations underpinning venom spitting have been studied extensively at both behavioural and morphological level in cobras, but the role of the physical properties of venom itself in its effective projection remains largely unstudied. We hereby provide the first comparative study of the physical properties of venom in spitting and non-spitting cobras. We measured the viscosity, protein concentration and pH of the venom of 13 cobra species of the genus Naja from Africa and Asia, alongside the spitting elapid Hemachatus haemachatus and the non-spitting viper Bitis arietans. By using published microCT scans, we calculated the pressure required to eject venom through the fangs of a spitting and a non-spitting cobra. Despite the differences in the modes of venom delivery, we found no significant differences between spitters and non-spitters in the rheological and physical properties of the studied venoms. Furthermore, all analysed venoms showed a Newtonian flow behaviour, in contrast to previous reports. Although our results imply that the evolution of venom spitting did not significantly affect venom viscosity, our models of fang pressure suggests that the pressure requirements to eject venom are lower in spitting cobras than in non-spitting cobras.

Unexpected lack of specialisation in the flow properties of spitting cobra venom.

Venom spitting is a defence mechanism based on airborne venom delivery used by a number of different African and Asian elapid snake species ('spitting cobras'; Naja spp. and Hemachatus spp.). Adaptations underpinning venom spitting have been studied extensively at both behavioural and morphological level in cobras, but the role of the physical properties of venom itself in its effective projection remains largely unstudied. We hereby provide the first comparative study of the physical properties of venom in spitting and non-spitting cobras. We measured the viscosity, protein concentration and pH of the venom of 13 cobra species of the genus Naja from Africa and Asia, alongside the spitting elapid Hemachatus haemachatus and the non-spitting viper Bitis arietans By using published microCT scans, we calculated the pressure required to eject venom through the fangs of a spitting and a non-spitting cobra. Despite the differences in the modes of venom delivery, we found no significant differences between spitters and non-spitters in the rheological and physical properties of the studied venoms. Furthermore, all analysed venoms showed a Newtonian flow behaviour, in contrast to previous reports. Although our results imply that the evolution of venom spitting did not significantly affect venom viscosity, our models of fang pressure suggests that the pressure requirements to eject venom are lower in spitting cobras than in non-spitting cobras.

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.