Search Results (64)

Snakebite envenoming remains a critical public health issue, and the molecular variability of venoms limits the cross-species efficacy of conventional antivenoms. Here, we conducted a comparative proteomic analysis of Bitis arietans venom to identify conserved peptide regions derived from enzymatic toxins and evaluate their potential relevance for complementary immunotherapeutic applications. Enzyme-enriched venom fractions were isolated through sequential affinity and ion-exchange chromatography and were subsequently characterized using fluorogenic FRET substrates and inhibitor assays. LC–MS/MS analysis identified 1099 proteins and revealed 36 conserved peptides within snake venom metalloproteinases (SVMPs), serine proteases (SVSPs), and phospholipase A₂ (PLA₂), particularly located near catalytic residues and structurally essential motifs such as the HExxHxxGxxH zinc-binding site in SVMPs, the His-Asp-Ser catalytic triad in SVSPs, and the Ca²⁺-binding loop in PLA₂, across Viperidae venoms. These conserved regions were also observed in homologous toxin isoforms from additional Viperidae genera, supporting the evolutionary conservation of key functional domains. While sequence conservation alone does not guarantee neutralization capacity, the identified regions represent strong candidates for structural epitope mapping and targeted antibody development. This study provides a peptide-level framework for advancing complementary antibody-based therapies designed to broaden cross-species toxin recognition, reduce antivenom dosage requirements, and improve clinical outcomes in snakebite envenoming. Full article

The saw-scaled viper Echis carinatus, one of the “Big Four” causes of snakebites in India, is found from Sri Lanka to eastern Iraq. To investigate clinical reports regarding the limited efficacy of Indian polyvalent antivenom (IPAV) against envenomation in Echis carinatus sochureki (ECS) in northwestern India, we obtained 22 snakes from three locations in Rajasthan and identified 148–174 toxin isoforms belonging to 21–25 toxin families in their venom using a bottom-up proteomics approach. All samples showed a high abundance of snake venom metalloproteinases (SVMPs), particularly SVMP class III. Other major components were phospholipases A₂, L-amino-acid oxidases, snake venom serine proteases and snaclecs (C-type lectins). Variation in venom composition among locations in Rajasthan, compared to E. c. carinatus (ECC) from southern India, was primarily due to differences in the relative abundance of these toxin families. Recognition of all venom components by IPAV was poor at lower antivenom concentrations. Notably, SVMP classes II and III were poorly recognized at all venom-to-antivenom ratios in all ECS venoms, and a plasma clotting assay revealed poor neutralization of procoagulant activity. This collaborative study highlights the need for the development of regional antivenoms to effectively treat snakebites in northwestern India. Full article

Background/Objectives: Snakebite envenoming remains a critical yet frequently under-recognized cause of mortality in many parts of the world, particularly in tropical and rural areas where access to timely medical care and accurate post-mortem investigation is limited. While clinical and epidemiological data on snakebites have been extensively studied, the forensic characterization of fatal envenomations remains fragmentary and inconsistently documented. This review aims to synthesize the existing literature on autopsy-confirmed snakebite deaths, focusing on the pathological and toxicological evidence that supports cause-of-death determinations in forensic settings. Methods: A comprehensive search of the PubMed NCBI databases identified nine relevant studies, including case reports, retrospective analyses, and systematic reviews. Results: Across these reports, a range of lethal mechanisms were identified, including venom-induced consumption coagulopathy (VICC), acute renal failure (frequently in the setting of rhabdomyolysis and acute tubular necrosis), neurotoxic respiratory arrest, multi-organ necrosis, and myocardial infarction. Histological findings frequently revealed glomerular and tubular necrosis, pulmonary edema and/or hemorrhage, pituitary and adrenal hemorrhage, and cerebral ischemic changes. Toxicological confirmation was achieved in several cases using ELISA and liquid chromatography–mass spectrometry (LC–MS/MS), underscoring the importance of biochemical validation in post-mortem diagnosis and the value of analytical tools beyond ELISA (e.g., immunoaffinity LC–MS/MS, venom-specific immunohistochemistry, zymography for SVMP activity). Conclusions: Our findings highlight the variability in venom effects across snake families—particularly Viperidae, Elapidae, and Lamprophiidae/Atractaspididae—and emphasize the indispensable role of forensic autopsy in distinguishing snakebite envenoming from other causes of sudden or unexplained death. However, significant limitations persist, including inconsistent autopsy protocols, lack of species-specific venom assays, and poor integration of toxicological methods in routine forensic practice. Addressing these gaps through standardized forensic guidelines and improved access to diagnostic tools is essential for enhancing the accuracy of death investigations in envenoming-endemic regions. Full article

Species diversity within the green pit vipers of the genus Trimeresurus is likely underestimated. In this study, we describe a new species of Trimeresurus from the Xizang Autonomous Region, China, based on both morphological and molecular evidence. The new species, Trimeresurus pretiosus sp. nov., is assigned to the subgenus Viridovipera Malhotra Thorpe. It is distinguished from its congeners by the following combination of morphological characters: (1) first supralabial completely separated from nasal scale; (2) hemipenis short and spinose, reaching the 12th subcaudal when fully everted; (3) small adult size, with a maximum known snout-vent length of 516 mm in males and 512 mm in females; (4) dorsal scales in 19–19–15 rows, weakly keeled except for the outermost rows; (5) 140–143 ventral scales; (6) 56–58 subcaudal scales in males and 54 in females, partially arranged in a single row; (7) iris reddish-brown in males, orange-yellow in females; (8) body uniformly bright grass-green; postocular streak absent or faint white in males, absent in females; (9) ventrolateral stripe consisting of red above and white below and wide in males, only white and narrow in females; (10) ventral surfaces greenish-yellow; (11) tail distinctly reddish-brown dorsally, with the colouration extending from tail base to tip. Molecular analyses based on the mitochondrial 16S, cyt b, and ND4 gene fragments indicate that the new species is genetically divergent from all congeners, with uncorrected p-distances ranging from 5.8% to 12.5% in the cyt b gene and from 6.7% to 11.0% in the ND4 gene. The new species is currently known only from the southern slopes of the central Himalayas in Yadong County, and it represents the second known Viridovipera species from the southern Himalayas. With this discovery, the total number of snake species known from the Xizang Autonomous Region increases to 67, underscoring the importance of continued herpetofaunal surveys in this biogeographically complex region. Full article

A review was conducted on snakebites in Central America. Information was extracted using the databases of PubMed, SciELO, and LILACS. Information included retrospective studies, case reports, and case series; in this way, valuable information was retrieved from limited sources. The identified studies comprised those discussing envenoming snakebites. Several species were identified, but three of them had major epidemiological features impacting envenoming by snakebites: Bothrops asper, Crotalus simus, and Micrurus sp. Adolescents and young adult males living in rural areas and engaged in agricultural activities were identified as the main victims of snakebites by clinical records. Symptoms of local damage in the bite sites included edema and skin and muscle necrosis. In addition, the cardiovascular system was affected, with symptoms like hypotension, bleeding, and coagulation disorders. Neurotoxicity causing sensitivity and motricity problems was also reported. For El Salvador, accidents caused by Crotalus simus and Micrurus spp. were given more attention due to their greater relevance. The role of Bothrops species was more relevant in the envenoming reported by other countries. Treatment was found to be provided based on antivenoms produced in Costa Rica, and the recovery of the patients depended on the time elapsed between the accident and the initial treatment in the healthcare system. Full article

Snakebite envenoming constitutes a significant global health issue, particularly in Africa, where venomous species such as Echis vipers and Dendroaspis mambas pose substantial risks to human health. This study employs a standardized venomics workflow to comprehensively characterize and comparatively quantify the venom composition of nine medically relevant snake species chosen from among the deadliest in Africa. Utilizing shotgun venom proteomics and venom gland transcriptomics, we report detailed profiles of venom complexity, highlighting the relative abundance of dominant toxin families such as three-finger toxins and Kunitz-type proteins in Dendroaspis, and metalloproteinases and phospholipases A₂ in Echis. We delineate here the relative abundance and structural diversity of venom components. Key to our proteomic approach is the implementation of Multi-Enzymatic Limited Digestion (MELD), which improved protein sequence coverage and enabled the identification of rare toxin families such as hyaluronidases and renin-like proteases, by multiplying the overlap of generated peptides and enhancing the characterization of both toxin and non-toxin components within the venoms. The culmination of these efforts resulted in the construction of a detailed toxin database, providing insights into the biological roles and potential therapeutic targets of venom proteins and peptides. The findings here compellingly validate the MELD technique, reinforcing its reproducibility as a valuable characterization approach applied to venomics. This research significantly advances our understanding of venom complexity in African snake species, including representatives of both Viperidae and Elapidae families. By elucidating venom composition and toxin profiles, our study paves the way for the development of targeted therapies aimed at mitigating the morbidity and mortality associated with snakebite envenoming globally. Full article

Snakes are stimuli inducing an ancestral fear response in humans and other primates. Certain snakes evoke more subjective fear than others. True vipers are high-fear-eliciting snakes for both African and European respondents. This can be explained by the evolutionary experience of human ancestors in Africa. The question arises as to how snakes living in the Americas and Australia, with which humans have no evolutionary experience, will be evaluated. While these snakes belong to broader taxonomic groups that have distant relatives in the Old World, they have evolved independently for tens of millions of years. We prepared a set of 32 pictures depicting eight American pit vipers, eight Australian elapids, eight constrictors, and eight colubrids and asked the respondents to rank these stimuli according to the fear these snakes evoke. Here, we show a high cross-cultural agreement between evaluations by African and European respondents. Snakes characterized by a robust body shape, such as American pit vipers, Australian death adders, pythons, and boas, were the most fear-evoking. The body width was the strongest predictor of evoked fear. The contribution of coloration and pattern of the stimulus to the fear response was not proved. This supports the view that the patterns of fear are not dependent on direct experience, but its underlying mechanisms are shared cross-culturally. Full article

Doñana (southern Spain), a region of notable biodiversity richness, is highly threatened by ongoing landscape transformation and climate change. We investigated the local effect of these anthropogenic factors on the temporal range dynamics of Lataste’s viper (Vipera latastei), an Iberian endemic Mediterranean reptile that has apparently become rare over the years in Doñana. Using ecological niche-based models, based on climatic and remote sensing variables, we analyzed historical (1959–1999) and contemporary (2000–2022) records of the species to assess range shifts and identify environmental factors that may influence them. Our results show that V. latastei is mostly restricted to the coastal region of Doñana and that one temperature variable is the most important factor explaining this distribution pattern in both periods. Additional climatic and vegetation variables play a role in its historical distribution, but they become less important in contemporary times, suggesting a niche simplification over time. We found 30.5% of reduction in the species suitable area from historical to contemporary conditions, a reduction that would be even greater (83.37%) in the absence of niche shift. These findings underscore the species’ heightened vulnerability to ongoing environmental changes and highlight the urgent need for targeted conservation strategies. Full article

Viruses in the subfamily Serpentovirinae (order Nidovirales, family Tobaniviridae) can cause significant morbidity and mortality in captive snakes, but documented infections have been limited to snakes of the Boidae, Colubridae, Homalopsidae, and Pythonidae families. Infections can either be subclinical or associated with oral and/or respiratory disease. Beginning in June 2019, a population of over 150 confiscated snakes was screened for serpentovirus as part of a quarantine disease investigation. Antemortem oropharyngeal swabs or lung tissue collected postmortem were screened for serpentovirus by PCR, and 92/165 (56.0%) of snakes tested were positive for serpentovirus. Serpentoviruses were detected in fourteen species of Viperidae native to Asia, Africa, and South America and a single species of Elapidae native to Australia. When present, clinical signs included thin body condition, abnormal behavior or breathing, stomatitis, and/or mortality. Postmortem findings included variably severe inflammation, necrosis, and/or epithelial proliferation throughout the respiratory and upper gastrointestinal tracts. Genetic characterization of the detected serpentoviruses identified four unique viral clades phylogenetically distinct from recognized serpentovirus genera. Pairwise uncorrected distance analysis supported the phylogenetic analysis and indicated that the viper serpentoviruses likely represent the first members of a novel genus in the subfamily Serpentovirinae. The reported findings represent the first documentation of serpentoviruses in venomous snakes (Viperidae and Elapidae), greatly expanding the susceptible host range for these viruses and highlighting the importance of serpentovirus screening in all captive snake populations. Full article

Worldwide, it is estimated that there are 1.8 to 2.7 million cases of envenoming caused by snakebites. Snake venom is a complex mixture of protein toxins, lipids, small molecules, and salts, with the proteins typically responsible for causing pathology in snakebite victims. For their chemical characterization and identification, analytical methods are required. Reversed-phase liquid chromatography coupled with electrospray ionization mass spectrometry (RP-LC-ESI-MS) is a widely used technique due to its ease of use, sensitivity, and ability to be directly coupled after LC separation. This method allows for the efficient separation of complex mixtures and sensitive detection of analytes. On the other hand, matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is also sometimes used, and though it typically requires additional sample preparation steps, it offers desirable suitability for the analysis of larger biomolecules. In this study, seven medically important viperid snake venoms were separated into their respective venom toxins and measured by ESI-MS. In parallel, using nanofractionation analytics, post-column high-resolution fractionation was used to collect the eluting toxins for further processing for MALDI-MS analysis. Our comparative results showed that the deconvoluted snake venom toxin masses were observed with good sensitivity from both ESI-MS and MALDI-MS approaches and presented overlap in the toxin masses recovered (between 25% and 57%, depending on the venom analyzed). The mass range of the toxins detected in high abundance was between 4 and 28 kDa. In total, 39 masses were found in both the ESI-MS and/or MALDI-MS analyses, with most being between 5 and 9 kDa (46%), 13 and 15 kDa (38%), and 24 and 28 kDa (13%) in size. Next to the post-column MS analyses, additional coagulation bioassaying was performed to demonstrate the parallel post-column assessment of venom activity in the workflow. Most nanofractionated venoms exhibited anticoagulant activity, with three venoms additionally exhibiting toxins with clear procoagulant activity (Bothrops asper, Crotalus atrox, and Daboia russelii) observed post-column. The results of this study highlight the complementarity of ESI-MS and MALDI-MS approaches for characterizing snake venom toxins and provide a complementary overview of defined toxin masses found in a diversity of viper snake venoms. Full article

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. Full article

Kunitz-type peptide expression has been described in the venom of snakes of the Viperidae, Elapidae and Colubridae families. This work aimed to identify these peptides in the venom gland transcriptome of the coral snake Micrurus mipartitus. Transcriptomic analysis revealed a high diversity of venom-associated Kunitz serine protease inhibitor proteins (KSPIs). A total of eight copies of KSPIs were predicted and grouped into four distinctive types, including short KSPI, long KSPI, Kunitz–Waprin (Ku-WAP) proteins, and a multi-domain Kunitz-type protein. From these, one short KSPI showed high identity with Micrurus tener and Austrelaps superbus. The long KSPI group exhibited similarity within the Micrurus genus and showed homology with various elapid snakes and even with the colubrid Pantherophis guttatus. A third group suggested the presence of Kunitz domains in addition to a whey-acidic-protein-type four-disulfide core domain. Finally, the fourth group corresponded to a transcript copy with a putative 511 amino acid protein, formerly annotated as KSPI, which UniProt classified as SPINT1. In conclusion, this study showed the diversity of Kunitz-type proteins expressed in the venom gland transcriptome of M. mipartitus. Full article

Island tameness results largely from a lack of natural predators. Because some insular rattlesnake populations lack functional rattles, presumably the consequence of relaxed selection from reduced predation, we hypothesized that the Santa Catalina Island, California, USA, population of the southern Pacific rattlesnake (Crotalus helleri, which possesses a functional rattle), would exhibit a decrement in defensive behavior relative to their mainland counterparts. Contrary to our prediction, rattlesnakes from the island not only lacked tameness compared to mainland snakes, but instead exhibited measurably greater levels of defensiveness. Island snakes attempted to bite 4.7 times more frequently as we endeavored to secure them by hand, and required 2.1-fold more time to be pinned and captured. When induced to bite a beaker after being grasped, the island snakes also delivered 2.1-fold greater quantities of venom when controlling for body size. The additional venom resulted from 2.1-fold larger pulses of venom ejected from the fangs. We found no effects of duration in captivity (2–36 months), which suggests an absence of long-term habituation of antipredator behaviors. Breeding bird surveys and Christmas bird counts indicated reduced population densities of avian predators on Catalina compared to the mainland. However, historical estimates confirmed that populations of foxes and introduced mammalian predators (cats and pigs) and antagonists (herbivorous ungulates) substantially exceeded those on the mainland in recent centuries, and therefore best explain the paradoxically exaggerated defensive behaviors exhibited by Catalina’s rattlesnakes. These findings augment our understanding of anthropogenic effects on the behaviors of island animals and underscore how these effects can negatively affect human safety. Full article

Central America is home to one of the most abundant herpetofauna in the Americas, occupying only 7% of the continent’s total area. Vipers and lizards are among the most relevant venomous animals in medical practice due to the consequences of envenomation from the bite of these animals. A great diversity of biomolecules with immense therapeutic and biotechnological value is contained in their venom. This paper describes the prominent leading representatives of the family Viperidae, emphasizing their morphology, distribution, habitat, feeding, and venom composition, as well as the biotechnological application of some isolated components from the venom of the animals from these families, focusing on molecules with potential anti-thrombotic action. We present the leading protein families that interfere with blood clotting, platelet activity, or the endothelium pro-thrombotic profile. In conclusion, Central America is an endemic region of venomous animals that can provide many molecules for biotechnological applications. Full article

Snakes contain three types of phospholipase A₂ (PLA₂)-inhibitory proteins in their blood, PLIα, β, and γ, which protect them from their own venom, PLA₂. PLIβ is the snake ortholog of leucine-rich α₂ glycoprotein (LRG). Since autologous cytochrome c (Cyt c) serves as an endogenous ligand for LRG, in this study, we purified snake LRGs from various snake serum samples using Cyt c affinity chromatography. All purified snake LRGs were found to be dimers linked by disulfide bonds. Laticauda semifasciata and Naja kaouthia LRGs showed no inhibitory activity against L. semifasciata PLA₂ and weak inhibitory activity against Gloydius brevicauda basic PLA₂. Elaphe climacophora PLIβ had weaker inhibitory activity against G. brevicauda basic PLA₂ than G. brevicauda and Elaphe quadrivirgata PLIs, which are abundant in blood and known to neutralize G. brevicauda basic PLA₂. Protobothrops flavoviridis LRG showed no inhibitory activity against basic venom PLA₂, PL-X, or G. brevicauda basic PLA₂. Binding analysis of P. flavoviridis LRG using surface plasmon resonance showed very strong binding to snake Cyt c, followed by that to horse Cyt c, weak binding to yeast Cyt c, and no binding to P. flavoviridis PL-X or BPI/II. We also deduced the amino acid sequences of L. semifasciata and P. flavoviridis LRG by means of cDNA sequencing and compared them with those of other known sequences of PLIs and LRGs. This study concluded that snake LRG can potentially inhibit basic PLA₂, but, whether it actually functions as a PLA₂-inhibitory protein, PLIβ, depends on the snake. Full article