Methodology/Principal Findings

We carried out an epidemiological survey of snake bites in various regions of France, and the results were published. The analysis of the genes and transcripts encoding venom PLA2s was done in parallel with the genetic analysis. Our research team used SELDI technology to investigate the diversity of PLA2 in various venom specimens. There have been reports of neurological signs (primarily cranial nerve disturbances) following snake bites in three different French regions: Languedoc-Roussillon, Midi-Pyrénées and Provence-Alpes-Côte de d’Azur. The genomes of Vipera aspis snakes from the southeast of France were found to contain ammodytoxin isoforms that had not previously been discovered in the genomes of Vipera aspis snakes from other parts of France. It was discovered that snakes from the Massif Central region had transcripts encoding venom neurotoxic PLA2s, which was a surprise. Thus, SELDI analysis of PLA2 venom composition confirmed the presence of a neurotoxic Vipera aspis snake population in the western part of the Massif Central mountains, which was previously thought to be extinct.

Buy Vipera aspis Venom Online

Conclusions/Significance Combining epidemiological studies with genetic, biochemical, and immunochemical analyses of snake venoms enabled a thorough evaluation of the potential neurotoxicity of snake bites to be made. It has been discovered that there is a relationship between the manifestation of neurological symptoms in humans and the intensity of the cross-reaction of venoms with anti-ammodytoxin antibodies, which is inversely proportional to the level of neurotoxin (vaspin and/or ammodytoxin) expression in the venom. The origin of the two recently discovered neurotoxic snake populations is discussed in light of the venom PLA2 genome and transcriptome data, as well as other available information.

On the French mainland, there are four species of vipers belonging to the genus Vipera. These species have not been linked to the transmission of serious envenomation in either of the cases mentioned above. Both the Basque viper (Vipera seoanei) and the meadow viper (Vipera ursini) are small snakes that live in a small area and are not considered to be dangerous in terms of medical significance. The other two French viper species, the adder (Vipera berus) and the asp viper (Vipera aspis), are larger snakes that can cause life-threatening envenomation if bitten. The adder (Vipera berus) is the smallest of the three and the asp viper (Vipera aspis) is the largest. Because it is adapted to cold climates, Vipera berus can be found in Scandinavian countries that are outside of the Arctic polar circle, including Finland. The northern half of France, as well as the mountainous regions of central France, represent the southernmost extension of the species’ range. It is common in Sweden and England to see this type of snake. Sun and warm temperatures are required for the vipera aspis’s survival, and it can be found primarily in southern France, particularly in the Loire Valley. It has the ability to proliferate in the right conditions. Even within a single population, the pattern markings are highly variable in appearance. Vipera aspis bites occurred in Southeastern France over a 13-year period, and our reporting of the data on these bites should provide clinicians with useful insights into the management of patients envenomed by native Vipera species, including those who suffer neurological toxicity.

Snake venoms are complex mixtures of proteins that have biological activity. They contain a variety of enzymes and toxins that work together to accomplish the two primary functions of the venom, which are to subdue and digest prey respectively. Over the last twenty years, numerous studies have been conducted to document the diversity of snake venom within species. The variation in venom composition that occurs as a result of geographic location is an important aspect of intraspecific variability. Several species of medical importance belonging to the families Viperidae and Elapidae produce a variety of clinical symptoms depending on where they are found in their geographic range of distribution.
The reasons for this variability are still up in the air.
In some cases, the validity of the species definition is required, and the apparent intraspecies variation is actually interspecies variation, and vice versa. A major mechanism of diversification in the composition of snake venoms is thought to be interspecies hybridization, which may be a major cause of this diversification. The diversity of snake venom, regardless of its source, is important both for our understanding of venomous snake evolution and for the preparation of appropriate antivenoms for the treatment of venomous snake envenomations.
In Europe, three species of venomous snakes are considered to be of medical importance: Vipera aspis, Vipera berus, and Vipera ammodytes (Vam). Acute envenomation by the vipers Vipera aspis aspis (VAA) and Vipera berus (Vbb) is characterised by the presence of predominantly local symptoms, which may be accompanied by systemic symptoms (e.g., gastrointestinal and coagulation disorders, low blood pressure) in severe cases.