The theory of intraspecies variation is not the exception, but simply the rule: The diverse hemostatic activities of snake venoms

Abstract

Clinical unpredictability of snake envenomation by the same species has been previously illustrated. These symptoms have been well known in the most common genera, Bothrops and Crotalus. Variations between venoms among various geographic regions may be due to evolutionary environmental pressure, which continually acts on separated populations. Studies concerning the disparity of snake venom are fundamental for the understanding of snake phylogeny and most significantly for the investigation and production of suitable antivenoms to treat ophidic envenomation. In the Americas, a geographic intraspecific variation in snake venom composition has been described for Crotalus and Bothrops. Intraspecific venom differences takes place among specific snakes, most likely due to seasonal variation, diet, habitat, age, sexual dimorphism, along with other unidentified factors that could possibly be contributing to the individual variability of venom composition. Furthermore, diverse hemostatic activities of snake venoms differ in their biochemical structure and pharmacological profile, not only between different species, but also within species, and in snakes of diverse ages, sex and geographical localities. Most of these studies scarcely demonstrate the interspecies variation of venoms in specimens from far and near geographical locations, which sustain the need to incorporate pools of venoms of the same species found in different geographical environments that will be employed in immunization protocols for the production of antivenoms.