Biology and Distribution of Venomous Snakes of Medical Importance and The Composition of Snake Venoms

This chapter deals with venomous snakes, the composition and mode of action of snake venoms, their distribution and some more general aspects of snake biology. Snakes are usually called venomous, when envenomations or human fatalities after their bites are known. Since the members of the Elapidae, Viperidae and Atractaspididae snake families all possess a venom apparatus able to produce and efficiently inject venom, they are also referred to as genuinely venomous snakes. Snakes of medical importance are found in temperate, but predominantly in tropical areas throughout the world. An efficient venom apparatus consists of two parts: a pair of glands for the production of toxic substances, and modified teeth, the so-called fangs as a means to deliver it. Venoms, especially of elapid snakes, lead predominantly to neurotoxic manifestation in both prey animals and human bite victims. Circulatory shock is the main cause of death following viper and pit viper bites.