Toxoids and Antivenoms of Venomous Snakes in Taiwan

Abstract

There are in Taiwan six major venomous snakes which can inflict severe bite on human victims. They are three hemorrhagic species i.e. the Taiwan habu (Trimeresurus mucrosquamatus), the green tree viper (Trimeresurus stejnegeri), and the hundred-pace snake (Deinagkistrodon acutus); two neurotoxic species, i.e. the cobra (Naja naja atra) and the krait (Bungarus multicinctus); and the Russell's viper (Daboia r. formosensis) whose venom is both coagulopathy and neurotoxic. Our aim has been the production of highly potent antivenoms for snake-bite treatment in this country. Among individual antivenoms for Taiwan venomous snakes, only those from the pitvipers show partial cross-neutralizing capacity with venoms of other pit vipers.

As all snake venoms are quite lethal to animals, it is important to tame or detoxify the crude venom before using it on the animal to obtain antivenoms. We have demonstrated that glutaraldehyde can be used successfully not only in the detoxification of snake venoms but also improving their immunogenecity. Protocols for toxoid preparation from the crude venoms in the process of manufacturing highly potent antisera have been improved in our institute. Two bivalent equine antivenoms specific for either the combined glutaraldehyde-treated venoms of N. n. atra and B. multicinctus or those of T. mucrosquamatus and T. stejnegeri were successfully produced and proven to be effective and useful. A tetravalent equine antivenom has been prepared likewise against the four major viperid venoms in Taiwan. Recently, we also developed a process to prepare an efficient hexavalent antivenom against all the six major venomous snakes.