New Approaches in Antivenom Therapy

Abstract

Snake bites are a major public health problem throughout the world, particularly in tropical countries where mortality and morbidity rates are very high. The specific treatment of ophidian envenomation is serotherapy. It consists in the empirical administration of large amounts of specific antivenoms. Although serotherapy has been discovered a century ago, the mechanism by which antibodies of antivenoms neutralize venom proteins in vivo is still poorly understood. In order to rationalize antivenom therapy, clinicians should be able to know as quickly as possible the severity of the envenomation, to assess the appropriateness of serotherapy and to adapt the dose of serum to inject to the gravity of envenoming. Moreover, some parameters of antivenom administration such as the delay in administration after snake bites, and the route of injection and the type of antibodies to be used, are dependent on the understanding of the kinetics of venom and antivenom. Such investigations have been performed in the case of envenomations by European vipers in France. An ELISA was developed to determine venom concentrations in biological samples of patients bitten by vipers in an attempt to establish a correlation between venom levels and clinical symptoms. The kinetics of Vipera aspis venom was studied using experimental envenomations in rabbits. The effect of antivenom administration on the toxicokinetics of venom was also determined.