Mexican coral snake venoms, their potent neurotoxins, and how to neutralize them.

Coral snakes are the most diversified group of Elapids in The Americas. All of them possess a highly neurotoxic venom that they use to paralyze and presumably predigest their prey, which consists of small snakes and lizards. In relatively few cases (less than 5% of snakebites on the continent), these secretive animals bite humans and inject venom, causing a clinical syndrome characterized by progressive flaccid paralysis.

Probably due to this low incidence of human envenomations, venoms from Mexican coral snakes remained completely unstudied until about 15 years ago, leaving a gap in the knowledge that included almost all North American species. Here, we present an overview of the recent research on their venom composition, focused on the identification of toxins that are relevant during human envenomation and the ability of antivenoms to neutralize them.

We then show the first conclusive evidence of individual variation within these venoms, using as a study model the Balsas Coral Snake (Micrurus laticollaris), and demonstrate that such variation affects their neutralization by antivenoms. Finally, we propose a strategy for current antivenom improvement and test its viability using experimental hyperimmune sera.