Neutralization of two North American coral snake venoms with United States and Mexican antivenoms

Abstract

Elapid snakes throughout the world are considered very lethal, containing neurotoxic venoms that affect the nervous system. When humans are envenomated it is considered a serious medical emergency, and antivenom is the main form of treatment considered, in spite of the fact that some patients may only survive under intensive therapy treatment such as respiratory support. Coral snakes are part of the family Elapidae and envenomations by these snakes are very low (<2% of total snakebites) in most countries from southeastern United States to Argentina. In the United States, there are only two species of coral snakes of medical importance that belong to the Micrurus genera: Micrurus fulvius fulvius (Eastern coral snake) and Micrurus tener tener (Texas coral snake). In 2006, Wyeth pharmaceutical notified customers that the production of the North American coral snake antivenin (NACSA) in the US was discontinued and adequate supplies were available to meet historical needs through the end of October 2008; and therefore, it is of utmost important to consider other antivenoms as alternatives for the treatment of coral snake envenoming. One logical alternative is the coral snake antivenom, Coralmyn, produced by the Mexican company, Bioclon. In order to compare neutralization between NACSA and Coralmyn antivenoms with the North American coral snake venoms, the venom lethal doses (LD(50)) and antivenom effective doses (ED(50)) were determined in 18-20 g, female, BALB/c mice. Additionally, venom comparisons were determined through a non-reduced SDS-PAGE for M.f.fulvius, M.t.tener and the Mexican coral snake venom, Micrurus nigrocinctus nigrocinctus. Coralmyn antivenom was able to effectively neutralize three LD(50) doses of all venom from both M.t.tener and M.f.fulvius, while Wyeth antivenom only neutralized M.f.fulvius venom and was not effective in neutralizing three LD(50) doses of M.t.tener venom. Coralmyn is effective in the neutralization of both clinically important coral snake venoms in the US.

Figure 1

Geographical distribution of Micrurus fulvius fulvius and M. tener tener.

Figure 2

Non-reduced SDS PAGE of Micrurus venoms. A 10–20% Tris-Glycine gel was used to run 6 µg of M. t. tener venoms pools I and II, M. f. fulvius venoms pools I and II and M. n. nigrocinctus venom. An XCell SureLock™ electrophoresis system with Tris-Glycine SDS running buffer was used. The gel was run at 130V, 90 min on a Bio-Rad PowerPac™ Basic. The markers used were SeeBlue Plus2 (Invitrogen). Mtt: M. t. tener, Mff: M. f. fulvius, and Mnn: M. n. nigrocinctus.