Bites and envenomations by colubrid snakes in Mexico and Central America

Information on bites by snakes of the family Colubridae in Mexico and Central America is reviewed. Little is known of the biochemistry and pharmacology of the Duvernoy gland secretion (venom) of colubrids from this region, although some reports describe proteolytic, phosphodiesterase, phospholipase A(2) and hemorrhagic activities. A search of published reports and an effort to obtain reliable unpublished information on colubrid snake bites in the region documented cases inflicted by species of the genera Conophis, Coniophanes, Crisantophis, Etythrolamprus, Pliocercus, Oxybelis and Dqadophis (=Mastigodryas). The following general pattern emerges from the analysis of these cases: 1) Bites occurred mainly in hands and ringers on people that frequently manipulate colubrids, i.e. herpetologists, herpetoculturists and people that take care of these snakes at museums, exhibits or zoos; and 2) In most cases, only mild local effects were described, i.e. pain, swelling and, in few cases, ecchymosis. In only one case by Erythrolamprus bizonus there was ecchymosis beyond the bitten region, whereas persistent bleeding at the bite site was reported in a Conophis lineatus case. No systemic alterations were described in any of the cases. Management of colubrid bites in Mexico and Central America includes cleaning and disinfection of the bitten area, together with administration of tetanus toxoid. In the case of local infection, antibiotics are administered. There is no experimental or clinical evidence supporting the use of Crotalinae antivenoms in these bites. Despite the lack of systemic alterations in the cases described, caution should be exercised when manipulating these snakes, and bitten people should be closely observed for the potential development of bleeding and coagulopathies, since these effects have been described in bites by colubrid snakes from other regions of the world.