Treatment Of Snake Bites

Treatment of snake bites by Bothrops species and Lachesis muta in Ecuador: laboratory screening of candidate antivenoms

R. D. G. Theakston a, Corresponding Author Contact Information, G. D. Laing a, C. M. Fielding a, A. Freite Lascano b, J. -M. Touzet c, F. Vallejo d, R. H. Guderian e, S. J. Nelson f, W. Wüster g, A. M. Richards a, J. Rumbea Guzman b and D. A. Warrell h

a Venom Research Unit, Liverpool School of Tropical Medicine, Liverpool, UK
b Instituto Nacional de Higiene y Medicina Tropical, Guayaquil, Ecuador
c Fundacion Herpetologia Gustavo Orces, Quito, Ecuador
d Salud Internacional y Desarrollo, MPH, Quito, Ecuador
e Hospital Vozandes, Quito, Ecuador
f Hospital Vozandes Oriente, Shell Pastaza, Ecuador
g School of Biological Sciences, University of Wales, Bangor, Gwynedd, Wales, UK
h Centre for Tropical Medicine, University of Oxford, Oxford, UK

Received 31 January 1995; Revised 4 April 1995; accepted 10 April 1995. Available online 16 March 2004.


Bothrops xanthogrammus/asper, B. atrox and Lachesis muta are probably responsible for most cases of severe envenoming in Ecuador. In recent years, the most widely used antivenom (‘Myn’ Ronti, imported from Mexico) has proved clinically ineffective. There is an urgent need to identify an effective alternative for clinical testing. Five antivenoms with activity against Bothrops venoms were compared using standard World Health Organization rodent and in vitro assays: (i) ‘Myn’, Ronti Mexico SA (‘B. atrox’, ‘Crotalus terrificus’, (ii) Instituto Butantan (Bothrops polyvalent, Brazil), (iii) Instituto Nacional de Higiene y Medicina Tropical (Bothrops polyvalent, Ecuador), (iv) Instituto Nacional de Salud (B. asper, C. durissus and Lachesis muta, Colombia), and (v) Laboratorios Probiol (Bothrops, Lachesis and Crotalus, Colombia). The venoms against which these antivenoms were tested were Ecuadorian B. atrox, B. asper and B. xanthogrammus. Brazilian antivenom proved to be the most effective, followed by the Ecuadorian and Colombian antivenoms. Mexican antivenom was completely ineffective in neutralizing the lethal effects of Ecuadorian Bothrops venoms. Monospecific Brazilian L. muta antivenom (Instituto Butantan) proved effective against Ecuadorian L. muta venom, but the Colombian polyspecific antivenoms did not. Clinical trials of Brazilian and Ecuadorian antivenoms are planned in the Amazon region of Ecuador in the near future.

Author Keywords: Author Keywords: snake bite; antivenoms; Bothrops spp; Lachesis muta; Ecuador