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

Abstract

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 Hygiene 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 Ecudorian 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.

Crotaline snake bite in the Ecuadorian Amazon: randomised double blind comparative trial of three South American polyspecific antivenoms

“…In an earlier preclinical laboratory study, the neutralising potency of five antivenoms (Brazilian, Ecuadorian, Mexican, and two Colombian) was tested against the venoms of B atrox, B asper , and B xanthogrammus 5 6. The Brazilian antivenom proved most effective, followed by the Ecuadorian and two Colombian antivenoms.…”

Estimating geographic patterns of ophidism risk in Ecuador

“…A good predictive performance was observed in potential distribution models for almost all venomous snakes, including those of medical importance such as Bothrops asper, B. atrox, B. brazili, Bothrocophias microphthalmus, Bothriopsis bilineata, B. taeniata, Lachesis muta [4,22,23], except Micrurus dumerilii.…”

“…Of these communities, 75% are located in the western region of Ecuador, 14% in the central region, and 11% in the eastern region. In the latter, our model estimates an extensive area with high snakebite risk values, [22], Theakston et al [23], Praba-Egge et al [25]) and the more comprehensive ones do not provide enough spatial details (e.g. González-Andrade and Chippaux [2]).…”

“…classified as potential distribution for each species. Then, we multiplied these values by the reported proportion of snakebites caused for each species (Table 2) in epidemiological studies carried out in Ecuador [21][22][23]. Finally, we identified vulnerable rural communities (rural localities with high population density and high snakebite risk) based on the "estimates of rural population density to 2015" global raster [24], and a shapefile of localities obtained from "Geodescargas" (http://www.…”

Merit and Demerit of Polyvalent Snake Antivenoms

“…The following examples emphasize this point. Theakston et al (1995) studied 5 pAVs and 1 mAV prepared by different manufacturers and found vast differences in their neutralizing potencies against venoms of Bothrops species and Lachesis muta. Similar observations were made on 4 pAV's anti-Bothrops prepared by different manufacturers from 4 countries (Bogarin et al, 1995).…”