title: The efficacy of two antivenoms against the venom of North American snakes.
abstract: Mortality due to snake envenomation is not a major problem in the United States with approximately 8-12 deaths per year, but envenomation is a serious problem that can result in functional disability, loss of extremities, and a costly recovery. Physicians encounter different clinical situations with each new snakebite victim because of the geographical variations in snake venoms. The best and most acceptable form of treatment is the use of antivenom; however, it must be administered as soon as possible since it is not so effective at reducing local signs of envenomation such as necrosis. The antivenom in the United States is in short supply, expensive and may not even be the most effective for neutralizing all North American snake venoms. In this study, we tested two antivenoms. The first was a Crotalidae Polyvalent Fab fragment with Ovine origin (FabO) manufactured in London, and the second was Antivipmyn, a Mexican manufactured antivenom that is F(ab')(2) fragment produced in horse (Fab(2)H). The efficacy of the two antivenoms was tested with 15 different snake venoms found in North America. Three different assays were used to test the efficacy of the antivenoms, the in vivo serum protection test (ED(50)), antihemorrhagic and anticoagulant. The Fab(2)H antivenom was most effective in neutralizing the hemorrhagic activity of 78% of the hemorrhagic venoms used in this study. In the ED(50) assay, the Fab(2)H antivenom was effective in neutralizing all venoms used in this study, while FabO neutralized all but C. m. molossus venom. However, in most cases, FabO required less antivenom than Fab(2)H antivenom to neutralize three LD(50).
authors.affiliation: Department of Biology, Natural Toxins Research Center (NTRC), Texas A&M University-Kingsville, MSC 158, Kingsville, TX 78363-8202, USA.
authors.forename: Elda E
authors.initials: EE
authors.lastname: Sánchez
authors.forename: Jacob A
authors.initials: JA
authors.lastname: Galán
authors.forename: John C
authors.initials: JC
authors.lastname: Perez
authors.forename: Alexis
authors.initials: A
authors.lastname: Rodríguez-Acosta
authors.forename: Peter B
authors.initials: PB
authors.lastname: Chase
authors.forename: John C
authors.initials: JC
authors.lastname: Pérez
mesh_terms: D000818:Animals; D000997:Antivenins / Q000276:immunology / Q000627:therapeutic use*; D001681:Biological Assay; D001777:Blood Coagulation / Q000187:drug effects; D003435:Crotalid Venoms / Q000037:antagonists & inhibitors / Q000276:immunology / Q000633:toxicity*; D005340:Fibrinogen / Q000276:immunology / Q000378:metabolism; D006470:Hemorrhage / Q000139:chemically induced / Q000517:prevention & control*; D006736:Horses; D007140:Immunoglobulin Fab Fragments / Q000627:therapeutic use*; D007928:Lethal Dose 50; D009500:Neutralization Tests; D009656:North America; D011817:Rabbits; D012756:Sheep; D013045:Species Specificity; D013927:Thrombosis / Q000139:chemically induced / Q000517:prevention & control*
chemical_list: D000997:Antivenins; D003435:Crotalid Venoms; D007140:Immunoglobulin Fab Fragments; D005340:Fibrinogen