An objective approach to antivenom therapy and assessment of first aid measures snake bite in

Treatment of systemic envenoming in snake-bite victims has, in the past, depended almost entirely on the individual clinician’s experience in assessing the severity of envenoming. The ef® cacy of treatment is obviously related to the neutralizing potency of the antivenom used, the route by which it is administered and the dose. The development of enzyme immunoassays has permitted a more scienti® c appraisal, allowing estimation of circulating speci® c venom and antivenom concentrations at any time after the bite in the patient’ s blood. It is therefore possible to measure accurately the ef® cacy of antivenom in the neutralization and clearance of venom antigen. In Brazil, it appears that clinicians treat patients with excessive amounts of highly ef® cient antivenoms and this results in an unacceptably high incidence of reactions. In Sri Lanka, the use of imported, Indian antivenom is relatively ineffective in neutralizing the venoms of Sri Lankan snakes, demonstrating the real problem of venom variability within individual species. In West Africa, the improved clearance of venom following treatment of Echis victims with a monospeci® c as opposed to a polyspeci® c antivenom has been demonstrated, and new, smaller fragment, Fab antivenoms have been developed and are now under clinical assessment. Such clinically-based immunological studies should result in more ef® cient and controlled use of expensive antivenoms for treatment of systemic envenoming and the accurate assessment of newly designed products. Such studies also emphasise the importance of individual countries producing their own antivenoms for treatment of systemic envenoming. Likewise, the use of such objective systems now enables the use of ® rst-aid measures such as tourniquets to be properly assessed.