Enzyme-linked immunosorbent assay of venom-antibodies in human victims of snake bite.

The development, incidence, persistence, and significance of specific venom-antibodies were studied in 357 human victims of snake bite in Nigeria using the enzyme-linked immunosorbent assay (ELISA). Venom-antibody was not detected within 2 weeks of envenoming but was present within 2 months of the bite despite therapeutic antivenom being given. ELISA confirmed the medical importance of the carpet viper Echis carinatus in Nigeria but also showed that bites by other venomous species are more common than previously suspected. Venom-antibodies may wane with time but nevertheless were still present 40 years after the original envenoming. Clinical studies suggested that venom-antibody titres too low to be detected by ELISA may be boosted with further bites; and more importantly, homologous venom-antibody may afford significant protection against further envenoming. ELISA can help both in advancing the epidemiology of snake bite and in exploring the role of active immunization.