Malumfashi Endemic Diseases Research Project, XIII

AbstractThe spitting cobra, Naja nigricollis, is responsible for most cases of snake bite in the Malumfashi area. A survey revealed an incidence of N. nigricollis bite of 15 to 20 per 100 000 population per year in this part of northern Nigeria, with an estimated natural mortality of 5%. Of 106 victims of previous spitting cobra bite, only 8·5% were treated in hospital, and physical deformity as a result of necrosis from poisoning was present in 19%. This emphasized the fact that statistics based on hospital admissions seriously underestimate snake bite incidence, morbidity and mortality. Naja nigricollis is also important because of its ability to spit venom into the eyes of an assailant. Snake venom ophthalmia is usually regarded as having a benign course, but victims were described who had suffered more serious effects, including blindness. The epidemiology of human encounters with the spitting cobra is discussed, and it is shown that N. nigricollis is able to maintain a close association with man. The cobra is briefly compared with the carpet viper, Echis carinatus, which is more important in less densely populated and cultivated regions of Nigeria. The efficacy of antivenoms in N. nigricollis bite urgently requires clinical investigation.