Abstract
This study was designed to investigate the cytotoxicity and haemotoxicity of the Western barred (zebra) spitting cobra (Naja nigricincta nigricincta) venom to help explain atypical and inconsistent reports on syndromes by Namibian physicians treating victims of human ophidian accidents. Freeze-dried venom milked from adult zebra snakes was dissolved in phosphate buffered saline (PBS) for use in this study. Haemorrhagic and necrotic activity of venom were studied in New Zealand albino rabbits. Oedema-forming activity was investigated in 10-day-old Cobb500 broiler chicks. Procoagulant and thrombolytic activity was investigated in adult Kalahari red goat blood in vitro. The rabbit skin minimum hemorrhagic dose (MHD) for N. n. nigricincta was 9.8μg. The minimum necrotizing dose (MND) for N. n. nigricincta venom was 12.2μg. The N. n. nigricincta venom showed linear dose-dependent procoagulant activity on goat blood (p<0.05). Likewise, N. n. nigricincta venom showed linear dose-dependent thrombolytic activity on goat blood (p<0.05, n = 6). Subplantar injection of N. n. nigricincta venom (25μg, 50μg, 75μg, and 100μg) into chick paw resulted in peak oedema of 35.5%, 38.5%, 42.9%, and 47.5%, respectively, two hours after injection. Paw oedema subsided within five hours to a mean volume ranging from 5% (25μg venom) to 17.6% (100μg venom). In conclusion, though N. n. nigricincta belongs to the genus Elapidae, the current study has shown its venom to possess potent hemorrhagic, necrotic (cytotoxic), and paradoxically, both procoagulant and thrombolytic activity. The authors propose further work to fractionate, isolate, and elucidate the structure of the various N. n. nigricincta venom toxins as a prelude to the development of an antivenom.
Highlights
Since time immemorial, man has always suffered from envenomation resulting from snakebites
The minimum hemorrhagic dose (MHD) determined from this relationship for N. n. nigricincta was 9.8μg
The minimum necrotizing dose (MND) was determined from this relationship for N. n. nigricincta (12.4 μg)
Summary
Man has always suffered from envenomation resulting from snakebites. In Namibia, like in most other developing countries, the majority of snake bites result from the overlap of human and snake habitats, domiciliation of rodents (main prey of most snakes), the nocturnal and heat seeking poikilothermic nature of snakes, and accidents during snake handling. Some of these snakebites lead to fatalities and wound complications culminating in debilitating physical deformities in victims [4, 5] and associated socioeconomic problems resulting from these disabilities [6, 7]. The vast size of Namibia as a country poses a potential problem of bringing emergency health care to such snakebite victims
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
