Quantitative Characterization of the Hemorrhagic, Necrotic, Coagulation-Altering Properties and Edema-Forming Effects of Zebra Snake () Venom.

This study was designed to investigate the cytotoxicity and haemotoxicity of the Western barred (zebra) spitting cobra () 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 . The rabbit skin minimum hemorrhagic dose (MHD) for was 9.8g. The minimum necrotizing dose (MND) for venom was 12.2g. The venom showed linear dose-dependent procoagulant activity on goat blood (p<0.05). Likewise, venom showed linear dose-dependent thrombolytic activity on goat blood (p<0.05, n = 6). Subplantar injection of venom (25g, 50g, 75g, and 100g) 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% (25g venom) to 17.6% (100g venom). In conclusion, though belongs to the genus , 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 venom toxins as a prelude to the development of an antivenom.