The use of the chick biventer cervicis preparation to assess the protective activity of six international reference antivenoms on the neuromuscular effects of snake venoms in vitro.

The protective activity of some antivenoms on the neuromuscular activity in vitro of six snake venoms was established in order to test the feasibility of using a simple isolated nerve-muscle preparation to compare different antivenoms. Six venoms designated as International Reference Venoms by the World Health Organization (WHO) were used: Echis carinatus (Iran), Echis carinatus (Mali), Naja naja kaouthia, Notechis scutatus, Trimeresurus flavoviridis, and Vipera russelli (Thailand). The chick biventer cervicis nerve-muscle preparation was used to detect neurotoxic and myotoxic effects. The ratio of the amount of antivenom needed to neutralize a dose of venom (w/w) was calculated in order to quantify the potencies of the antivenoms. The antivenom to venom ratios were 1000 for Echis carinatus (Mali) and for Notechis scutatus; 100 for Naja naja kaouthia and Vipera russelli; and 10 for Echis carinatus (Iran) and Trimeresurus falvoviridis. It is concluded that in vitro assays using the chick biventer cervicis preparation could be used to compare the relative potencies of different antivenoms at neutralizing myotoxic and neurotoxic toxins in snake venoms.