A preclinical assessment was performed on the neutralizing efficacy of a whole
IgG polyspecific
antivenom (EchiTAb-Plus-ICP), designed for the treatment of
snakebite envenomings in Nigeria. It was generated by immunizing horses with the
venoms of Echis ocellatus, Bitis arietans and Naja nigricollis, the most medically important species in Nigeria.
Antivenom was tested against the
venoms of E. ocellatus, Echis leucogaster, Echis pyramidum leakeyi, B. arietans, Bitis gabonica, Bitis rhinoceros and Bitis nasicornis. The neutralization of the
venom toxins responsible for the lethal, hemorrhagic,
coagulant and local necrotizing activities was assessed, since these are the most significant effects that characterize envenoming by these species. Echis sp
venoms exerted lethal, hemorrhagic,
coagulant and necrotizing effects, whereas the Bitis sp
venoms tested induced lethality,
hemorrhage and
necrosis, but were devoid of
coagulant activity. The
antivenom was effective in the neutralization of all effects tested in all
venoms. Highest neutralization was achieved against the
venoms of E. ocellatus and B. arietans, and the lowest neutralizing potency was against the
venom of B. nasicornis, a species that has a low clinical relevance. It is concluded that EchiTAb-Plus-ICP, whilst specifically designed for Nigeria, has a good preclinical neutralizing profile against homologous and heterologous viperid
venoms from other sub-Saharan African locations. It therefore constitutes a promising therapeutic option for the treatment of
snakebite envenoming in this region.