Distribution of four <i>Echis</i> species in Africa and the Middle East.

<p>Key: <i>E. ocellatus</i> – blue, <i>E. pyramidum</i> – red, <i>E. coloratus</i> – green, <i>E. carinatus</i> – purple. Distributions mapped according to the WHO venomous snake distribution database and a recent study of the genus <i>Echis </i><a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0000851#pntd.0000851-Pook1" target="_blank">[16]</a>, <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0000851#pntd.0000851-WHO2" target="_blank">[35]</a>.</p

Extensive cross-specific immunological reactivity between <i>Echis</i> venoms and <i>Echis</i> species-specific IgG antisera revealed by End Point Titration ELISA.

<p>Venom from <i>E. ocellatus</i> (blue bars), <i>E. p. leakeyi</i> (red bars), <i>E. coloratus</i> (green bars) and <i>E. c. sochureki</i> (purple bars) were incubated with serial dilutions (horizontal axis) of IgG antisera raised against <i>E. ocellatus</i> (A), <i>E. p. leakeyi</i> (B), <i>E. coloratus</i> (C) and <i>E. c. sochureki</i> (D) and the optical density determined (vertical axis).</p

Venom affinity-chromatography to measure the binding strength of each <i>Echis</i> species-specific antisera to each venom.

<p>The amount of IgG from each <i>Echis</i> species specific antisera that remained bound to the <i>Echis</i> venom affinity chromatography column is displayed as a percent of the 3 mg of each IgG added to the column. Italicised values highlight homologous venom-antivenom results.</p

The End Point Titre of each <i>Echis</i> species-specific IgG antisera to each <i>Echis</i> venom.

<p>Italicised values highlight homologous combinations of venom-IgG antisera.</p

<i>Echis</i> species-specific IgG antisera exhibit extensive cross-specific venom protein reactivity.

<p>The venom proteins of <i>E. ocellatus (E.o)</i>, <i>E. p. leakeyi (E.p.l)</i>, <i>E. coloratus (E.c)</i> and <i>E. c. sochureki (E.c.s)</i> visualised using reduced SDS-PAGE (A), after immunoblotting, showed extensive cross-specific reactivity with IgG antisera specific to <i>E. ocellatus</i> (B), <i>E. p. leakeyi</i> (C), <i>E. coloratus</i> (D) <i>E. c. sochureki</i> (E). The sera were diluted 1∶5,000 and 7µg of each venom was used in all gels.</p