Information upon each antivenom described by the product insert.

<p>Information upon each antivenom described by the product insert.</p

The concentration of protein (F(ab’)₂-fragment of IgG) in each vial of antivenom.

<p>The concentration of protein (F(ab’)₂-fragment of IgG) in each vial of antivenom.</p

The IgG specificities of six commercial antivenoms to venom proteins of six sub-Saharan Africa venoms.

<p>Venoms (10 μg) of <i>B</i>. <i>arietans</i>, <i>E</i>. <i>p</i>. <i>leakeyi</i>, <i>N</i>. <i>nigricollis</i>, <i>N</i>. <i>pallida</i>, <i>N</i>. <i>haje</i> and <i>D</i>. <i>polylepis</i> were separated by reduced SDS-PAGE and visualised by coomassie blue staining (Panel A). Venom proteins in identical gels were transferred to nitrocellulose blots and incubated with 1:5,000 dilutions of naïve Horse IgG (B), the ‘gold standard’ SAIMR polyvalent (C) and SAIMR ECHIS CARINATUS (D) antivenoms, and the ‘test’ Sanofi Pasteur (E), VINS (F), INOSAN (G) and Premium Serums & Vaccines (H) antivenoms. The antivenoms were not standardised to 5 mg/ml as in the ELISA assays.</p

The IgG reactivity (titre) of six commercial antivenoms against six sub-Saharan Africa venoms determined by titration ELISA.

<p>All antivenoms were adjusted to 5 mg/ml in PBS prior to being diluted 1 in 100 and then serially diluted 1 in 5 and applied to venoms. Panel (A) = SAIMR polyvalent, (B) = SAIMR ECHIS CARINATUS, (C) = Sanofi Pasteur, (D) = VINS (E) = INOSAN, (F) = Premium Serums & Vaccines (PS&V) antivenoms. Venoms: <i>B</i>. <i>arietans</i> (blue), <i>E</i>. <i>p</i>. <i>leakeyi</i> (red), <i>N</i>. <i>nigricollis</i> (green), <i>N</i>. <i>pallida</i> (purple), <i>N</i>. <i>haje</i> (orange) and <i>D</i>. <i>polylepis</i> (black). Results are the mean of three replicates with error bars representing standard deviation (SD). Error bars are not shown where SD is smaller than data point. The reactivity of control, naïve horse IgG to each venom was consistently low at each dilution for each venom (mean OD 405 nm = 0.07 ± 0.005). For interested readers, the same data as in Fig 3 is presented in Supplementary <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0005969#pntd.0005969.s001" target="_blank">S1 Fig</a> to facilely compare binding to each of the six venoms.</p

The relative IgG-venom binding avidity of six commercial antivenoms against six sub-Saharan Africa venoms determined by chaotropic ELISA.

<p>1:1,000 dilutions of 5 mg/ml standardized antivenoms were allowed to bind to venom coated plates before being exposed to NH₄SCN at increasing concentrations for 15 minutes. Panel (A) = SAIMR polyvalent, (B) = SAIMR ECHIS CARINATUS, (C) = Sanofi Pasteur, (D) = VINS (E) = INOSAN, (F) = Premium Serums & Vaccines (PS&V) antivenoms. Venoms: <i>B</i>. <i>arietans</i> (blue), <i>E</i>.<i>p</i>. <i>leakeyi</i> (red), <i>N</i>. <i>nigricollis</i> (green), <i>N</i>. <i>pallida</i> (purple), <i>N</i>. <i>haje</i> (orange) and <i>D</i>. <i>polylepis</i> (black). Results are the mean of three replicates with error bars representing standard deviation (SD). Error bars are not shown where SD is smaller than data point. The reactivity of control, naïve horse IgG to each venom was consistently low at each dilution for each venom (mean OD 405 nm = 0.05 ± 0.004). For interested readers, the same data as in Fig 4 is presented in Supplementary <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0005969#pntd.0005969.s002" target="_blank">S2 Fig</a> to facilely compare binding to each of the six venoms.</p

Variant efficacy of the ‘test’ antivenoms against the lethal effects of the six East African venoms in a mouse model.

<p>The percent survival of mice injected with lethal doses of venom mixed with the ‘test’ antivenoms in volumes equivalent to half (0.5), the same (1x) or 2.5-fold more (2.5x) of the 100% effective volume of the SAIMR ‘gold standard’ antivenoms was used to identify whether the ‘test’ Premium Serums & Vaccines, VINS, INOSAN and Sanofi Pasteur antivenom were ineffective (red bar), partially effective (yellow bar), effective but requiring a higher dose of antivenom than the SAIMR products (light green bar), an equivalent dose efficacy as the SAIMR products (dark green bar) or a superior dose efficacy than the SAIMR antivenoms (blue bar). The test venoms were East African puff adders (<i>B</i>. <i>arietans</i>; 97.8 μg<i>)</i>, saw-scaled vipers (<i>E</i>. <i>p</i>. <i>leakeyi</i>; 80.5 μg), black necked spitting cobras (<i>N</i>. <i>nigricollis</i>; 61.0 μg), red spitting cobras (<i>N</i>. <i>pallida</i>; 46.5 μg), Egyptian cobras (<i>N</i>. <i>haje</i>; 40.8 μg) and black mambas (<i>D</i>. <i>polylepis</i>; 30.8 μg). Please refer to Supplementary <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0005969#pntd.0005969.s004" target="_blank">S1 Table</a> for details on antivenom volumes, amounts of antivenom in mg, snake geographical origin and venom LD₅₀ dose used for each experimental group. * Mice died from the high density of antivenom/venom complexes that precipitate out of solution, not from venom-induced effects. With experience, the symptoms of this cause of death can be readily distinguished from that caused by venom. This occurs occasionally in murine preclinical testing as a consequence of the 30 minute, 37°C incubation of the venom/antivenom mixture prior to injection. It likely has no clinical relevance, but can obfuscate preclinical results.</p

The murine venom lethal dose (LD₅₀) of the East African snakes.

<p>The venom LD₅₀ is provided as μg venom per mouse and as μg venom per gram body weight as both metrics are used in the literature.</p

Information upon each antivenom described by the product insert.

<p>Information upon each antivenom described by the product insert.</p

Costs to Kenya hospitals of antivenoms (purchased through Mission for essential drugs & supplies (US$1 = Kshs 101.8; Feb 2016).

<p>Costs to Kenya hospitals of antivenoms (purchased through Mission for essential drugs & supplies (US$1 = Kshs 101.8; Feb 2016).</p

Concerns over an antivenom widely marketed in sub-Saharan Africa.

<p>Why are venoms from the Asian Russell’s viper (<i>Daboia russelii</i>—incorrectly labelled here as <i>Vipera russelli</i>) and saw-scaled viper (<i>Echis carinatus</i>) included in its efficacy statement?.</p