Ovophis tonkinensis envenoming presenting with severe isolated thrombocytopenia and local necrosis: A case report

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  Image Credit: iNaturalist (c) randall_f –  some rights reserved (CC BY-NC) Ovophis tonkinensis envenoming presenting with severe isolated thrombocytopenia and local necrosis: A case report Abstract Pit viper envenoming commonly causes venom-induced consumption coagulopathy with hypofibrinogenaemia. However, isolated thrombocytopenia without fibrinogen depletion is less recognised and may alter transfusion strategy. We report a confirmed  Ovophis tonkinensis  bite from northern Vietnam presenting with severe isolated thrombocytopenia and local necrosis. The case highlights the importance of serial platelet monitoring, awareness of fibrinogen availability and appropriate timing of antivenom and platelet support in resource-limited tropical settings. Duc ND, Hong Anh LN, Hong Khanh LN, Bach ND. Ovophis tonkinensis envenoming presenting with severe isolated thrombocytopenia and local necrosis: A case report. Tropical Doctor . 2026;0(0). doi: 10.1177/00494755261435153

Functional and immunological variability of Viperid venoms across continents and cross-neutralization by Peruvian antivenoms

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By Holger Krisp - Own work, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=75251850

Functional and immunological variability of Viperid venoms across continents and cross-neutralization by Peruvian antivenoms

Abstract

Snake envenomation remains a significant neglected tropical disease primarily treated with antivenoms, which, despite inherent limitations, continue to be the gold standard therapy. Snake venoms exhibit extensive compositional and functional diversity, posing challenges for universal antivenom efficacy. This study comprehensively evaluated venom composition, enzymatic activities, and immunological cross-reactivity across 24 Viperidae species from diverse geographic regions. Using protein profiling, enzymatic assays (proteolytic, amidolytic, clotting, and PLA2 activities), and phylogenetic analyses, we revealed marked interspecific variation. Bothrops species exhibited elevated SVMP-driven proteolytic activity, while Crotalus venoms demonstrated more balanced enzymatic profiles. Phylogenetic clustering highlighted evolutionary divergence and functional convergence among taxa. Immunoreactivity assays with Peruvian antibothropic, anticrotalic, and antilachesic antivenoms showed broad cross-recognition within Bothrops and Crotalus venoms, but limited efficacy against more distantly related Viperinae species. Western blot analyses confirmed these specificity patterns. Neutralization assays revealed differential inhibition: antibothropic antivenom effectively neutralized proteolytic activity, whereas anticrotalic antivenom preferentially inhibited PLA2-mediated effects. This functional variability highlights the biochemical complexity of viperid venoms and the constraints of current antivenoms. Our findings emphasize the urgent need to develop improved, broadly effective antivenom formulations capable of targeting the diverse toxin profiles of geographically and phylogenetically distinct viperid species, ultimately enhancing clinical management of snakebite envenomation worldwide.


Torrejón, D., Llontop, A., Proléon, A., Lazo, F., Urra, F., Yarlequé, A., & Vivas-Ruiz, D. E. (2026). Functional and immunological variability of Viperid venoms across continents and cross-neutralization by Peruvian antivenoms. Biochimie, 240, 88-99. https://doi.org/10.1016/j.biochi.2025.10.013