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

Integrative taxonomy for widow spiders (Araneae: Theridiidae) surveillance in Mexico City, Mexico

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Integrative taxonomy for widow spiders (Araneae: Theridiidae) surveillance in Mexico City, Mexico

Abstract

The spiders of the genus Latrodectus (Theridiidae), commonly known as widow spiders, includes species of medical importance due to the high toxicity of their venom. Envenomation can range from mild to severe, occasionally resulting in fatal outcomes. In Mexico, four Latrodectus species have been recorded: L. mactans Fabricius, L. geometricus C. L. Koch, L. hesperus Chamberlin and Ivie, and L. occidentalis Valdez and Espinosa. Until recently, only L. mactans had been reported in Mexico City, though its range appears limited to the Tamaulipecan province and Sierra Madre Oriental. This study reports, for the first time, the presence of L. hesperus and a novel lineage designated as Latrodectus sp. 2 in Mexico City. Spider specimens were collected from 14 localities across Mexico City and identified using both morphological keys and molecular methods. Mitochondrial cytochrome c oxidase subunit I (CO1) was amplified via conventional PCR (Polymerase Chain Reaction) and sequenced to confirm species identity. Of the 24 spiders analyzed, 10 were identified as L. hesperus and 14 as Latrodectus sp. 2. Phylogenetic analyses validated the presence of both taxa.

Salceda-Sánchez, B. ., Sánchez-Montes, S. ., Ibarra-Anaya, A. L. ., Zazueta-Islas, H. M. ., Landa-Flores, M. G. ., Orantes-Ramírez, V. J. ., Mejía-Guevara, M. D. . ., Alarid-Villa, B. G. ., & Huerta, H. . (2025). Integrative taxonomy for widow spiders (Araneae: Theridiidae) surveillance in Mexico City, Mexico. Revista Chilena De Entomología, 51(4). Retrieved from https://www.biotaxa.org/rce/article/view/88152