First documented cases of envenomations in mainland China by Ovophis species (mountain pitvipers): Severe coagulopathy and variable antivenom response in two patients from Yunnan Province

Envenomations by Ovophis spp. (mountain pitvipers) are clinically significant yet underreported, especially in mainland China where no confirmed cases have been documented. Here we report two cases of Ovophis envenoming from Yunnan Province that resulted in severe coagulopathy marked by hypofibrinogenemia and elevated D-dimer and FDP levels. In Case 1, a 51-year-old woman bitten by a confirmed O. makazayazaya developed moderate hypofibrinogenemia, which resolved following combined treatment with Deinagkistrodon acutus and Gloydius brevicaudus monovalent antivenoms. In Case 2, a 37-year-old woman bitten by an unidentifiable Ovophis species experienced complete depletion of fibrinogen and prolonged coagulopathy despite treatment with four vials of G. brevicaudus antivenom. These cases highlight the potent coagulotoxic effects of Ovophis venom. Clinical differences between two cases suggest that venom variation and differential antivenom efficacy may influence outcomes. Our findings underscore the need for further research into Ovophis venom composition, cross-neutralization by available antivenoms, and improved species-level identification in clinical settings.