Venom with an altitude: Coagulopathy following an envenomation by the high-mountain snake Gloydius monticola (Likiang Pitviper) in Yunnan Province, China

The Likiang pitviper ( Gloydius monticola ) is a high-altitude species endemic to northwestern Yunnan Province, China, and its venom effects on humans have not previously been documented. We report the first confirmed case of human envenomation by G. monticola , resulting in severe and progressive coagulopathy. A 34-year-old male was bitten on the hand while photographing an adult specimen at approximately 3500 m elevation. Initial local pain and swelling were followed by delayed but catastrophic coagulopathy, characterized by profound hypofibrinogenemia, markedly prolonged clotting times, elevated fibrin degradation products, and secondary haemorrhagic manifestations. Early administration of Gloydius brevicaudus monovalent antivenom did not prevent progression of coagulopathy. In contrast, subsequent treatment with Deinagkistrodon acutus monovalent antivenom was possibly associated with gradual and sustained recovery of coagulation parameters. This case demonstrates that G. monticola venom can induce life-threatening coagulopathy and should be regarded as medically significant. The possible differential clinical response to antivenoms highlights the limitations of phylogenetic relatedness as a predictor of antivenom efficacy and underscores the need for venom characterization and systematic evaluation of antivenom cross-neutralization for understudied pitviper species. • First confirmed human bite by Gloydius monticola (Likiang Pitviper) • Delayed onset, catastrophic coagulopathy with profound hypofibrinogenemia • Gloydius brevicaudus antivenom did not arrest coagulopathy progression • Deinagkistrodon acutus antivenom suggestive of recovery