The Clinical Phenotype of Green Pit Viper (Trimeresurus spp.) Envenomation: A Comprehensive Review

Green pit vipers of the genus Trimeresurus are among the leading causes of snakebite envenomation across tropical and subtropical Asia, yet their clinical phenotype has been less systematically characterized than that of other medically important Asian viperids. This comprehensive review synthesizes the published clinical literature on human Trimeresurus envenomation, drawing on 70 clinical reports encompassing 4720 reported patient episodes, and integrates these data with current taxonomic and venomic evidence. Envenomations cluster in East, Southeast, and South Asia. The single most important limitation of this literature is the unreliability of species attribution: 55% of reported cases are attributed only at genus level or derive from cohorts in which two or more Trimeresurus species are reported together and cannot be separated, a figure consistent with the 56% of snakebites left unidentified in a recent 40,817-patient Chinese survey. Bites involve the extremities almost exclusively, with a predominance of the lower limb (55% versus 45%). The clinical picture is dominated by local effects (i.e., extensive edema and pain in the large majority of patients, secondary infection in approximately one in six, and cutaneous necrosis in approximately one in thirty) and by systemic hemotoxicity driven by venom-induced consumptive coagulopathy. Renal involvement is uncommon, in contrast to Daboia russelii envenomation, and severe neurotoxicity is exceptional. Documented mortality in the reviewed hospital-based literature is low (two deaths among 3387 patients in reports documenting outcome, <0.1%) but is not zero, and hospital-based series cannot capture pre-hospital deaths. Management centers on conservative wound care, serial coagulation monitoring, and selective antivenom administration; routine fasciotomy is not justified without objective evidence of compartment syndrome. Reliable species identification, standardized clinical reporting, and long-term functional follow-up remain the principal unmet needs.