Green pitvipers are responsible for the majority of bites in tropical and sub-tropical Asia. Most are considered low priority species and most bites can be treated without the use of antivenom; however, a few bites produce more serious symptoms. Ongoing taxonomic confusion and uncertainty about distribution of
species makes these cases difficult to explain. Here, we report on new data from north and northeast India, where the green pitvipers present are more related to SE Asian taxa (Trimeresurus sensu stricto, Viridovipera, Popeia, Himalayophis) than to those in the rest of Peninsular India (Craspedocephalus). We characterised the proteomic content of the venom of representatives of Viridovipera, Popeia and Trimeresurus and performed in-vitro biochemical assays to understand venom composition and their pathophysiological roles. These venoms display diverse PLA2 activity, coagulation activity, thrombin-like activity, haemolytic activity and
proteolytic activity which correlate with clinical manifestations, with both local symptoms, such as extensive swelling and pain, as well as systemic abnormalities such as long-lasting (5-10 days) coagulopathy. Immuno-reactivity studies with Indian Polyvalent antivenoms showed inefficient neutralizations of venom toxins of the studied venoms, especially of lower molecular weight proteins, while Thai Green Pitviper antivenom was ineffective against venom of Popeia and Viridovipera spp. venom but showed good neutralization of Trimeresurus species venom. As the Thai green pitviper antivenom is raised against the venom of a related
species, Trimeresurus albolabris, this underlines the utility of taking the recent taxonomic revision of Trimeresurus sensu lato into account.