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Snake venoms have evolved in several families of Caenophidae, and their toxins have been assumed to be biochemical weapons with a role as a trophic adaptation. However, it remains unclear how venom contributes to the success of venomous species for adaptation to different environments. Here we compared the venoms from Bothrocophias hyoprora , Bothrops taeniatus , Bothrops bilineatus smaragdinus , Bothrops brazili , and Bothrops atrox collected in the Amazon Rainforest, aiming to understand the ecological and toxinological consequences of venom composition. Transcriptomic and proteomic analyses indicated that the venoms presented the same toxin groups characteristic from bothropoids, but with distinct isoforms with variable qualitative and quantitative abundances, contributing to distinct enzymatic and toxic effects. Despite the particularities of each venom, commercial Bothrops antivenom recognized the venom components and neutralized the lethality of all species. No clear features could be observed between venoms from arboreal and terrestrial habitats, nor in the dispersion of the species throughout the Amazon habitats, supporting the notion that venom composition may not shape the ecological or toxinological characteristics of these snake species and that other factors influence their foraging or dispersal in different ecological niches.

In the Brazilian Amazon, envenomations by lancehead pit vipers prevail across the region, while bushmaster (Lachesis muta) envenomations are rarely confirmed. Here, we described a moderate snakebite, diagnosed as a lancehead pit viper envenomation upon admission and treated with four vials of Bothrops antivenom. Blood remained unclottable for 4 days of hospitalization. On day 4, after admission, the patient presented pictures of the perpetrating snake to the hospital staff, which was identified as a Lachesis muta specimen. After administering 10 vials of Lachesis antivenom, blood became clottable 12 hours after treatment. The patient was discharged without complaints.

Introduction: Snake venom composition shows significant inter- and intra-species variation. In the case of the viperid species Bothrops atrox , responsible for the majority of snakebites in the Amazon region, geographical and ontogenetic variables affect venom composition, with ecological and medical implications. Previous studies had shown that venom from neonate and juvenile Bothrops specimens have a higher in vitro coagulant activity. The aim of this investigation was to assess the association of clinical outcomes, such as venom-induced coagulopathy and local complications, with B. atrox ontogenetic variables. Methods: This study explored the relationship between some clinical parameters in patients suffering envenomations by B. atrox in the Amazon and several morphometric parameters of the snake specimens causing the bites. Results: There were 248 specimens confirmed as agents of envenomation, mostly female snakes (70.5%) and classified as juveniles (62.7%). Patients bitten by neonates compared to adult snakes [OR = 2.70 (95%CI 1.15-6.37); p  = .021] and by snakes with white tail tip [OR = 1.98 (95%CI 1.15-3.41); p  = .013] were more likely to develop coagulopathy. Time from patient admission to the unclottable blood reversion was not affected by the snake gender ( p  = .214) or age ( p  = .254). Patients bitten by neonate ( p  = .024) or juvenile snakes ( p  < .0001) presented a lower frequency of moderate to severe edema, as compared to those bitten by adult snakes. In agreement with experimental observations, patients bitten by neonates and by snakes with a white tail tip were more likely to develop coagulopathy than those bitten by adult snakes. In contrast, envenomations by adult snakes were associated with a higher incidence of severe local edema. Conclusion: Despite these variations, no difference was observed in the time needed to recover blood clotting in these patients after Bothrops antivenom administration.