Pit viper venom toxins (Crotalinae venom toxins) (PVVT)

Pit viper venom toxins are a complex mixture of proteins and peptides found in the venom of snakes from the Crotalinae subfamily, including rattlesnakes, copperheads, and lanceheads (Warrell, 2010). These toxins primarily function to immobilize and digest prey but cause significant pathology in humans, including local tissue necrosis, systemic hemorrhage, and coagulopathy (WHO, 2016). The major molecular components include snake venom metalloproteinases (SVMPs), which degrade the extracellular matrix and basement membranes of blood vessels, and snake venom serine proteases (SVSPs), which interfere with the coagulation cascade (Gutiérrez et al., 2016). Phospholipase A2 (PLA2) enzymes are also prevalent, contributing to myotoxicity, inflammation, and in some species, potent presynaptic neurotoxicity (Slagowski et al., 2022). In clinical medicine, these toxins are the targets of antivenom therapies like CroFab and Anavip, which utilize purified antibody fragments to bind and neutralize the venom components (FDA Anavip Label, 2018). The interaction between the antivenom and the toxins prevents the toxins from reaching their physiological targets, such as fibrinogen or neuromuscular junctions (FDA CroFab Label, 2001). Effective management of envenomation requires monitoring for venom-induced consumptive coagulopathy and thrombocytopenia, which are hallmarks of pit viper envenomation (Warrell, 2010).

Other names

Crotalinae venomRattlesnake venomCrotalid venomPit viper venomNorth American pit viper venomSouth American pit viper venomCentral American pit viper venom

Antivenoms function through passive immunization where venom-specific antibody fragments (Fab or F(ab')2) bind to the antigenic sites of the toxins, neutralizing their enzymatic activity or preventing them from binding to their physiological receptors and substrates (Slagowski et al., 2022; FDA CroFab Label, 2001).