Brown snakes (Pseudonaja genus): venom yields, prothrombin activator neutralization and implications affecting...

Area of Science:

• Herpetology
• Toxicology
• Biochemistry

Background:

• Fatal brown snake (Pseudonaja genus) bites are a growing concern.
• Previous studies have not fully characterized venom yields or antivenom efficacy against specific venom components.

Purpose of the Study:

• To quantify venom yields from various brown snake species.
• To assess the binding avidity of Brown snake antivenom (BS-AV) to venom components, particularly prothrombin activators (PAs).
• To investigate the toxicological effects of PAs and the efficacy of BS-AV in neutralizing them.

Main Methods:

• Collected venom from 66 brown snake milkings over 15 months.
• Analyzed venom composition using SDS-PAGE and Western blotting.
• Determined the LD50 of P. inframacula venom.
• Assessed BS-AV avidity and neutralization kinetics against P. textilis prothrombin activator (Pt-PA).
• Administered Pt-PA to rats to observe toxicological effects.

Main Results:

• Venom yields were higher than previously reported across all species.
• BS-AV showed significantly lower avidity for the 190 kD PA component compared to neurotoxins.
• Pseudonaja venoms contained higher proportions of PA compared to Taipan or Fierce snake venoms.
• Pt-PA neutralization by BS-AV was time-dependent, with 40% remaining unneutralized after 30 minutes.
• Pt-PA administration caused acute disseminated intravascular coagulation in rats.

Conclusions:

• Brown snake venoms are rich in prothrombin activators, which are poorly targeted by current BS-AV.
• The prothrombin activator component is responsible for disseminated intravascular coagulation.
• Improvements to BS-AV are necessary to enhance its effectiveness against brown snake envenomation.