Proteomic analysis reveals geographic variation in venom composition of Russell's Viper in the Indian subcontinent: implications for clinical manifestations post-envenomation and antivenom treatment.

INTRODUCTION: The Russell's Viper (RV) (Daboia russelii), a category I medically important snake, is responsible for a significant level of morbidity and mortality in the Indian sub-continent. Areas covered: The current review highlights the variation in RV venom (RVV) composition from different geographical locales on the Indian sub-continent, as revealed by biochemical and proteomic analyses. A comparison of these RVV proteomes revealed significant differences in the number of toxin isoforms and relative toxin abundances, highlighting the impact of geographic location on RVV composition. Antivenom efficacy studies have shown differential neutralization of toxicity and enzymatic activity of different RVV samples from the Indian sub-continent by commercial polyvalent antivenom (PAV). The proteome analysis has provided deeper insights into the variation of RVV composition leading to differences in antivenom efficacy and severity of clinical manifestations post RV-envenomation across the Indian sub-continent. Expert commentary: Variation in RVV antigenicity due to geographical differences and poor recognition of low molecular mass (<20 kDa) RVV toxins by PAV are serious concerns for effective antivenom treatment against RV envenomation. Improvements in immunization protocols that take into account the poorly immunogenic components and geographic variation in RVV composition, can lead to better hospital management of RV bite patients.