Local climate can be used to predict the venom characteristics of Russell’s viper, a deadly snake that is widespread in India, helping clinicians to provide targeted therapies for snake bite victims, according to a study published by IISc researchers on April 10 in the journal PLOS Neglected Tropical Diseases.
Russell’s viper (Daboia russelii) is found across the Indian subcontinent and is responsible for over 40% of snake bite-related deaths in India each year. Its venom is extremely variable, and snake bites cause different symptoms in different regions of India. The toxic effects of snake venom are caused by the concentrations of different enzymes, which can be influenced by many factors, including prey availability and climate. However, the factors driving variation in Russell’s viper venom are unknown.
To investigate, researchers analysed venom samples from 115 snakes collected in 34 locations across India. They tested the activity of venom toxins, including enzymes that break down proteins, phospholipids and amino acids. Next, they used historical climate data to understand the relationship between venom composition and the local climate where the snakes were caught. They found that temperature and rainfall partly explained regional variation in snake venom composition.
Protease activity showed the closest relationship to climate variables, whereas the activity of animo acid oxidases was unaffected by climate. Snakes in drier regions of India tended to have higher protease activity. The researchers used this data to create a map of expected venom types across Russell’s viper’s range in India, which could be used to predict the clinical symptoms of snake bites in different regions.
The venom maps developed in this study “can guide the deployment of targeted therapies and treatment protocols across the biogeographically diverse Indian subcontinent and improve clinical treatment outcomes of D. russelii envenoming”, the authors write.
“Recent studies from our lab have shed light on the influence of biotic factors, such as developmental shifts in diet, on Russell’s viper venom composition and toxicity. However, the effects of abiotic or environmental factors remained unstudied. Here, we highlight, for the first time, the role of climatic conditions, such as temperature, humidity and rainfall, in driving the biochemical functions of Russell’s viper venoms,” Dr. Kartik Sunagar from the Centre for Ecological Sciences, IISc and the corresponding authors says in a release.
Published – April 12, 2025 09:00 pm IST