A new study from the Indian Institute of Science (IISc), published on April 10 in PLOS Neglected Tropical Diseases, has found that local climate conditions—especially temperature and rainfall—can help predict the venom characteristics of Russell’s viper, one of the most dangerous snakes in India. 

The deadly snake well-known acoss the country as Kander or Kandari in Hindi, Ghonas & Khadchit in Marathi, Chandrabora in West Bengal and parts of Odisha, Manjara in parts of Maharashtra and Central India, Tiwadi in Gujarat and Rajasthan, Pogonas Karnataka and Andhra Pradesh and Anna Cheeni in Tamil Nadu and Moroli & Bora Saap in Northeast India representing its presence across the country’s multiple agro-climatic conditions.

The research, led by evolutionary biologist Dr. Kartik Sunagar, could improve how doctors treat snakebite victims by offering location-specific insights into venom toxicity.

Russell’s viper (Daboia russelii), widespread across the Indian subcontinent, is responsible for over 40% of snakebite-related deaths in India each year, according to government estimates and data compiled by the Indian Council of Medical Research (ICMR). Its venom is not uniform; it varies across regions and causes a range of symptoms in victims—from bleeding disorders and kidney failure to localised tissue damage. Understanding this variability is crucial because most antivenoms used in India are made using venom from a limited geographical source, often making them less effective in other regions.

The IISc team collected venom samples from 115 vipers across 34 locations throughout India. The samples were then tested for the activity of specific venom enzymes, such as proteases, phospholipases, and amino acid oxidases, which are responsible for breaking down tissues and causing the severe symptoms seen in snakebite cases.

By correlating this biochemical data with historical weather records, researchers found that vipers from drier areas had venom with higher protease activity, making the venom more likely to cause rapid tissue destruction. In contrast, the activity of amino acid oxidase did not show any clear link with climate. The findings indicate that temperature and rainfall partly influence the biochemical make-up of the venom, offering a new lens through which to understand venom variability.

"Russell's viper is arguably the clinically most important snake species in the world. It kills and maims more people than any other snake species," said Dr Sunagar in a statement. "We now show, for the first time, that climatic conditions like humidity and rainfall play a major role in shaping the venom’s biochemical profile."

This discovery allowed the researchers to create the first detailed “venom map” of India, showing expected venom profiles across different regions. Such a tool could help doctors anticipate the kind of symptoms patients are likely to develop after a bite in a particular area. It could also guide the development of region-specific antivenoms or treatments targeting specific venom components.

Currently, India produces polyvalent antivenoms based on venom from snakes found in Tamil Nadu, but their efficacy drops significantly when used against snakes from other regions. A study published in Scientific Reports (2020) also emphasised the poor neutralising capacity of existing antivenoms against northern and eastern populations of Russell’s vipers.

Experts believe this new climate-based venom profiling could bridge that treatment gap. “Targeted therapies, such as recombinant toxin-specific antibodies, will only succeed if we first understand the diversity in venom composition,” noted Dr Sunagar.

Snakebite is a neglected public health crisis in India, killing an estimated 50,000 people annually, mostly in rural areas. This study is a reminder that solutions must be as diverse as the landscapes where these snakes live. Climate-informed venom profiling is not just a scientific advancement—it’s a life-saving tool in a country where snakebite deaths outnumber fatalities from many infectious diseases. As climate change alters local weather patterns, such research becomes even more critical.