Russell's Viper

Like the saw-scaled viper, its danger is a matter of how and where it lives rather than of having the single most toxic venom. Russell's viper is common across a densely populated region, and it thrives on farmland, following rats into rice paddies, field margins, and grain stores, exactly where large numbers of people work by hand. It is easily disturbed, hisses and strikes hard, and its venom does severe, complex damage that is difficult to treat, particularly the kidney injury. Many bites happen far from a hospital, antivenom supply and quality vary, and traditional first aid is often ineffective, so a bite that would be survivable with fast, correct treatment too often is not.

The venom is a mixture that acts on several systems. It interferes with blood clotting, at first triggering clotting and then using up the clotting factors so that blood will not clot at all, which leads to persistent bleeding from the bite, the gums, and internal organs. It commonly injures the kidneys, sometimes severely enough to require long-term dialysis or a transplant. It can raise capillary leakiness, dropping blood pressure, and in some regions it causes drooping eyelids, weakness, and breathing difficulty. And in a minority of survivors it damages the pituitary gland, producing hormone problems that emerge much later. Prompt hospital treatment with the correct antivenom, plus support for clotting, kidneys, and blood pressure, is what saves lives.

The standard measures are simple and effective. Wearing shoes or boots, rather than going barefoot or in sandals, prevents many bites, since most are to the foot or lower leg. Using a light when walking after dark lets people see and avoid a coiled snake, and Russell's vipers are often active in the cooler hours. Keeping rodents down by storing grain properly and clearing rubbish removes the snake's food and its reason to be near houses. Sleeping on a raised bed and clearing vegetation from around dwellings also help, as does going straight to a hospital rather than a traditional healer if a bite occurs.

They are close relatives but now treated as separate species. The snake of India, Sri Lanka, and the rest of the subcontinent is Daboia russelii. The very similar viper found in Myanmar, Thailand, southern China, Taiwan, and parts of Indonesia is Daboia siamensis, sometimes called the eastern or Siamese Russell's viper. Both are dangerous chain-patterned vipers of open and agricultural country, and both are major causes of snakebite, but their venoms differ, and antivenom made for one may not fully protect against the other.