Venomous snakes, which include cobras, vipers, and rattlesnakes, can pose a significant danger to humans. In the United States, around 7,000 – 8,000 people are bitten by venomous snakes per year and, of these, around five individuals die as a result of the snake bite. However, the incidence of snake bites and deaths is much higher worldwide with an estimated 1.8 – 2.7 million bites and 82,00 – 137,000 deaths each year.
Bites from venomous snakes may lead to a variety of medical emergencies such as severe paralysis that impairs breathing, the destruction of skin and muscle tissue that can result in limb amputation, bleeding disorders that may lead to hemorrhage, and kidney failure. Importantly, highly effective treatments for snake venom exists in the form of anti-venom.
One problem faced during the development of effective anti-venoms is the ensuring that the anti-venoms can counteract bites from more than just one species of snake. Traditional methods of creating anti-venom (as shown in the video below) include immunizing animals, typically horses, with small doses of a single snake venom repeatedly until the horse develops antibodies against the venom. The antibodies are then extracted from the horse and purified for use in humans. As stated above, one issue with this method is that it is impossible to control the specificity and potency of anti-venoms against specific toxins.
In a recent study published in the Proceedings of the National Academy of Sciences, a research team from the University of Maryland detailed their findings on a single protein that could inhibit a variety of snake venom toxins.
The study investigated how rattlesnakes protect themselves from their own venom. Indeed, snake venom toxins can be harmful to snakes themselves if the toxins enter the snake’s tissue or circulatory system during feeding or digestion. As such, many venomous snakes have evolved an autoresistance to their own toxins. Dr. Sean Carroll, the senior author on the study said, “To survive a venomous snake bite, prey have to evolve resistance to the venom. If the prey become a little resistant, then the snakes have to adjust with a better venom. But snakes have also been able to protect themselves from their own evolving venom.”
To understand how this happens, the researchers investigated a family of proteins that have been previously attributed to venom-resistance. They found that a single protein in this family, called FETUA-3, was present in the genome of many venomous snakes. And in further testing, FETUA-3 was found to inhibit a wide range of snake venom toxins.
The researchers hope that their results will help drive research into more effective snake bite treatments. The lead researcher on the study, Dr. Fiona Ukken, said of their research, “by improving our understanding of the molecular basis of venom inhibition, we can help create novel and more effective therapeutic treatments.”
Sources: CDC; World Health Organization; PNAS
