Snake Bite Defense: The Opossum

If you've been to rural Texas, as both Norbert and I have, there's a good chance you ran into a snake or two. I've nearly stepped on a few!

Up to two million people worldwide are bitten by snakes every year and many die. Now we're looking to an animal who can possibly help us ' the opossum; these guys are resistant to snake venom because a protein in their blood binds to the toxins and neutralizes them. Even though we've long known this, only recently did a scientist actually try synthesizing this protein to make an antivenom.

The problem with current antivenoms is that they're hard to make and expensive. Large amounts of venom first need to be milked from snakes, which is dangerous, then small amounts are injected into animals such as horses and pigs for about a year. The animals' immune systems react with antibodies which we harvest as antivenom. Each vial costs thousands of dollars and some people require twenty to thirty vials to treat a single snake bite.

If we could harness the protein in opossum's blood, it could provide a better alternative. The protein is Lethal Toxin Neutralizing Factor or LTNF and it also neutralizes the plant toxin ricin and toxins produced by sea cucumbers. Researchers were able to cheaply produce the active portion of LTNF and in large quantities.

Once isolated and purified, it was tested in mice and found to protect them against the venoms of western diamondback rattlesnakes and Russell's vipers. More testing is needed to see if it can become a universal antivenom and to make sure it's safe for humans. We've yet to understand just how this little protein is so effective.