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Venom Rx

Venom may be deadly, but it can also be the source of medical cures. As NATURE's AUSTRALIA'S LITTLE ASSASSINS shows, for instance, scientists often need a snake's or spider's venom to begin developing an antivenom. It works like this:

A researcher carefully extracts venom from the snake or spider -- sometimes by getting it to "bite" a piece of cloth stretched across a collecting bottle.
Technicians purify, dry, and freeze the venom.
A weakened solution of the venom is injected into a horse, pig, or other animal, which produces immune-system cells called antibodies in reaction. In essence, the animal becomes a drug factory.
The antibodies are extracted from the animal's blood, then processed into the antivenom.
When a bite victim arrives at the hospital, doctors inject the antivenom, helping the body's own immune system ward off the poison. Physicians have to be careful, however, since some people can react badly to antivenom.

Antivenom isn't the only medical use of venom. Researchers also study venom because it contains dozens of substances that may be of medicinal value.

At the University of Buffalo, New York, for instance, a protein isolated from the venom of a Chilean tarantula is being used to develop a new drug to treat atrial fibrillation, the chaotic beating of the heart that is a major cause of death following a heart attack. The work is an unexpected outgrowth of basic studies of the venom. "No one in their right mind would have sought to block atrial fibrillation with spider spit," says Frederick Sachs, a professor of physiology and biophysics.

Similarly, at the University of California, Irvine, researchers used studies of snake venom and poison frog proteins to uncover chemicals that might help treat stomach disorders. Australia's toxic cone snail, meanwhile, produces a chemical that may be a valuable pain killer. And the humble bumble bee's sting might one day yield a drug that reduces inflammation.

Don't look for these venom-based drugs on your supermarket shelves just yet, however. Most are many years from reaching the market, and some may never make it through safety trials.

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