Mexico To The Rescue In America's 'Venom Belt'

Aug 6, 2011

Toxicologists refer to the American Southwest as the "Venom Belt" for its many venomous spiders, snakes and scorpions. In fact, doctors estimate there are about 250 severe scorpion stings a year in this country.

Most of those stung are children in Arizona, but the U.S. ran out of its own supply of scorpion antivenom nearly a decade ago. Mexican doctors, however, have been treating stings from venomous creatures for years, and what they've learned may now save American lives.

Just last week, the Food and Drug Administration approved a new drug made in Mexico for use in the U.S. to treat severe scorpion stings. It's called Anascorp and was developed by a company called Instituto Bioclon.

The Scorpion Sting Experts

"Without antivenom, if you've got that bad of a sting, you accept intensive care or you risk death," says Dr. Leslie Boyer, a pediatrician who directs a venom research center in Tucson.

Drug companies in the U.S. have little incentive to make antivenom, because it's expensive and there simply aren't enough patients to guarantee a profit. "We in Arizona felt very isolated; we felt abandoned," Boyer says. "This was an orphan disease."

That was until Boyer took a trip south of the border and discovered that Mexico has a far bigger scorpion problem.

In Mexico, a quarter of a million people are stung by scorpions each year. Some clinics in central Mexico can have dozens of scorpion sting patients per night in the summer.

"Mexico has been in the antivenom field for many years, and over many years we have accumulated a big experience on how to make good antivenoms," says Dr. Alejandro Alagon, a professor of biochemistry at Mexico's Autonomous National University.

Alagon says 20 years ago hundreds of people in Mexico would die each year from scorpion stings. Alagon is also an adviser to the Mexican drug company that makes the antivenom, which is effective against the same species of scorpion that exists in Arizona.

Bringing The Antivenom Over The Border

"We discovered that our Mexican colleagues had pushed the technology of antivenom development way beyond what we had done in the U.S.," Boyer says.

In 2004, Boyer launched a clinical study of Anascorp in the U.S. The study, supervised by the FDA, included 28 participating hospitals. Nearly 2,000 Americans received the drug.

One of the youngest American patients to receive it so far is 4-year-old Ryleigh Wagley. She was stung by a scorpion in her crib when she was just 25 days old.

The Wagley family lives in rural eastern Arizona, more than two hours away from the nearest ICU. Luckily for Ryleigh, a small clinic in the nearby mining town of Morenci was part of the clinical study of Anascorp. Dr. Fred Fox, the physician who treated Ryleigh, says the antivenom helped saved her life.

"It's allowed us to treat patients who either could have died or been seriously ill and would have been sent to the intensive care unit," Fox says. "Now we can treat them and actually send them home from here."

Scorpion stings are only one problem, however. Across the U.S., there is a severe shortage of antivenom against all kinds of venomous animals from spiders to snakes. Currently, hospitals across the country are testing two more drugs from Instituto Bioclon. One is an antivenom to treat black widow spider bites; the other, to treat rattlesnake bites.

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