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Dallas Zoo ready to answer call when exotic snakes bite

By , DaLLAS MORNING NEWS

When an area man was bitten by an African bush viper, the Dallas Zoo was ready to strike.

Along with one of the country's most impressive collections of venomous snakes, the zoo also has one of the largest supplies of antivenom.

Most snakebites involve native species and bad judgment, jokes Bradley Lawrence, the zoo's reptile and amphibian supervisor.

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"Most of the time it's native venomous snakes that somebody has decided to mess around with, late at night, probably because they've had a few too many," he said. "Like, 'Oh, look, there's a snake. Let's pick it up!' "

Native snakes' antivenom is stocked in hospitals, but when someone in the Southwest, from Louisiana to California, needs an antidote for an exotic snakebite, the zoo is often called to help.

Ruston Hartdegen, the zoo's curator of herpetology, said such a call may come only once a year, but Lawrence said they often come about 3 a.m., and he is usually the person who answers.

Quick delivery

The zoo will deliver at least half of its supply of the necessary antivenom through police or CareFlite, which carries the vials by helicopter or plane.

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The hospitals that receive the antivenom pay to restock whatever isn't returned.

The zoo keeps thousands of vials - about $200,000 worth - in a refrigerator.

The most recent call for help came in January, when a man in the Dallas-Fort Worth area was bitten by his African bush viper, an exotic species without its own antivenom.

In such cases, the zoo sends an antivenom that scientific papers have shown could work, Lawrence said.

The African bush viper is illegal to own in Dallas and Fort Worth, but "laws are always broken," said Mark Pyle, president of the Dallas-Fort Worth Herpetological Society.

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The Texas Parks and Wildlife Department sells controlled exotic snake permits for venomous snakes and five of the constrictor species for $20 for recreational owners and $60 for commercial permits. But cities often ban the possession of venomous snakes, wildlife permits specialist Megan Russell said.

But she said the number of permits issued doesn't reflect the number of people who own venomous snakes without following the rules.

'Snakebite Center'

Typically anyone bitten by such a snake in the Dallas area is treated at Parkland Memorial Hospital - which senior toxicology fellow Dr. Nancy Onisko calls "the Snakebite Center of Excellence."

Parkland doesn't treat many exotic snakebites. In 2014, it treated one or two - compared with about 50 bites involving native species such as copperheads and rattlesnakes.

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For bites from copperheads, rattlesnakes and other native species, hospitals stock the antivenom CroFab.

When treating a bite, doctors determine the kind of snake involve and familiarize themselves with the venom's effects, the best antivenom to use and the risks. Some people can be allergic to antivenom, which is made by a few national suppliers.

If the potential for pain isn't enough of a reason to stay away from venomous snakes, the cost for bite treatments should be.

Prices for antivenom - before a hospital's markup - range from $200 a vial for Asian snakes to $2,500 a vial for Australian species.

Therapy usually begins with four to six vials, but up to 30 vials may be needed in extreme cases.

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