Supplies of North American coral-snake antivenin are almost non-existent since the only manufacturer shut down its operations several years ago, but an Arizona group is taking the lead on finding a solution.
Coral-snake venom is more potent than a rattlesnake’s, and the shortage of antivenin could pose a danger, particularly in the Southeast, where the most dangerous species of coral snake lives.
The University of Arizona Viper Institute is leading an investigation with the Mexican company Bioclon Institute into a new antivenin that they hope will meet Food and Drug Administration
standards.
The FDA-approved Micrurus fulvius, known by the popular name “Antivenin,” is expected to expire and run out by September or October.
It was produced by Wyeth Pharmaceuticals and distributed by Pfizer Inc., but because it was so rarely used, production was halted. The remaining supply was due to expire on Oct. 31, 2008, but the FDA extended it twice. The antivenin expiration date could be extended once more.
There is no other current U.S.-licensed supplier, and because of the unpredictability of where coral-snake bites occur, regional and local shortages could happen sooner, according to the FDA website.
FDA spokeswoman Shelly Burgess said it was still too early to tell when the agency would be able to find a replacement, but it is trying to make existing antivenin last as long as possible.
Bioclon Institute, a pharmaceutical and biological company in Mexico City, has developed an antivenin, but it has a ways to go before it receives FDA approval.
Over the next four years, the Viper Institute and Bioclon will use an FDA grant for $1.6 million to get Bioclon’s antivenin up to standard, but Boyer said it could take 10 years for approval.
“That is far less than the actual cost of a study that covers such a wide geographic area,” Viper Institute Director Leslie Boyer said. “It will be years before we know if this antivenom works as well as we hope.”
There are three species of coral snakes in the country. The most dangerous species can leave someone so weak that the diaphragm becomes paralyzed and the victim needs help breathing. The antivenin must be administered before paralysis sets in and can be effective because the effects of a bite may not appear until up to seven hours later.
The Arizona coral snake is the least threatening of the three species and in fact, with its small size, short teeth and shy nature, isn’t much of a threat at all.
There have never been any reported deaths in Arizona from a coral-snake bite and typically there are only five cases of coral-snake bites in a year, Boyer said.
However, “it’s a completely different story in Texas and in the Southeast,” ASU School of Life Sciences associate professor Dale DeNardo said. “That’s a big snake that can cause some serious health concerns.”
Arizona coral snakes are typically the diameter and length of a pencil, DeNardo said. He describes the snakes as secretive and docile creatures. Because they live in burrows underground, even DeNardo, who works as a field biologist, has rarely seen them.
Arizona coral snakes have short teeth, not fangs like rattlesnakes. DeNardo said it’s questionable if a bite would even penetrate the skin and if it did, the snake injects only a small amount of venom.
King snakes, shovel-nosed snakes and banded-sand snakes are often mistaken for the red, yellow and black Arizona coral snake.
The situation may be different for animals. Because Arizona coral snakes eat other reptiles and snakes, their venom poses more of a threat to those animals.
Owners whose pets are bitten should bring them to a veterinarian, which Mesa City Animal Control supervisor Diane Brady recommends. Boyer said dogs and cats should not have any long-term effects from a bite because of the snake’s size.
Brady said she doesn’t get many calls on Arizona coral snakes. “Most of our snake calls are rattlesnakes, gopher snakes or what people think are coral snakes but turn out to be king snakes,” Brady said. “We have not had a report of anyone being bitten by a (coral) snake in years.”
Boyer said that while Arizona doesn’t have much to worry about, her research will help people in other parts of the country, as well as the occasional exotic pet owner who may get bitten.
“Right now for Arizona there are just two messages that are important: One, our coral snakes are not the dangerous ones, so Arizonans don’t have to be worried. Two, however, Arizona is going to take the lead in a solution for the U.S.”