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STAY AWAY: A copperhead, like the one pictured here, bit Oakley Yoder. The snake’s venom can cause serious damage.

AUDREY SNIDER-BELL/SHUTTERSTOCK.COM

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NGSS: Core Idea: PS1.B

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TEKS: 6.3D, 7.12A, 8.3D, B.5B, B.10A

Bitten!

When a venomous snake strikes, the right medicine can save a person’s life

September 23, 2019
By Kimberly Y. Masibay

AS YOU READ, THINK ABOUT what you would do if a snake were to bite you.

COURTESY OF JOSH PERRY

Two summers ago, 9-year-old Oakley Yoder from Indiana was having a great time at camp . . . right up until the moment when a copperhead sank its fangs into her foot. “It happened at dusk,” says Oakley. “I was on a trail in the woods with my group. We were hiking back from a rock climbing activity, and I felt like I stepped on something prickly.”

Oakley thought she might have been scratched by some thorns, but then searing pain shot through her right foot. She cried out to her counselors. They took one look at the pair of oozing puncture wounds on the girl’s toe and knew that Oakley had been bitten by a snake—a venomous one. Copperhead venom wreaks havoc on blood vessels and soft tissues of the body. In the minutes and hours after a bite, a victim will experience internal bleeding and a potentially lethal drop in blood pressure. Oakley had to get to a hospital, fast.

Doctors need to treat venomous snakebites swiftly with injections of antivenom. This medication can halt venom in its tracks and prevent it from harming a snakebite victim’s body any further. “As antivenom flows through the bloodstream, it finds molecules of venom and neutralizes them,” says Dr. Leslie Boyer. Boyer is a toxinologist—a scientist who studies the effects of venom. She was also the founding director of the VIPER Institute at the University of Arizona, which aims to learn more about how venoms work. “Unfortunately, antivenom cannot reverse damage that venom has already done,” says Boyer. So, to minimize the amount of time venom has to harm a victim’s body, it is urgent to treat a snakebite ASAP.

Two summers ago, 9-year-old Oakley Yoder from Indiana went to camp. She was having a great time . . . until a copperhead sank its fangs into her foot. “It happened at dusk,” says Oakley. “I was on a trail in the woods with my group. We were hiking back from a rock climbing activity, and I felt like I stepped on something prickly.”

Oakley thought some thorns might have scratched her. But then burning pain shot through her right foot. She cried out to her counselors. They took one look at the two oozing puncture wounds and knew what had happened. Oakley had been bitten by a venomous snake. Copperhead venom causes serious harm to blood vessels and soft tissues of the body. In the minutes and hours after a bite, a victim will bleed internally. Blood pressure can drop low enough to cause death. Oakley had to get to a hospital, fast.

Doctors need to treat venomous snakebites quickly. They use injections of antivenom. This medication can stop venom from harming the body further. “As antivenom flows through the bloodstream, it finds molecules of venom and neutralizes them,” says Dr. Leslie Boyer. Boyer is a toxinologist—a scientist who studies the effects of venom. She was also the founding director of the VIPER Institute at the University of Arizona. Its goal is to learn more about how venoms work. “Unfortunately, antivenom cannot reverse damage that venom has already done,” says Boyer. So it’s important to treat a snakebite as soon as possible. That way, venom has less time to harm a victim’s body.

CHEMICAL WEAPON

Venom is a chemical cocktail that some snakes—including pit vipers such as copperheads—produce to take down prey. Venoms contain a mixture of poisonous molecules called toxins. When a snake injects venom into another animal, the toxins circulate through the prey’s body and prevent it from functioning properly. The fast-acting substances can immobilize, kill, or even begin to digest the prey, leaving it no chance to escape.

Apart from venom, snakes don’t have many other weapons they can use to catch a meal. They can’t slither particularly fast to give chase. They can’t pin down prey with mighty jaws or seize prey with powerful talons or claws. But snakes can strike amazingly fast—some are able to bite their victim two times in the blink of an eye.

Some snakes, including pit vipers such as copperheads, produce venom. They use this combination of chemicals to take down prey. Venoms contain a mixture of poisonous molecules called toxins. A snake injects venom into another animal. Then the toxins flow through the victim’s body and prevent it from working properly. These chemicals can stop, kill, or even begin to digest prey. The toxins act fast, before the animal has a chance to escape.

Besides venom, snakes don’t have many weapons for catching a meal. They can’t slither very fast to give chase. They can’t pin down prey with mighty jaws. And they can’t grab it with powerful talons or claws. But snakes can strike with amazing speed. Some can bite their victim twice in the blink of an eye.

HOW ANTIVENOM IS MADE

Scientists enlist the help of snakes, as well as livestock, like horses, that live on specialized ranches, to make medicines that treat dangerous snakebites. If administered quickly, these antivenoms can save people’s lives.

Scientists enlist the help of snakes, as well as livestock, like horses, that live on specialized ranches, to make medicines that treat dangerous snakebites. If administered quickly, these antivenoms can save people’s lives.

DAMIEN SCOGIN

A technician extracts and later purifies venom from the species of snake for which scientists want to make an antivenom.

A technician extracts and later purifies venom from the species of snake for which scientists want to make an antivenom.

A worker injects a small, harmless dose of venom into a horse. That triggers the horse’s immune system to produce molecules, called antibodies, that disable toxins in the venom.

A worker injects a small, harmless dose of venom into a horse. That triggers the horse’s immune system to produce molecules, called antibodies, that disable toxins in the venom.

Over the next year, the horse receives several injections, containing increasing amounts of venom. Eventually, the horse produces so many antibodies that it becomes immune to the venom.

Over the next year, the horse receives several injections, containing increasing amounts of venom. Eventually, the horse produces so many antibodies that it becomes immune to the venom.

Once the horse’s antibody level peaks, a worker draws blood from the horse and separates out the plasma, the part of the blood that contains the antibodies.

Once the horse’s antibody level peaks, a worker draws blood from the horse and separates out the plasma, the part of the blood that contains the antibodies.

The plasma is sent to a lab where chemists process and package it as a liquid or freeze-dried powder. It’s then shipped in vials to hospital pharmacies.

The plasma is sent to a lab where chemists process and package it as a liquid or freeze-dried powder. It’s then shipped in vials to hospital pharmacies.

When a patient comes to the ER with a snakebite, doctors use an IV to inject the antivenom into the person’s vein. Antibodies circulate through the body and neutralize the venom toxins.

When a patient comes to the ER with a snakebite, doctors use an IV to inject the antivenom into the person’s vein. Antibodies circulate through the body and neutralize the venom toxins.

HOW ANTIVENOM IS MADE

Scientists enlist the help of snakes, as well as livestock, like horses, that live on specialized ranches, to make medicines that treat dangerous snakebites. If administered quickly, these antivenoms can save people’s lives.

Scientists enlist the help of snakes, as well as livestock, like horses, that live on specialized ranches, to make medicines that treat dangerous snakebites. If administered quickly, these antivenoms can save people’s lives.

DAMIEN SCOGIN

A technician extracts and later purifies venom from the species of snake for which scientists want to make an antivenom.

A technician extracts and later purifies venom from the species of snake for which scientists want to make an antivenom.

A worker injects a small, harmless dose of venom into a horse. That triggers the horse’s immune system to produce molecules, called antibodies, that disable toxins in the venom.

A worker injects a small, harmless dose of venom into a horse. That triggers the horse’s immune system to produce molecules, called antibodies, that disable toxins in the venom.

Over the next year, the horse receives several injections, containing increasing amounts of venom. Eventually, the horse produces so many antibodies that it becomes immune to the venom.

Over the next year, the horse receives several injections, containing increasing amounts of venom. Eventually, the horse produces so many antibodies that it becomes immune to the venom.

Once the horse’s antibody level peaks, a worker draws blood from the horse and separates out the plasma, the part of the blood that contains the antibodies.

Once the horse’s antibody level peaks, a worker draws blood from the horse and separates out the plasma, the part of the blood that contains the antibodies.

The plasma is sent to a lab where chemists process and package it as a liquid or freeze-dried powder. It’s then shipped in vials to hospital pharmacies.

The plasma is sent to a lab where chemists process and package it as a liquid or freeze-dried powder. It’s then shipped in vials to hospital pharmacies.

When a patient comes to the ER with a snakebite, doctors use an IV to inject the antivenom into the person’s vein. Antibodies circulate through the body and neutralize the venom toxins.

When a patient comes to the ER with a snakebite, doctors use an IV to inject the antivenom into the person’s vein. Antibodies circulate through the body and neutralize the venom toxins.

Venomous snakes don’t target humans, but if the reptiles feel threatened by a person, they will lash out. Most snakebites happen when someone accidentally steps on a snake, like Oakley did, and the snake then strikes in self-defense. Every year, venomous snakes bite 8,000 to 10,000 people in the U.S., according to the Centers for Disease Control and Prevention. About 5 to 15 of those victims die (see Know Your Snakes).

Every venomous snake species produces a slightly different poisonous concoction that’s specially adapted to disable its preferred food, usually small animals. Snake venom can be a triple threat: it can have necrotizing (causing tissue death), anticoagulant (preventing blood from clotting), and neurotoxic (damaging to nerves) properties. Fortunately, the venom of the copperhead that Oakley stepped on didn’t contain neurotoxins, which are the most deadly compounds in venom. It did, however, contain chemicals that could destroy soft tissue and cause uncontrolled bleeding. The girl likely wouldn’t die from the bite—but there was a chance she could lose her foot.

Venomous snakes don’t target humans. But if the reptiles feel threatened by a person, they will strike. A person may step on a snake by mistake, like Oakley did. Then the snake strikes in self-defense. That’s how most snakebites happen. Every year, venomous snakes bite 8,000 to 10,000 people in the U.S., according to the Centers for Disease Control and Prevention. About 5 to 15 of those victims die.

Every venomous snake species produces a slightly different poisonous mixture. Each species’ venom is just right to take down its favorite food, usually small animals. Snake venom can be a triple threat. It can have necrotizing effects, causing tissue death. It can have anticoagulant effects, preventing blood from clotting. And it can damage nerves with neurotoxic effects. Fortunately, the venom of the copperhead that bit Oakley didn’t contain neurotoxins. Those are the deadliest compounds in venom. But it did contain chemicals that could destroy soft tissue and cause heavy bleeding. Oakley likely wouldn’t die from the bite. But there was a chance she could lose her foot.

TREATING TOXINS

COURTESY OF JOSH PERRY

It was nearly midnight when the phone rang and jolted Oakley’s mother, Shelli, awake. The voice on the other end of the line said that Oakley was being rushed by helicopter from the remote wilderness camp to a hospital. For a moment, Shelli thought she was dreaming, but this was no dream. It was a real-life nightmare.

When Oakley reached the emergency room, doctors injected her with four vials of the antivenom CroFab, the drug most commonly used by U.S. hospitals for pit viper bites. Then she was rushed by ambulance to a children’s hospital, her toe still oozing and bruised, where her parents were anxiously waiting.

“When I saw Oakley arrive on the stretcher, her entire leg was swollen,” recalls Shelli. “She asked me, ‘Will I ever walk again? Am I going to lose my leg? Am I going to die?’” Doctors assured Oakley that she wasn’t going to die and that her foot would eventually be fine.

Less than 24 hours after the snakebite, Oakley was able to go home with her parents. The antivenom saved her foot by halting the damage caused by the venom before it got too extreme. Oakley spent the rest of the summer taking it easy so her foot could recover. Meanwhile, as her parents were also recovering from the shock of their lives, they received another one: the medical bill.

The total for Oakley’s care—including the helicopter and ambulance rides and hospital and physician fees—was nearly $150,000. The price tag for the four vials of antivenom alone was $67,957. “When I saw that number, it really took my breath away,” says Oakley’s father, Joshua. Fortunately, with great time and effort, Oakley’s parents managed to negotiate the bill down.

But even after the haggling, the antivenom Oakley received still cost a lot. A single box of CroFab, one of only two pit viper antidotes available in the U.S., contains two vials of antivenom. It can cost a hospital pharmacy nearly $7,000. It’s expensive because making and distributing antivenom is a complicated process.

It was nearly midnight. The phone rang and woke Oakley’s mother, Shelli. The voice on the other end of the line had terrible news. Oakley was being rushed by helicopter from the remote wilderness camp to a hospital. At first, Shelli thought she was dreaming. But this was no dream. It was a real-life nightmare.

When Oakley reached the emergency room, doctors acted fast. They injected her with four vials of the antivenom CroFab. It’s the drug most commonly used by U.S. hospitals for pit viper bites. Then an ambulance rushed her to a children’s hospital, with her toe still oozing and bruised. Her worried parents were waiting there.

“When I saw Oakley arrive on the stretcher, her entire leg was swollen,” says Shelli. “She asked me, ‘Will I ever walk again? Am I going to lose my leg? Am I going to die?’” But doctors had good news for Oakley. She wasn’t going to die, and her foot would be fine, in time.

Less than 24 hours after the snakebite, Oakley was able to go home with her parents. The antivenom saved her foot. It stopped the damage from the venom before it got too extreme. For the rest of the summer, Oakley took it easy so her foot could recover. Her parents were also recovering from the shock of their lives. Then they received another one. It was the medical bill.

The total for Oakley’s care was nearly $150,000. That included the helicopter and ambulance rides and hospital and doctor fees. Just the four vials of antivenom cost $67,957. “When I saw that number, it really took my breath away,” says Oakley’s father, Joshua. Luckily, Oakley’s parents worked out an agreement to bring the bill down. That took great time and effort.

But even with the agreement, the antivenom Oakley received still cost a lot. CroFab is one of only two pit viper antidotes used in the U.S. One box of it contains two vials of antivenom. The box can cost a hospital pharmacy nearly $7,000. Making and supplying antivenom is complicated. That’s why the drug is so expensive.

KNOW YOUR SNAKES

An estimated 24 species of venomous snakes live in North America. One or more of these species can be found in every state in the U.S., except Alaska. Here are some to look out for.

An estimated 24 species of venomous snakes live in North America. One or more of these species can be found in every state in the U.S., except Alaska. Here are some to look out for.

MYN/PAUL MARCELLINI/NATUREPL

CORAL SNAKES: STRONGEST VENOM, LEAST TISSUE DAMAGE

Coral snake venom is mostly neurotoxic, so it doesn’t damage soft tissues like pit viper venom does. The venom harms the nervous system, though, which can result in a shutdown of the respiratory system. Victims need treatment before potentially lethal weakness sets in.

CORAL SNAKES: STRONGEST VENOM, LEAST TISSUE DAMAGE

Coral snake venom is mostly neurotoxic, so it doesn’t damage soft tissues like pit viper venom does. The venom harms the nervous system, though, which can result in a shutdown of the respiratory system. Victims need treatment before potentially lethal weakness sets in.

SHUTTERSTOCK.COM

WATCH OUT! Can you see the snake in this picture?

COPPERHEADS: MOST BITES BUT FEW DEATHS

Copperheads are camouflaged to help them blend almost invisibly into their surroundings. That’s why, every year, thousands of hikers accidentally step on them—and get bitten. Their venom is the least toxic of the North American venomous pit vipers, though, so they rarely kill people.

COPPERHEADS: MOST BITES BUT FEW DEATHS

Copperheads are camouflaged to help them blend almost invisibly into their surroundings. That’s why, every year, thousands of hikers accidentally step on them—and get bitten. Their venom is the least toxic of the North American venomous pit vipers, though, so they rarely kill people.

SHUTTERSTOCK.COM

RATTLESNAKES: MOST VARIETY

North America is home to 16 to 20 different rattlesnake species, ranging from the tiny pygmy to the fierce diamondback. Large, willing to strike, and potently venomous, the diamondback is definitely a snake to avoid. Its venom causes severe tissue damage and, in the worst-case scenario, can even kill a person.

RATTLESNAKES: MOST VARIETY

North America is home to 16 to 20 different rattlesnake species, ranging from the tiny pygmy to the fierce diamondback. Large, willing to strike, and potently venomous, the diamondback is definitely a snake to avoid. Its venom causes severe tissue damage and, in the worst-case scenario, can even kill a person.

KNOW YOUR SNAKES

An estimated 24 species of venomous snakes live in North America. One or more of these species can be found in every state in the U.S., except Alaska. Here are some to look out for.

An estimated 24 species of venomous snakes live in North America. One or more of these species can be found in every state in the U.S., except Alaska. Here are some to look out for.

MYN/PAUL MARCELLINI/NATUREPL

CORAL SNAKES: STRONGEST VENOM, LEAST TISSUE DAMAGE

Coral snake venom is mostly neurotoxic, so it doesn’t damage soft tissues like pit viper venom does. The venom harms the nervous system, though, which can result in a shutdown of the respiratory system. Victims need treatment before potentially lethal weakness sets in.

CORAL SNAKES: STRONGEST VENOM, LEAST TISSUE DAMAGE

Coral snake venom is mostly neurotoxic, so it doesn’t damage soft tissues like pit viper venom does. The venom harms the nervous system, though, which can result in a shutdown of the respiratory system. Victims need treatment before potentially lethal weakness sets in.