ASU Research E-Magazine: A Furry Factory Against Scary Scorpions

Pamela is a regular blood donor, just like millions of Americans. In fact, she has donated more than eight gallons of blood during her 15-year career. Pamela’s donations have saved lives.

Another Red Cross volunteer? Another conscientious citizen? Not quite. Pamela is a goat. She also is a bioengineering marvel that might save your toddler’s life. You see, Pamela’s job involves saving people from scorpions.

Pamela works for the Antivenin Production Laboratory at Arizona State University. She specializes in manufacturing an antivenin. Scorpion antivenin is a medicine used to combat the potentially life-threatening effects of a bark scorpion’s stings.

Bark scorpions (Centruroides sculpturatus or Centruroides exilicauda) are tiny desert creatures that pack a big punch. Their sting brings pain and numbness. The sting is also potentially deadly. In Mexico, for example, people—mostly small children—still die each year after being stung by scorpions.

But in Arizona, there has not been a single documented scorpion sting-related death for more than 30 years. Work by Pamela and her anti-venin producing ancestors is partly responsible for that happy record.

Pamela’s boss is Marilyn Bloom. Bloom is an ASU research specialist who specializes in immunology.

According to the Arizona Poison Control Center, nearly 5,000 people get stung by scorpions each year in Arizona. Most stings occur in Phoenix, Tucson, and other metropolitan areas where rapid growth continues to displace the 36 species of scorpions that call Arizona and the Sonoran Desert home.

Bark scorpions are the most common Phoenix-area sting offenders. Unfortunately, bark scorpions also are the only species of Arizona scorpion considered “potentially medically important,” or potentially fatal, according to Bloom. Those facts amount to a good news-bad news scenario.

The good news is that bark scorpions are only found in Arizona, Mexico, and a fringe area of New Mexico. Here in the United States, at least, antivenin is readily available.

The bad news is that nearly five percent of all people who get stung by bark scorpions suffer severe reactions to the sting. Those reactions can be life threatening, especially in young children or elderly victims.

A common scenario might unfold as follows. A cheerful toddler transforms into a child who is racked with pain. Her eyes or face begin to twitch. Her limbs go numb. Swallowing becomes increasingly more difficult. The child may vomit. As tiny eyes roll back into her head, the parents panic. They remain absolutely clueless as to the cause of all this pain.

There is neither swelling nor a mark where the child was stung.

They do not know it yet, but the parents owe Pamela the ASU goat a debt of gratitude.

Pamela the goat and Marilyn Bloom work together to produce an antivenin that helps save the lives of people who have been stung by a scorpion

Antibodies created by her body and processed from her blood into an antivenin serum await the sting victim at the hospital. The antivenin is stored in tiny five-milliliter vials.

One of the tablespoon-sized amounts of antivenin will be injected into the child. Twenty or 30 minutes later, the terrorized toddler will almost certainly start transforming back into a cheerful child. If not, a second dose will do the trick. The child should be able to go home the same day.

Bloom and Pamela create antivenin in partnership. Bloom provides the expertise, Pamela the biological magic.

The process begins when Bloom injects Pamela with a small, diluted dose of bark scorpion venom. Bloom knows that the doses she gives Pamela must be very small because bark scorpion venom is a neurotoxin. Neurotoxins are poisonous proteins that attack the nervous systems of both animals and humans.

By injecting only a small, oil-diluted dose of venom, Bloom ensures that Pamela does not suffer the same painful effects as a normal sting victim.

Bloom further protects Pamela by injecting the venom into her muscle. Since neurotoxins spread quickly through the series of nerves located just under the skin’s surface, they tend to shock the system when they hit. Injecting the venom deeper into muscle slows the rate it is absorbed by the goat’s body. Bloom’s precautions allow Pamela’s body to process the venom gradually.

Bloom typically injects Pamela once a week for about four weeks. The goat’s body reacts to the venom—which is known as an antigen, or unfamiliar protein—by producing antibodies.

Antibodies are the product of an immune system reaction similar to the reaction that happens when humans are given a flu shot or other type of vaccine. Pamela’s immune system automatically manufactures the antibodies to protect itself against the venom’s neurotoxins. The antibodies circulate through her bloodstream.

After several weeks and many injections, enough antibodies are present in Pamela’s blood to begin the sequence of donations. Bloom draws a cup of blood in a process that is similar to a human blood donation, then races with the sample to her lab.

In the laboratory, the collected blood is allowed to clot. Allowing the blood to clot makes it easier to separate the solid red and white blood cells from the serum, or liquid part of blood. The serum contains the antibodies to bark scorpion venom.

Bloom uses a centrifuge to spin the blood sample at very high speed. During the centrifuge process, Pamela’s blood separates into its solid and liquid parts. The pure goat serum is then filtered, sterilized, bottled, and frozen.

Bloom repeats this process once a week for several weeks each winter. Pamela and three other special ASU goats are the lifesaving donors.

Once enough serum has been made to meet the pending seasonal demand, Bloom sends it to a medical laboratory for packaging. The goats and Bloom’s handiwork will be in Arizona hospitals and clinics by early March—just in time for the onslaught of warm weather-related stings. —Lindsey Michaels