SnakeBite Antivenom
SnakeBite Antivenom. The bite or sting of a highly venomous animal can inflict great suffering, including loss of limbs, paralysis, and extremely painful death. In the United States, envenomation (the injection of venom) usually happens during an encounter with a snake, spider, or insect.
Antivenom (often spelt “antivenin”) is an antibody product that can disable a particular venom’s toxins. If injected quickly after a bite or sting, the antibodies in antivenom neutralize the venom, potentially saving the victim’s life or limb.
Antivenom is still produced by much the same method that was developed in the 1890s to produce antitoxins for diphtheria and tetanus. An animal, such as a horse or goat, is injected with a small amount of venom. The antibodies released by the animal’s immune system to fight the damaging venom are later harvested via bleeding. The blood serum or plasma is then concentrated and purified into pharmaceutical-grade antivenom.
Although Antivenom can prevent venom-induced damage to a body, it is less able to reverse the damage already wreaked by the venom. Thus, it is important that antivenom treatment start as quickly as possible. Depending on the amount and toxicity of the venom, a victim may need many injections of antivenom to sufficiently neutralize the venom.
WHAT IS ANTIVENOM?
SnakeBite Antivenom are purified antibodies against venoms or venom components. Antivenoms are produced from antibodies made by animals to injected venoms. Antivenom is the only definitive treatment for effective bites by venomous Australian snakes. Prior to the availability of antivenom, death ensued in approximately 45% of tiger snake envenomations and more than 90% of taipan envenomations. The decision to use antivenom should be based on the patient’s history, examination and pathologic findings, and the type of antivenom used will depend on geographic, clinical and pathologic factors.
Snakebite envenoming
For more than 100 years, the mainstay of primary treatment for snakebite has been the administration of antivenoms. Antivenoms work by boosting our immune response after a snakebite. They are made by immunizing donor animals such as horses or sheep with snake venoms.
These animals have robust immune systems and produce powerful antibodies that can bind to snake venom components, enabling our own immune defences to eliminate these toxins. Antivenoms are obtained by harvesting and then purifying the antibodies from plasma produced by the donor animal. Good-quality antivenoms can literally make a difference between life and death.
Antivenom must be tailored to combat the venom of a particular species. The museum’s collection contains examples of antivenoms that were produced specifically to treat bites and stings of those venomous creatures endemic to the United States.
This ca 1940s snake-bite kit relies on first using a tourniquet to restrict the flow of venom from the wound into the bloodstream. An incision is then made with the scalpel to open the bite wound, and the glass syringe, with one of the rubber tips applied, is used to apply suction, with the intent of drawing out the venom. Kits like these are no longer recommended for use.
The French scientist Albert Calmette developed the first antivenom in 1895 (against the venom of the cobra). It would be another 30 years before antivenom was produced in the United States. In 1927, the H. K. Mulford Company of Philadelphia advertised that they were the first company licensed to produce and sell antivenom in the United States.
They had partnered with the Brazilian developer of the antivenom, Dr. Afriano does Amaral of the Antivenin Institute of America. Amaral supervised the collection and purification of venom from the Institute’s snakes. The venom was then sent to Mulford Laboratories, where it was injected into the company’s horses to produce the antivenom.
HOW IS ANTIVENOM MADE?
SnakeBite Antivenom is obtained from the various creatures in different ways. Snakes and funnel web spiders are milked for their venom. Stonefish, redback spider and box jellyfish antivenoms are made from venom extracted from the animal by dissection. This may be a dangerous process.
Small doses of venom or venom components are injected into the animal, and the dose gradually increased as the animal builds up a tolerance to the venom. In response to the introduction of the venom (a foreign substance), the animal produces antibodies to the venom. When the doses being injected are large, the amount of antibody produced is large.
Mulford’s Antivenin
This 1927 Mulford advertisement proclaims the company’s clear pride at being granted the first license to produce and sell antivenom in the United States. Courtesy of The Journal of the Florida Medical Association, Inc., August 1927, Vol. XIV, No. 2
Mulford’s initial antivenom product—Antivenin Nearctic Crotalidae—treated bites of North American pit vipers, including rattlesnakes, moccasins, and copperheads. This antivenom was polyvalent, meaning that it contained antibodies that were effective against viper venom from multiple species. In 1929, the museum collected a specimen of Antivenin Nearctic Crotalidae from the Mulford Company as part of an exhibition of new serum therapies.
In 1927, the Journal of the National Medical Association celebrated the introduction of Mulford’s North American pit viper antivenom, proclaiming, “A package of Antivenin should be included in every first-aid kit.” Mulford’s advertising materials claimed that antivenom was a necessary “insurance” for all those at risk of snake-bite, and warned that children at play, fishermen and hunters, farmers, civil engineers, and utility workers were all likely candidates for bites.
Horse blood inoculated with tiger and brown snake venoms
When injected into a patient, the binding sites on the antibody fragments bind to the venoms or venom components in the circulation and neutralize the activity of the venoms in the patient. Antivenoms have been made since the 1890s.
Australia was one of the first countries in the world to experiment with snake antivenoms, in 1898, when Frank Tidswell commenced immunization of a former ambulance horse with tiger snake (N. scutatus) venom.
CSL Ltd is the sole manufacturer of antivenoms for human use in Australia. Australian antivenoms are amongst the best in the world, in terms of purity and adverse reaction rate.
The company stated that children’s camps, military camps, and construction sites all had a duty to keep antivenom on hand. Antivenom was an exciting new technology that offered hope in the face of a common human fear. In 1930, the museum again collected from the Mulford Company for an exhibition illustrating the manufacture and use of “anti-snake-bite serum.”
By this time, the H. K. Mulford Company offered two additional varieties of snake antivenom. The first, Antivenin Bothropic, was another polyvalent antivenom created to neutralize the venom of South American pit vipers of the genus Bothrops. Bites from these snakes kill more people in the Americas than any other venomous snake. The second, Antivenin Cascabel, was treated envenomation by the South American cascabel, a tropical rattlesnake.
A Bothropic Antivenin kit from 1930. Mulford supplied its antivenom in pre-filled syringe kits to make treatments easy to transport and administer when one was far from medical attention. According to the kit’s directions, immediately following a snakebite, you must inject the entire contents of the syringe under the skin of your thigh or abdomen. Even better, a companion could inject you in the arm or between the shoulder blades.
Mulford Laboratories expanded into the spider bite business in 1936, when they produced an antivenom against Latrodectus mactans—the black widow spider.
A circa 1954 specimen of black widow antivenin from the Museum’s collection.
In the past few years, snakebite antivenom has been in the news, again. In states such as Texas and Florida, a shortage of coral snake antivenom has put medical providers in a disturbing position. Because they do not want to waste precious treatment, some doctors feel pressured to wait and see if a bite victim shows symptoms of envenomation before administering antivenom. However, the power of the treatment can be compromised by waiting.
Although the World Health Organization includes snakebite antivenom on its List of Essential Medicines, the world is experiencing shortages of antivenom. The populations hardest hit by the shortages tend to live and work in rural areas where highly venomous snakes are endemic, especially in less-developed nations with housing that allows for easier access by venomous snakes.
Hospitals currently face a multifaceted antivenom problem. Antivenom can be very expensive, a problem that is compounded when the product goes unused before its expiration date. Many clinics do not have sufficient training in selecting the correct antivenom or administering the treatment. The challenges do not stop there: patients can suffer serious allergic reactions to antivenom, and medical supervision during treatment is important.
New monoclonal antibody antivenoms that cause fewer allergic reactions are being developed. Like Mulford’s initial 1927 antivenom product, CroFab antivenom is an antidote to the venom of North American pit vipers, including rattlesnake, cottonmouth, and copperhead. However, because the CroFab product uses only a fragment of the cultured antibody, it causes fewer serious allergic reactions than older serum-based, whole antibody antivenoms.
Antivenom is one of those treatments that most of us never think about—until we suddenly and very desperately need it. The American Medical Association’s 1927 prediction that antivenom should be in every first-aid kit has not come to be. Contemporary antivenoms made under strict controls are very effective. Yet, they remain out of reach for many victims who most need them.
