People who handle or keep poisonous snakes have to consider that at some point, whether or not it is their fault, they might get bit. Getting antivenom to deal with the ensuing poisoning however, may not be a simple prospect. If the patient is not given the appropriate antivenom for that particular snake’s venom, the cure may be ineffective or make matters worse. Creating antivenom is no easy process. It is also expensive and to some, controversial. Antivenom has been available, however, for more than 100 years and is still primarily made the same way as the first time.
In the 1890s Albert Calmette, who was a protégée of Louis Pasteur, found himself in a troubling situation. He was living in what is now Vietnam and his village near Saigon had just suffered a serious flood. The water wasn’t the worst of it. The flooding pushed monocled cobras into village where they bit at least 40 people and killed four. After this experience Calmette began work on a cure that would be similar to the then new science of vaccinations. Calmette eventually caught snakes, “milked” them of their venom and injected it into horses to create antibodies. Drawing the horses’ blood for a serum, he was able to create an antivenom that worked on humans.
How to Make Antivenom
Today the process of creating antivenom is carefully controlled, but essentially done the same way. Snakes are kept in quarantine to make sure they are healthy and then caught up. The snake’s fangs are pushed through a thin layer of plastic covering a vial. Then its glands are gently squeezed in order to empty the snake’s store of venom into the vial. However, this is still only a minute amount of venom and snakes must be milked numerous times in order to get a workable amount of venom. The venom is then frozen and freeze-dried for transport.
The next step is to inject small amounts of venom into an animal that can create antibodies. Horses have often been used, but many people are allergic to the horse-based antivenom. So sheep and goats are also used frequently. A veterinarian looks over the process, checking on the animal’s well-being and it takes 8 to 10 weeks for antibodies to peak in the animal’s bloodstream. Then the animal has blood drawn, which is placed in a centrifuge and the plasma separated out. From here the antivenom is separated out and lastly enzymes are used to break down the antibody into small parts and isolating its active ingredient. Once this is completed, it still has to be deemed safe and effective by the FDA.
Today producing antivenom remains prohibitively expensive. CroFab, the only FDA-licensed antivenom produced in the United States is used to treat all North American species except for the coral snake, yet its effectiveness can vary depending on species and location. There is also an issue of demand, of which there is very little. Recently the manufacturer of coral snake antivenom ceased production. The current stockpile expired and upon inspection the FDA extended its expiration. This still leaves a question of how much longer the supply will last. Chances are that once it is gone there will be no FDA approved source in the United States. While the process of creating antivenom has changed very little, the cost has skyrocketed; meaning that best thing to do is just to avoid getting bit.
All the same, avoiding contact with snakes simply is not an acceptable choice to some people, especially those who live in the Animal Underworld. Whether venomous snakes are collected for pleasure, for food or for medicine, there are still people who are willing to risk a bite. Henry Rollins meets some of these people in Animal Underworld: Wild Hunger.
Tune in to the three-part series Animal Underworld Monday, May 28th starting at 8P et/pt.