Venomous snakebites are a common occurrence around the world, with about 5.4 million snake bites resulting in 2.7 million poisonings each year. While antivenom exists as an effective treatment, it is not always readily available or affordable in many parts of the world. This has led researchers to investigate various substances that could help neutralize snake venom when antivenom is not an option.
How does venom work?
Snake venom contains a complex mixture of proteins, peptides, and enzymes that have a variety of biochemical effects. The components of venom that are responsible for toxicity and death are:
- Neurotoxins – These affect the nervous system by blocking nerve signals and causing paralysis.
- Hemotoxins – Damages red blood cells, blood vessels, muscles, skin and kidneys.
- Cytotoxins – Destroys tissues and causes swelling.
- Cardiotoxins – Damages heart muscles.
When venom enters the human body via a bite, it quickly spreads through the lymphatic system and bloodstream. This allows toxins to circulate rapidly and cause systemic effects like paralysis, hemorrhage, necrosis, hypotension, and arrhythmias – all of which can lead to death in severe envenomings.
How does antivenom work?
Antivenoms are derived from antibodies produced by animals (typically horses or sheep) that have been exposed to snake venoms. The antibodies bind to and neutralize the venom toxins to prevent further poisoning.
Antivenom is administered intravenously, with dosage depending on the type of snake, severity of symptoms, and time elapsed since the bite. It works by:
- Binding to and neutralizing venom proteins/toxins.
- Distributing through the bloodstream and disabling circulatory toxins.
- Preventing the spread and progression of venom effects.
- Allowing recovery from toxicity.
However, antivenom is not universally effective against all snake venoms. Antivenoms are specific to different species and geographic locations – using an inappropriate antivenom can result in allergic reactions and treatment failure.
Natural substances that can help neutralize venom
In the absence of antivenom, researchers have been investigating various plant extracts, animal-derived compounds, and human antibodies that exhibit anti-venom properties. Though not proven to be substitutes for antivenom, some natural substances show promise in helping to neutralize venom.
Plant extracts
- Aristolochic acid – Found in the Aristolochia plant family, it inhibited venom from vipers and cobras in lab studies.
- Flavonoids – Antioxidants like quercetin and rutin neutralized venom phospholipase A2 and proteolytic enzymes in test tube experiments.
- Tannins – Polyphenols from teas and herbs precipitated proteins in snake venom during in vitro testing.
- Alkaloids – Compounds like morphine and nicotine were shown to counteract neurotoxicity, though they have their own side effects.
- Terpenes – Extracts from clove oil and eucalyptus inhibited hemolytic activity of rattlesnake venom.
While promising, most plant extracts have only been tested in the laboratory rather than clinical trials, so their safety and efficacy remains to be proven.
Animal-derived compounds
- Mongoose blood serum – Mongoose prey on venomous snakes; their blood contains protective proteins that neutralized viper venom toxins.
- Opossum serum – Opossums are resistant to pit viper venom; their serum showed anti-hemorrhagic effects against snake venom.
- Honey badger serum – This animal eats venomous snakes; its serum inhibited lethal and hemorrhagic activity of puff adder venom.
Blood serum from venom-resistant animals contains biomolecules that bind to and inhibit snake venom toxins. Some companies are developing anti-venom drugs based on these compounds.
Human antibodies
Antibodies naturally generated in human survivors of multiple venomous snakebites were found to have broad neutralizing effects against toxins from cobras, vipers, and rattlesnakes in lab tests. Researchers are studying techniques to isolate potent antibodies from such individuals to treat envenomation.
Other possible treatments
In addition to natural venom inhibitors, other treatments are also being researched:
- Monovalent antivenoms – Antibodies targeting specific toxins rather than whole venoms, to improve efficacy and safety.
- Small molecule inhibitors – Synthetic agents that block venom toxin activity.
- Metal chelators – Compounds that bind metals in venom and inhibit toxin enzyme function.
- Venom-degrading enzymes – Enzymes that break down venom proteins.
- Nanobodies – Camelid antibodies with high stability and toxin neutralization.
- Aptamers – Synthetic oligonucleotides that bind and inhibit toxins.
However, these are still in early research stages and not ready for clinical use.
Home remedies to avoid
There are many home remedies proposed for snake bites but most lack scientific evidence and some can even be harmful:
| Remedy | Reason to Avoid |
|---|---|
| Tourniquets | Can cut off blood flow and damage tissue |
| Incisions at bite site | Increases spread of venom rather than sucking it out |
| Cryotherapy | Ice or dry ice won’t decrease venom diffusion |
| Electroshock therapy | No evidence it destroys venom proteins |
| Suction devices | Don’t extract meaningful amounts of venom |
First aid should focus on washing the bite area, stabilizing and immobilizing the victim, and safely transporting them to a medical facility as soon as possible for antivenom therapy.
Conclusion
While various plant extracts, animal-derived compounds, and antibodies show promising ability to neutralize snake venom toxins, antivenom remains the only clinically proven treatment for envenomation. However, research continues into alternative therapies that could serve as adjuncts to antivenom or provide benefit when antivenom access is limited. Rapid first aid, supportive care, and proper antivenom remain key to surviving venomous snakebites.
