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Snake Venom
Paradoxically, the primary function of the venom or toxic secretions present in some species of snakes is to cause death or the rapid immobilization of prey to facilitate its capture, as well as to aid in the process of digestion. If the venom is injected into humans, however, it may lead to a series of traumatic events, which, depending on the quantity of venom injected, the site of the bite, the size and physical stature of the person, and the particular species of snake, without special help or treatment the venom may cause anywhere from temporary or mild reactions to physical or permanent damage, or even death. The glands producing the venom are located in the snake's head, just behind the eyes.
Venom is a clear or yellowish substance composed of a complex mixture of proteins, enzymes and other chemical elements, and it varies in accordance to the species and taxonomic group. For a detailed review of venom and antivenoms, I recommend Bolaños & Cerdas (1980), Bolaños (1984), Gutiérrez et al. (1999), and Rojas et al. (2001).
Serum or Antivenom
The only laboratory in Central America to specialize in the production of serum for snakebite is located in Costa Rica . The Instituto Clodomiro Picado at the University of Costa Rica [telephones (506) 229-0344, 229-3135; fax (506) 292-0485; http.//www.ucr.ac.cr/~icpucr], founded in 1970, produces and distributes the antivenom ANTICORAL, which is specific for the venom of coralsnakes (Family Elapidae), and the antivenom POLIVALENTE, which acts on the venom of pitvipers of the family Viperidae (Gutiérrez & Rojas 1999, Gutiérrez et al. 1999, and Rojas et al 2001).
First Aid and the Use of Antivenom
In case of snakebite, remember:
- REMAIN CALM, there is enough time to treat this type of an accident. In general, snakebite causes some degree of commotion or fear, and there is a tendency to believe that a person can die within a few minutes. This is NOT TRUE, and for this reason one should remain calm and transfer the victim to a medical facility.
- Try to prevent the person from becoming AGITATED, and do everything possible to immobilize the extremity or affected area.
- DO NOT provide any type of alcoholic beverage or medication.
- DO NOT use a tourniquet OR make cuts or incisions at the site of the bite, and DO NOT attempt to use your mouth to suck out the venom. This will eliminate the risk of anoxia, severe hemorrhage, or infection.
- If it is available and you know how to use it, a syringe with a suction cup called the “venom extractor may be used within 10 minutes after a bite. Remember that the use of this apparatus is NOT A SUBSTITUTE for medical attention, which the victim needs to receive as soon as possible. Also, be aware that the efficiency of the venom extractor has been questioned in various medical studies that have considered it incapable of extracting a significant amount of venom.
- To ensure adequate treatment, transfer the victim to a hospital or medical center as soon as possible.
- If the nearest hospital or medical center is less than four hours away, the use of serum is not recommended. It is preferable for a doctor to administer the serum at a facility.
- Serum should ONLY be administered when the symptoms of envenomation are evident.
- BEFORE injecting the serum, an allergic or hypersensitivity test must be performed. Remember that antivenom is a foreign substance to the human body, and is some cases it will trigger a severe and dangerous adverse reaction. The test should be performed SUBCUTANEOUSLY (under the skin) in the forearm by injecting 0.1 ml of the serum diluted in sterile saline at a 1:10 ratio, or at a ratio of 1:100 if the victim has a history of hypersensitivity. Allow 30 minutes for a reaction, which is evident by a hive-like swelling. Within 15 minutes, however, there may be itching, reddening of the area, and tearing. This test can provoke a severe allergic reaction, including the general symptoms of anaphylaxis, for which ADRENALINE at a ration of 1:1000 is recommended to counteract the anaphylactic shock. The amount of adrenaline used is measured according the victim's body weight, as well as by the severity of the allergic reaction.
- If a positive reaction is produced in either test, DO NOT administer the serum. It should only be administered at a hospital or medical center.
- If the reaction is negative, proceed to inject the serum INTRAMUSCULARLY (in the buttocks); it should NEVER be injected intravenously (this should only be performed by a doctor or a specialist at a hospital or medical center).
- Injection of four ampules of the anticoral or polyvalent serum are recommended, and the victim should immediately be transported to a hospital or medical center.
Snakebite in Costa Rica
Each year, about 500-800 people are bitten by venomous snakes in Costa Rica , and generally, from five to 10 people die. In most cases, fatalities occur because o a lack of medical treatment with anitvenom. Over 95% of the bites from venomous species are caused by members of the family Viperadae (pitvipers), and a minimal number are attributed to members of the family Elapidae (coralsnakes). Among the venomous species, the Terciopelo (Bothrops asper) ranks as the main protagonist, since it is undoubtedly responsible for the majority of bites not only in Costa Rica but throughout Central America . From a biomedical perspective, its large size, quantity and potency of its venom, and its relative abundance (due to a high reproductive potential and ability to adapt to altered habitats) makes this the most important species. This snake deserves the utmost respect and caution from anyone traversing its habitat.
Agricultural workers in rural areas receive the most bites from venomous snakes, but no one is exempt from this type of an accident unless basic precautions are taken when traversing areas where these snakes are found.
To Prevent the Risk of Snakebite, Remember:
- Avoid walking barefoot in forested areas, and always use high rubber or leather boots.
- Avoid areas where you can not clearly see the forest floor.
- Do not use your hands or feet to inspect holes, lift rocks, logs, or forest undergrowth; instead, use a rod, machete, or a large branch.
- If you walk at night, ALWAYS use a flashlight or a lantern so you can see clearly, and remember that many snakes are active after dark.
- If you find a snake, maintain a proper distance and avoid making any sudden movements. Remember that snakes are incapable of chasing or biting you unless you molest, injure, or attempt to capture them.
If you are not an experienced snake handler, do not attempt to capture them; it is better to carefully observe snakes and avoid an accident.
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