Snake bites

Snake-bite is an occupational disease of farmers, plantation workers, herdsmen, fishermen, snake restaurant workers, and other food producers. It is, therefore, a medical problem that has important implications for the nutrition and economy of the countries where it occurs commonly. It is recommended that snake-bite should be formally recognized as an important occupational disease in the South East Asian region.

Snakebite envenoming is a potentially life-threatening disease that typically results from the injection of a mixture of different toxins (“venom”) following the bite of a venomous snake. Envenoming can also be caused by having venom sprayed into the eyes by certain species of snakes that have the ability to spit venom as a defence measure.

Fundamentally, Envenoming results from snake bites is a particularly important public health problem in rural areas of tropical and subtropical countries situated in Africa, Asia, Oceania, and Latin America.

The major groups of snakes causing envenoming are the elapids (cobras, kraits, mambas, etc.) and vipers, and in some regions, sea snakes. Snake venom is a complex mixture of many different compounds. The composition and effects of venom vary considerably between species to species, but can broadly be divided into categories which include i) cytotoxins causing local swelling and tissue damage, ii) haemorrhages which disturb the integrity of blood vessels, iii) compounds which lead to in-coagulable blood, iv) neurotoxins causing in neurotoxicity and iv) mycotoxins which cause muscle breakdown.

Victims of snake-bite may suffer any or all of the following:

(1) Local envenoming confined to the part of the body that has been bitten. These effects may be debilitating, sometimes permanently.

(2) Systemic envenoming involving organs and tissues away from the part of the body that has been bitten. These effects may be life-threatening and debilitating, sometimes permanently.

(3) Effects of anxiety prompted by the frightening experience of being bitten and by exaggerated beliefs about the potency and speed of action of snake venoms. These symptoms can be misleading for medical personnel.

(4) Effects of first-aid and other pre-hospital treatments that may cause misleading clinical features.

These may be debilitating and rarely even life-threatening. (3) And (4) may develop in patients who are envenomed and in those who are not envenomed (bite by a non-venomous snake or by a venomous snake that failed to inject venom) or who were not in fact bitten by a snake at all but by a rodent or lizard or even impaled by a thorn.

Antivenom treatment for snake-bite was first introduced by Albert Calmette at the Institute Pasteur in Saigon in the 1890s (Bon and Goyffon 1996). Antivenom is immunoglobulin [usually pepsin-refined F(ab’)2 fragment of the whole IgG] purified from the plasma of a horse, mule, or donkey (equine) or sheep (ovine) that has been immunized with the venoms of one or more species of snake. “Specific” antivenom, implies that the antivenom has been raised against the venom of the snake that has bitten the patient and that it can therefore be expected to contain a specific antibody that will neutralize that particular venom and perhaps the venoms of closely related species (para specific neutralization). Monovalent (mono-specific) antivenom neutralizes the venom of only one species of snake. Polyvalent (poly-specific) antivenom neutralizes the venoms of several different species of snakes, usually the most important species, from a medical point of view, in a particular geographical area.

  • No alternative successful therapy
  • A high degree of mortality and morbidity in the absence of treatment
  • The diseases in which they are used represent a heavy toll of human suffering
  • Largely affects children and farmers in rural communities
  • Unfortunately, there are a number of problems for developing countries in accessing and using antivenoms – W.H.O.

Principles of first-aid First-aid treatment is carried out immediately or very soon after the bite before the patient reaches a dispensary or hospital. It can be performed by the snake-bite victim himself/herself or by anyone else who is present and able. Unfortunately, most of the traditional, popular, available, and affordable first-aid methods have proved to be useless or even frankly dangerous. These methods include: making local incisions or pricks/punctures (“tattooing”) at the site of the bite or in the bitten limb, attempts to suck the venom out of the wound, use of (black) snake stones, tying tight bands (tourniquets) around the limb, electric shock, topical instillation or application of chemicals, herbs or ice packs. Must not be allowed to delay medical treatment or to do harm.