There are over 3000 species of snake, most of which are harmless to humans. A minority are venomous and around 250 of these are considered dangerous.
Most snakebites happen in tropical and sub tropical parts of Africa, the Americas, Asia, the Middle East and Oceania. People in poor agricultural areas are most affected with children, adolescents and young adults at particular risk.
Main Groups of Venomous Snake
Wide distribution, but absent from Australasia, Madagascar and some Pacific islands. Includes European vipers and rattlesnakes in the Americas. In Asia, Russell’s viper and the saw-scaled viper are among the most dangerous.
Mainly found in tropical and sub-tropical areas and includes many of the most dangerous species in the world e.g. cobras, kraits, mambas, coral snakes, sea snakes and all Australian venomous snakes.
Other venomous snakes that do not belong to these two groups are usually less dangerous.
Action of Venom
Snake venom acts in two main ways, affecting the nervous system or affecting the blood cells:
Effects of Snakebite
Early symptoms can include pain, throbbing and swelling spreading from the bite, although some highly venomous snakes have a relatively painless bite.
Later symptoms depend on snake species and can include:
- Non-specific: nausea, vomiting, faintness and/or dizziness, drowsiness, weakness.
- Swelling, blistering, bruising, bleeding, of skin and tissues.
- Vocal difficulties, paralysis of face and eyes, difficulty in swallowing, generalised paralysis, breathing problems.
- Shock and/or collapse, death.
General First Aid
- Move away from the place where the bite occurred as there may be more snakes.
- Immobilize the person bitten, reassure and advise to remain calm and still; agitation and movement encourage circulation of venom.
- If a sea snake bite has occurred, help the person out of the water if necessary. If the bite is on a limb, immobilize the limb, with a splint if possible.
- Remove rings, watches, bracelets, socks or any other constriction near the bite area as swelling is likely. Do not apply a tourniquet.
- Mark the area of the bite with a pen, if possible.
- If pain relief is needed, use only paracetamol.
- If possible, arrange to have the person transported to medical help.
- Remain with the person until help is available and monitor breathing. If necessary, place in the recovery position.
- Only if safe to do so, take a photograph of the snake as this may help with identification and therefore treatment options.
- Do not try to catch the snake. If the snake is still attached, safely remove it with a stick or another tool.
- Do not accept offers of “traditional” healing techniques.
- Do not make incisions around the bite and/or attempt to the suck out venom.
- Do not wash, rub, burn or cauterise the bite area.
- Do not apply hot or cold packs to the bite area.
- Do not give drinks rinks containing alcohol, caffeine, or any other stimulant.
- Do not apply pressure bandages unless advised by a medical professional to do so. The use of pressure bandages relies on correct identification of the snake.
Spitting Cobras and First Aid
Several species of cobra in Africa and South East Asia can spray venom over a distance of several metres. (Spitting cobras also deliver a highly venomous bite). The venom is often aimed at the eyes, resulting in severe pain, tissue damage and blindness.
- Irrigate the eye continuously using large volumes of water, ideally under a slow running tap. Hold the eyelids open and rotate the eyeball.
- In the absence of water other non-irritant liquids may be used, such as milk, beer or urine.
- The eye should be bandaged using a pad dressing and dark glasses worn until reaching medical help.
- Do not rub the eye.
Snakebite is a medical emergency that requires professional intervention as quickly as possible. Tell the doctor:
- Which part of their body was bitten.
- Where and where they were bitten.
- What kind of snake (if known), what it looked like (or show photo)
- Describe symptoms.
As antivenom is not used in every case of snake bite.
Prevention advice for travellers
Snakes are usually shy and unaggressive unless physically threatened. If a snake is encountered back away slowly and cautiously.
There is no simple rule for distinguishing a venomous snake from a non-venomous one. All snakes can bite and may inflict painful wounds even if non-venomous
- Avoid touching a snake even if it appears to be dead or non-venomous. This applies equally to snakes belonging to “snake charmers” or in snake restaurants or snake parks, particularly in Asian countries.
If travelling in an area where there are venomous snakes, make a note of where the nearest treatment centre is.
- Take care when walking in grassland or woodland. Be careful at night: use a torch. Snakes are hard to see and are more likely to bite if someone stands on them or gets too close.
- Wear boots and long trousers, gaiters may provide additional protection Do not go barefoot or wear sandals.
- Be careful around water – snakes may be attracted to rivers and pools.
- Avoid climbing on trees or rocks in areas where there may be snakes; avoid putting hands in crevices and holes
Farm buildings often attract snakes because of the presence of rodents. Snakes may enter houses to escape flooding during heavy rain and particular care should be taken at such times. If camping where there are snakes:
- Campsites should be kept free of leaves and other debris.
- Check any area where you intend to sit or sleep, every time.
- Use a hammock, or sleep under a mosquito net tucked in underneath the bed to keep snakes out.
- Collecting firewood can be risky – check carefully where you are putting your hands.
- Check bedding, clothing and shoes before use.
- Keep bags tightly closed and off the ground when not in use and check before putting hands inside.