Bites, snake (foreign)

Introduction
Symptoms
Causes
Diagnosis
Treatment
Prevention
Selected links
Useful Article?

Introduction

Snakes sometimes bite in self-defence if they are disturbed or provoked. Many different kinds of foreign (exotic) venomous snakes are kept in captivity in the UK and other European countries, sometimes illegally. Occasionally they bite their owners or others while being handled carelessly or when they escape from their cages.

Increasing numbers of UK residents also travel abroad to tropical countries, where there is a risk of being bitten by a foreign snake.

The only venomous snake that is found naturally in the wild in the UK is an adder. See the Health topic about Snake bites, adder for more information about this type of snake bite.

Some snakes are venomous and can inject venom (toxins produced by the snake) as they bite. A venomous snake may also bite without injecting any venom, called a ‘dry’ bite. A dry bite may cause:

pain where the snake fangs break the skin
anxiety

If a foreign snake injects venom through its bite it can cause more serious symptoms, including:

nausea (feeling sick)
vomiting
dizziness, fainting and shock
paralysis of the muscles

See Snake bites, foreign - symptoms for more information.

How common are foreign snake bites?

Each year, fewer than 10 UK residents are bitten by foreign snakes, either captive ones kept in the country or while they are travelling abroad.

More than 75 different species of exotic venomous snakes are held by private snake collectors in the UK, both legally and illegally. These snakes are thought to be responsible for a handful of snake bites in the UK each year. Most cases involve the snake's owner.

Worldwide, there are around five million snake bites every year.

Outlook

Foreign snake bites are more often serious than UK adder bites. A UK citizen died of a black mamba bite in Africa in 2006, but there has been no death from an exotic snake bite in the UK since the 19th century.

Worldwide, there are around 100,000 deaths from snake bites and 300,000 amputations or other permanent disabilities every year. Most of these occur in parts of the world where access to emergency medical services is limited or non-existent.

In the developed world, emergency treatment with anti-venom medicine is usually successful in treating bites by even the most venomous of snakes. See Snake bites, foreign - treatment for more information.

^^ Back to top

Symptoms

There are two different types of snake bite:

dry bites, where the snake releases no venom
venomous bites, where the snake releases venom

Symptoms of dry bites

The symptoms of a dry bite are usually limited to the part of the body that has been bitten. The symptoms include:

pain in the area of the bite caused by the snake’s fangs and teeth
anxiety

Dry bites should not require specialist medical treatment. However, if you are bitten by a snake you should still visit your local accident and emergency (A&E) department. This is because effects of the venom could appear later and require treatment.

Symptoms of venomous bites

The symptoms of a venomous snake bite include:

severe pain at the location of the bite
nausea (feeling sick)
vomiting
diarrhoea
dizziness, mental confusion, faintness, collapse and shock
bleeding from the mouth, nose and wounds
vomiting blood or passing blood in urine or stools
muscle paralysis, which can lead to breathing difficulties
irregular heartbeat and a fall in blood pressure

In the most severe cases, a venomous snake bite may cause:

paralysis, starting with drooping of the upper eyelids and progressing to an inability to breathe or move
shock and loss of consciousness
kidney failure with little or no urine being passed
massive blood loss, due to bleeding from the mouth, nose and wounds, vomiting blood and passing blood in urine or stools
death

Anaphylaxis

In a small number of people, venomous snake bites can trigger a severe allergic reaction, known as anaphylaxis or anaphylactic shock. This can occur immediately after a bite or several hours later.

Dial 999 to request an ambulance if you suspect that you or someone you know is experiencing anaphylaxis.

Symptoms of anaphylaxis include:

swollen face, lips, tongue and throat
swelling in the throat that can cause breathing difficulties
rapid heartbeat
itchy skin
a drop in blood pressure, causing shock

Shock is a life-threatening condition that occurs when there is an insufficient supply of oxygen to the body. Symptoms of shock include:

dizziness or mental confusion
faintness, loss of consciousness or collapsing
cold and clammy skin
blindness

Anaphylaxis should always be treated as a medical emergency, regardless of the severity of the reaction. Left untreated, the most serious cases of anaphylaxis can be life-threatening.

See the Health topic about Anaphylaxis for more information.

What should I do if I am bitten by a foreign snake?

If you are bitten by a foreign snake in the UK you should visit your nearest accident and emergency (A&E) department, even if your symptoms are only mild. Hospital staff will be able to check your bite for any signs of infection.

You can use the services directory to find your nearest A&E department.

If you are bitten by a snake while you are travelling abroad, you should go to the nearest hospital immediately for urgent medical treatment.

^^ Back to top

Causes

Snake venom contains toxins (poisons) that are designed to kill or immobilise the snake’s prey. There are four main types of snake venom toxins:

haemotoxins attack the circulatory system (heart and blood)
neurotoxins attack the nervous system where nerves connect to muscles
cytotoxins cause blood and plasma to leak into the tissues near the bite and eventually destroy the tissues around the bite
myotoxins destroy muscle tissue both at the site of the bite and generally throughout the body

Haemotoxins

Haemotoxins destroy red blood cells, which carry oxygen, and disrupt the blood's ability to clot. Other toxins can cause a drop in blood pressure, which can result in:

tissue and organ damage
loss of consciousness
death

Neurotoxins

Neurotoxins block or damage nerves where they connect to muscles, which prevents the nerve signals getting through. This causes paralysis and can result in symptoms such as:

muscle weakness throughout the body
swallowing and breathing difficulties, leading to the loss of normal lung function (respiratory failure) and death

Cytotoxins

Cytotoxins cause swelling, bruising, blistering and gangrene (death of tissue cells) near to the location of the snake bite. This may require plastic surgery or, in severe cases, amputation.

Myotoxins

Myotoxins can cause permanent damage by destroying your muscle cells, causing pain and muscle weakness. They may also damage your kidneys, which filter waste products from your blood, causing your urine to be very dark.

Reasons for snakes bite

Snakes bite and release venom for two reasons:

to immobilise or kill their prey
in self-defence

As humans are far too large for a venomous snake to eat, nearly all snake bites occur when somebody provokes a snake into acting in self-defence.

In many cases, provocation occurs by accident. For example, when a person accidentally steps on a snake while out walking. However, there are some cases where snake bites occur as a result of someone deliberately provoking a snake by:

kicking it
striking it
trying to pick it up

Many cases of snake bites that involve exotic snakes that are kept as pets occur when someone attempts to handle them or 'play' with them. This often takes place when the person has been drinking alcohol or using other recreational drugs.

Snakes around the world

Globally, there are more than 3,000 species of snake and around 600 of these are venomous (poisonous). Of these, the World Health Organization (WHO) considers over 200 to be ‘medically important’. This means that they are capable of causing:

severe illness
disability
death

Snake bites mainly affect agricultural workers and children. Children feel the effects of a bite more because they are smaller.

Venomous snakes mainly live in rural, tropical areas. Parts of the world where venomous snakes are widespread include:

Africa
Asia
Latin America

Among popular tourist destinations, snakes are also found in certain areas of:

America
Australia
Europe

The WHO database of venomous snakes allows you to search for regions of the world to see whether there are venomous snakes in the areas you are visiting.

^^ Back to top

Diagnosis

If you have been bitten by a snake, you should seek medical attention immediately (see Snake bites, foreign - treatment). The healthcare professionals who treat you may ask you about the colour and size of the snake to identify which type of snake has bitten you.

You may be admitted to hospital where the severity of the snake bite can be assessed by:

monitoring your symptoms, for example, any swelling or redness that appears
monitoring your general condition, for example, your heart rate and temperature
carrying out blood tests, to check the effects of venom on red and white blood cells, platelets and haemoglobin and on different systems of the body, such as your kidneys or muscles

In more serious snake bite cases, an electrocardiogram (ECG) may be used to monitor your heart function.

An ECG records the rhythms and electrical activity of your heart. Electrodes (small, sticky patches) are placed on your arms, legs and chest. The electrodes are connected to a machine that records the electrical signals of each heartbeat.

^^ Back to top

Treatment

There are many misconceptions about what to do immediately after a snake bite. If you or someone else has been bitten by a snake, you should follow the advice outlined below and seek immediate medical attention by visiting the nearest accident and emergency (A&E) department or dialling 999 to request an ambulance if it is a medical emergency.

Immediate action

If a snake bites you or someone else you should follow the advice listed below.

Remain calm and do not panic. Snake bites are rarely serious and very rarely fatal.
Try to remember the shape, size and colour of the snake. This is particularly important if you are in another country.
Keep the part of your body that has been bitten as still as possible because this will prevent the venom spreading around your body. You may want to secure the bitten body part with a sling (a supportive bandage) or a splint (a rigid support that helps keep the body part stable). However, do not make the sling or splint so tight that it restricts your blood flow.
Remove any jewellery and watches from the bitten limb because they could cut into your skin if the limb swells. However, do not attempt to remove any clothing, such as trousers.
Seek immediate medical attention (see below).

If you or someone else is bitten by a snake you should never:

Suck the venom out of the bite.
Rub anything into the wound.
Apply any tight bandage around the bitten limb to stop the spread of venom, such as a tourniquet or ligature. This does not help and can cause swelling, even if no venom has been released by the snake. It can damage the affected limb, even requiring amputation of the limb in extreme cases.
Try to catch or kill the snake.

Seeking medical attention

If an exotic snake bites you while you are in the UK, you should dial 999 for an ambulance.

If a snake bites you while you are travelling abroad, you should assume that it is a medical emergency and contact the relevant emergency medical services.

Hospital treatment

Even if you feel well after being bitten by a snake, you may be asked to stay in hospital for at least 24 hours. This is a precaution so that your blood pressure and general health can be monitored.

Anti-venom medications are antidotes to snake venom. Anti-venom may be required in bites involving exotic snakes where there is evidence that the venom has started to damage tissue near the bite and affect important bodily functions, such as your breathing or heartbeat.

Anti-venoms

Anti-venoms are produced by injecting a small, non-life-threatening amount of snake venom into a large animal, usually a horse. The animal's immune system produces antibodies. These are proteins that stick onto toxins and are capable of neutralising their effects. These antibodies are then taken from the animal, purified and stored in a refrigerator until they are needed.

In some people, anti-venoms can trigger a severe allergic reaction called anaphylaxis, so it is important that you are closely monitored after receiving your first dose. If you experience anaphylactic symptoms, such as an itchy rash, a fall in blood pressure or breathing difficulties, this can be treated with adrenaline. See the Health topic about Anaphylaxis - treatment for more information.

Because of the risk of anaphylaxis, anti-venoms should only ever be given by a qualified healthcare professional.

In some cases of a snake bite you may also need:

intravenous fluids (fluid given through a needle into a vein in your arm), if there has been a significant fall in blood pressure
blood transfusions, if you have lost a lot of blood

Recovery

During the recovery period, you may experience episodes of pain and swelling in the area of your body that has been bitten. These symptoms can usually be controlled by taking over-the-counter painkillers such as paracetamol. Always read the manufacturer’s instructions to make sure that:

the medication is suitable for you
you are taking the correct dose

Recovery times for snake bites can vary depending on the species involved.

Shock

Someone who has been bitten by a snake may go into shock. Shock is a life-threatening condition that occurs when there is an insufficient supply of oxygen to the body.

Shock should be treated as a medical emergency and you should immediately dial 999 to request an ambulance.

Symptoms of shock include:

faintness or collapsing
pale, cold, clammy skin
sweating
rapid, shallow breathing
weakness and dizziness
blindness
feeling sick and possibly vomiting

After calling for an ambulance, you should lie the person down (if their injuries allow it) and raise and support their legs. Use a coat or blanket to keep them warm. See First aid for shock for more information and advice.

Snake bites abroad

If you are travelling to an area where you may be at risk of snake bites, make sure you know how to contact the emergency medical services in that country.

If you are travelling abroad, you should also carry a first aid kit with you containing:

medications, such as painkillers and antacids (for indigestion)
rehydration sachets (for diarrhoea)
plasters, non-adherent dressings and bandages
insect repellent
sun cream

For more information, see the Fit For Travel website for a checklist of travel health considerations before you travel, such as vaccinations and travel insurance.

See Snake bites, foreign - prevention for more information about avoiding snake bites.

^^ Back to top

Prevention

If you are travelling in environments where venomous snakes are known to be widespread, such as a jungle or rainforest, you can avoid being bitten by following the advice below.

Wear boots and long trousers.
Never pick up a snake, even if you think it is harmless and even if it appears to be dead.
Never put your hand in a hole or crevice, for example, between rocks. If you need to retrieve a fallen object, stand well back and use a stick to reach it.
If you find yourself very close to a snake, stand completely still. Most snakes only strike at moving targets. If you remain calm and still, the snake will escape without harming you.
Remember that snakes are more active during warm weather and during the annual rainy season in tropical countries.
Do not sleep on the ground unless you are in a tent that has a sewn-in groundsheet. Use a hammock or raised bed.
Do not walk around barefoot in overgrown areas.

^^ Back to top