© Alexandra Malm/MSF

Snakebite

Almost three million people are bitten by venomous snakes every year. However, life-saving treatment is expensive or hard to access.

Snakebite is a hidden health crisis that kills more than 100,000 people a year.

Although the exact number of global snakebites is unknown, estimates put the number of people bitten by venomous species at 2.7 million a year.

Of these, more than 400,000 will require an amputation or be left with a permanent disability. In sub-Saharan Africa alone, more than 20,000 people will die from snakebites each year.

MSF is campaigning to improve access to more effective and affordable antivenom – a major barrier to improving survival rates. 

What causes snakebite?

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Most people bitten by snakes live in tropical or subtropical countries where venomous species are endemic. Those most at risk include farmers or communities living in rural areas.

The highest number of cases seen by MSF are in Central African Republic, South Sudan, Ethiopia and Yemen.

However, in many affected counties, access to appropriate medical care can be restricted by:

  • A lack of effective or affordable antivenom
  • Limited training for medical staff
  • An absence of ambulance services to rapidly transport patients to hospital
  • Distrust in antivenom due to low-quality products on the market

For these reasons, in 2017 the World Health Organisation (WHO) classified snakebite as a neglected tropical disease.

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Symptoms of snakebite

The venom from a snakebite is often unique to the species of snake involved. However, three main conditions generally result from the different venoms:

Cytotoxic venom attacks the body’s cells.

  • This causes rapid and painful swelling that can progress into necrosis, meaning tissue around the bite can die off irreversibly. Entire limbs can be affected and it is particularly dangerous when a patient’s airway swells.

Haemotoxic venom causes bleeding that fails to clot.

  • This means prolonged bleeding from the bite itself, as well as other wounds or the gums and mouth. In more serious cases, patients can experience spontaneous bleeding, shock and convulsions.

Neurotoxic venom affects the central nervous system.

  • This can cause numbness, excessive sweating, salivation and a strange taste in the mouth, followed by droopy eyelids and problems speaking. In severe cases, patients may experience lockjaw, breathing difficulties and eventual paralysis – leading to respiratory failure as the muscles responsible for breathing stop working.

Venoms can also cause low blood pressure, increased heart rate, upper-back pain, vomiting and diarrhoea.

A group from a village in Central African Republic are shown a highly-dangerous Green Mamba snake.

Diagnosing snakebite

The initial sign of a snakebite is a bite, often to the arms or legs, with two distinct puncture wounds from the animal’s fangs.

Ideally, medical staff should quickly determine the species of snake involved. This will decide the type of treatment required.

However, identifying the exact species can often be difficult.

Treating snakebite

The use of antivenom – an antidote to snake venom – is the most reliable treatment for snakebite. In some cases, it is the only way to prevent death.

In 2017, MSF treated 3,000 patients for snakebite. Half of these required and received treatment with antivenom.

Eighteen-year-old Banywich had to have his leg amputated after he was bitten by a snake in South Sudan.

However, limited access to quality antivenom is still the biggest obstacle to survival:

  • In remote, rural locations, medical care may be several hours away while stocks of antivenom can be non-existent.
  • In some regions, available medication is often ineffective or non-specific to common snakes in the region.
  • Low-quality antivenom can trigger life-threatening side effects such as anaphylaxis – an extreme allergic reaction.

In sub-Saharan Africa, only two percent of people bitten by venomous snakes were estimated to have access to quality antivenom in 2010.

For these reasons, MSF projects in affected areas carry stocks of high-quality antivenoms that are appropriate for the range of native species.

The high cost of antivenom is a major barrier to people accessing treatment.

Issues around snakebite antivenom create a vicious cycle

The expensive price for the required number of doses can drive entire families into debt, forcing patients to cut short their treatment. They may then try cheap but low-quality antivenom or visit untrained traditional healers – putting their health at further risk.

This results in a vicious circle: High-prices drive people to use low-quality antivenom, causing them to lose confidence in the medication altogether. This creates a drop in demand that means quality suppliers either raise their prices further or stop production altogether.

Last reviewed: 20 June 2018