Snake venom is a highly complex substance, and its effects can vary greatly depending on the snake species—and sometimes even between individuals of the same species. All snake venoms are complex cocktails and when we say that Black Mamba venom is neurotoxic, it is predominantly neurotoxic.

To help us understand how venom works and what it does to the human body, experts usually group snake venom into three main categories based on its primary effects:

1. Neurotoxic Venom – Attacks the Nervous System

This type of venom affects how the brain communicates with the body. It can block nerve signals, leading to paralysis. Common symptoms of neurotoxic bites include:

• Drowsiness and confusion
• Blurred vision and drooping eyelids
• Difficulty speaking, swallowing, or breathing
• Muscle weakness
• In severe cases, paralysis of the muscles that control breathing

If left untreated, neurotoxic venom can lead to respiratory failure and death. Snakes in this category include:

• Black Mamba
• Green Mamba
• Cape Cobra
• Other non-spitting cobras

2. Cytotoxic Venom – Destroys Tissue

Cytotoxic venom damages cells and tissues near the bite site. This often causes intense pain, swelling, and tissue death (necrosis). Symptoms may include:

• Immediate burning pain
• Swelling that may spread over the entire limb
• Blistering and darkened skin
• In serious cases, muscle and skin tissue may die, possibly requiring surgical intervention

Snakes with mainly cytotoxic venom include:

• Puff Adder
• Mozambique Spitting Cobra
• Common Night Adder
• Bibron’s Stiletto Snake

3. Haemotoxic Venom – Affects Blood Clotting and Organs

Haemotoxic venom interferes with the body’s ability to clot blood, leading to internal and external bleeding. Symptoms may appear several hours after the bite and include:

• Oozing blood from the bite site
• Headache, nausea, and mental confusion
• Bleeding from the gums, nose, or small cuts
• Bruising under the skin
• Vomiting blood or bleeding from the bowels
• Potential kidney failure or brain haemorrhage

This type of venom is mainly found in:

• Boomslang
• Vine Snake

⚠️ Keep in mind: These categories are generalisations. Some snakes have venom that contains a mix of toxins. For example, the Forest Cobra has both neurotoxic and cytotoxic components. So, while we might say a snake has “neurotoxic venom,” it simply means that the most noticeable or dangerous effects are on the nervous system.

Antivenom: What It Is and How It Works

A Brief History of Antivenom

Antivenom (sometimes called antivenin) has saved countless lives since it was first used in 1886. In South Africa, the first local antivenom was developed in 1901 in Pietermaritzburg and came as part of a basic kit with a syringe, lancet (small blade), ligature (for tying above a bite), and two small bottles of serum.

By 1928, the South African Institute for Medical Research (SAIMR) began producing antivenom more systematically. Scientists tested different animals to produce the serum but eventually chose horses—they’re large enough to provide a high volume of blood without harm.

• Early antivenoms covered Cape Cobra and Puff Adder bites.
• In 1938, Gaboon Adder venom was added.
• By 1971, venoms from both southern African mambas and Jameson’s Mamba were included in what’s known as polyvalent antivenom—which provides neutralisation against the venom of multiple snake species.
• A monovalent antivenom (targets only one species) was developed in 1940 for the Boomslang.

Antivenom Today

South African Vaccine Producers (based in Johannesburg) manufacture:

• Monovalent antivenom for the Boomslang
• Polyvalent antivenom for snakes like the Puff Adder, Gaboon Adder, Rinkhals, Black and Green Mambas, and several dangerous cobras
• Monovalent antivenom for the Saw-scaled Viper (a snake not found in South Africa)

Production of antivenom at the SAVP has come to a standstill and, according to them, they are busy upgrading their facilities. This has led to major antivenom shortages over the past few years. We now have an alternative product called PanAf Premium, a polyvalent antivenom imported from India and it is stocked in both private and state hospitals as well as veterinary practises.

Important Facts About Antivenom

• Antivenom is not a first-aid treatment. It must be given in a hospital setting by a trained doctor and only when required.
• The dosage depends on the amount of venom, not the victim’s size or weight. A child will usually receive the same dose as an adult.
• Most patients receive 6 to 12 vials of polyvalent antivenom, or more if required, but it can vary.
• Up to 40% of patients may experience allergic reactions to the SAVP polyvalent antivenom whereas allergic reactions to Panaf Premium is rare. Some develop anaphylaxis, a severe and life-threatening reaction where blood pressure drops dangerously and the heart can stop. Doctors treat anaphylaxis with adrenaline.

In Summary

Understanding how different types of snake venom affect the body can help us respond more effectively to snakebite emergencies. It’s important to remember:

• Not all snakes inject venom when they bite (these are called “dry bites”).
• Many victims are bitten by harmless or mildly venomous snakes.
• Symptoms can vary widely depending on the species and the amount of venom injected.
• Antivenom can be lifesaving, but it must be used only when required and only in a hospital setting.

If you or someone else is bitten by a snake, seek emergency medical attention immediately—and try to identify the snake if it can be done safely. Time is critical, and the right treatment can make all the difference.