The only effective treatment for severe snakebite envenomation from a potentially deadly snake is antivenom. Using antivenom is not easy and it has its disadvantages, but in the right hands and at the right time, it may well be lifesaving. People often have a poor understanding of how it works, and there are endless myths about antivenom killing more people than the snake venom itself. Not to mention numerous ‘miracle’ cures including antihistamine, cortisone and Vitamin C, to name but a few. Antivenom is also not a first aid measure and lay people should never attempt to administer antivenom.
84% of all snakebites are below the knee.
Antivenom for snakebite was first used in South Africa back in 1886 and local production started in Pietermaritzburg in 1901, but in small quantities with most of the antivenom still being imported from the Pasteur Institute in Paris, France. In those days one could purchase a 10 ml vial of cobra or mamba antivenom from Mr. F.W. FitzSimons, Director of Port Elizabeth Museum.
A Vial of Antivenom.
In 1928 the South African Institute for Medical Research (SAIMR) started producing antivenom, which was initially limited to Cape Cobra and Puff Adder venom. Gaboon Adder venom was included into the manufacturing process in 1938. Around this time the first monovalent Boomslang antivenom was also developed.
Milking snakes for antivenom production.
Rinkhals venom was then added, followed by the production of different mamba antivenoms in the ‘50s and ‘60s, and in 1971 the venom of the Forest Cobra, Mozambique Spitting Cobra and Snouted Cobra was included to produce the polyvalent antivenom that is still manufactured today.
Antivenom is created using a variety of animals including sheep, donkeys and camels, but in South Africa we use horses. A horse is either hyperimmunized with a single snake venom (Boomslang antivenom) or against venoms of a variety of snake species (polyvalent antivenom). This is done over an extended period of time, during which a small quantity of venom is injected into an animal and the quantity is increased over time as the animal builds up an immunity.
Once immunized, plasma is collected from the horse and it then goes through a process to remove proteins, pyrogens and microbes. The Polyvalent antivenom is captured in 10 ml glass vials, which currently costs R 1,736.00 a vial and they expire after three years if properly refrigerated. Monovalent Boomslang antivenom costs R 6,800.00 per vial and also expires after three years.
Few snakebite victims are treated with antivenom (less than 15% of those hospitalised after a snakebite). In most snakebites, the symptoms do not justify the administration of antivenom. It is expensive and can have serious side-effects. The biggest danger is an acute allergic reaction (anaphylaxis) or serum sickness that can affect the immune system several days after treatment.
Snakebite victims are not automatically injected with antivenom, as most of them never experience symptoms severe enough to justify its use. The majority of snakes have control over their venom glands and are quite reluctant to waste their venom on humans. They very often give ‘dry’ bites which result in no symptoms of envenomation, or the snake might inject a little bit of venom that will cause discomfort or some mild symptoms but nothing serious. Such patients are usually hospitalised for a day, carefully monitored, and then discharged.
Antivenom should only be used in a hospital environment, and only if the symptoms presented justify the need. Patients will already be on a drip and the antivenom is administered intravenously, although intraosseous administration may be a consideration if veins prove difficult to find. Most doctors will start with an initial dosage of 6 – 10 vials and in one severe mamba bite, a victim received more than 30 vials. He recovered fully. As already mentioned, some snakebite victims have a rapid allergic reaction to antivenom and this happens in more than 40% of all cases where antivenom is used. Some of these victims go into anaphylactic shock which is a life-threatening medical condition and must be treated with adrenaline. This has to do with the fact that our antivenom is made from horse blood and the allergy is basically an allergy to horse proteins. Additional processes in the manufacturing and purification of the polyvalent antivenom could reduce the incidences of anaphylaxis.
Antivenom should only be used if there is a threat to life or limb, by a medical doctor and in a hospital environment. It is highly effective and the sooner it is administered, the better. In neurotoxic bites (mambas and some cobras) the venom may soon affect breathing and these are the dangerous bites that often result in snakebite fatalities, whereas cytotoxic bites (Puff Adder and spitting cobras) usually result in swelling, blistering and tissue damage. The sooner the antivenom is administered, the better the chances of preventing necrosis or reducing the extent thereof. It is a popular myth that more people die from the antivenom than from the snake venom itself – this is not true at all – anaphylaxis is manageable if dealt with urgently and in the right manner.
Characteristic cytotoxic bite with severe swelling and blistering that often leads to tissue damage and necrosis.
Snake Gaiters
Meet the newest addition to our extensive range of snake gaiters.
Our new ASI Cordura Snake Gaiters come in both camo and green, and with either Velcro strips or buckles to fasten them.
Price: R625.00
Antivenom and Pregnancy
If a pregnant woman is bitten by a potentially deadly snake, can she be treated with antivenom and will it affect the foetus? I discussed this with Dr Gerbus Muller of the Tygerberg Poison Centre and Dr Colin Tilbury, both experienced snakebite doctors with many years of experience. In any serious snakebite, antivenom is administered to save life or limb. Other than the known side-effects of antivenom, it has no adverse effect on a healthy foetus. Withholding antivenom in such an emergency could lead to loss of life for both mother and the foetus.
Antivenom and Pets
Cats rarely get bitten, but dogs just cannot help themselves when they see a snake and invariably try to kill it. While some dogs are quite efficient at killing snakes, they usually end up getting bitten. In such an instance the dog must be taken to a vet immediately – there is no effective first aid. Giving a pet Allergex tablets, milk, charcoal, raw eggs, or any other medication does not help at all.
Most dogs, after a bite, receive 2 – 4 vials of polyvalent antivenom and seem to recover well provided the antivenom is given sooner rather than later. Such a treatment could cost anything from R4,000.00 – R20,000.00.
Dogs are often bitten by snakes as they attack the snakes. Photo Beryl Wilson
The new ASI Universal Field Hook is now in stock!
Made from industrial aluminium and tested to lift up to 4 kg.This versatile three-piece snake hook measures 40 cm when completely disassembled and 1.2 m when fully assembled. It can also be assembled as a two-piece, which measures 80 cm. It comes in it's own tie-up sleeve.
The prefect hook to take with on travels.
Price R495.00
Antivenom in Remote Areas
If you are in a remote area far from a medical center, should you purchase and keep antivenom? Antivenom is expensive and if you are going to purchase polyvalent antivenom for snakebite emergencies, purchase 15 vials (@ R1,736.00 per vial) and keep it in the fridge (not freezer) at all times. Never administer the antivenom yourself – take the snakebite victim and the antivenom to the nearest medical facility that has a trauma unit.
Why is there no antivenom for certain snake species?
The development of antivenom is an expensive and prolonged process that could take many years and cost millions of Rands. Once developed, the new antivenom must be clinically tested before it can be registered as a drug in South Africa. For that reason we do not have antivenom for a number of our snakes that can inflict serious bites but have not accounted for fatalities in South Africa. This includes Vine Snakes (Thelotornis sp.), the Berg Adder (Bitis atropos), Rhombic Night Adder (Causus rhombeatus) and Bibron’s Stiletto Snake (Atractaspis bibronii). Victims bitten by any of these snakes may require hospitalisation.
Polyvalent antivenom, Monovalent Boomslang antivenom, spider antivenom and scorpion antivenom are all manufactured and sold by the South African Vaccine Producers (SAVP). For details go to www.savp.co.za.
For advice on first aid treatment of snakebite, please have a look at the appropriate section on the ASI Snakes App.
African Snakebite Institute Herpetological Association
We'll be hosting the first public ASI Herpetological Association meeting on the 30th of October at Cradle Moon Lakeside Game Lodge in Mulderdrift.
Our guest speaker will be Dr Robert Campbell and he'll be discussing great husbandry in reptiles by approaching it from one Health.
Bookings are essential and can be done directly via our website here: https://bit.ly/3nYFLCU or email Bianca on fin@asiorg.co.za
Are you interested in learning more about snakes?
But can't make it to one of our popular public courses.
Don't stress, we have just the thing for you - you can now access our Snake Awareness and First Aid for Snakebite course online!
This comprehensive 6 module course covers scorpions, spiders and snakes of Southern Africa.
Snake anatomy, behavior, size and myths. Antivenom and snakebite prevention as well as first aid for snakebite.
Johan Marais is the author of various books on reptiles including the best-seller A Complete Guide to Snakes of Southern Africa. He is a popular public speaker and offers a variety of courses including Snake Awareness, Scorpion Awareness and Venomous Snake Handling. Johan is accredited by the International Society of Zoological Sciences (ISZS) and is a FGASA (Field Guides Association of Southern Africa) and SASTM (South African Society of Travel Medicine)-approved service provider. His courses are also accredited by the HPCSA (Health Professions Council of South Africa). Johan is a qualified instructor for the Emergency Care & Safety Institute in Oxygen Administration and Wilderness First Aid and a qualified Basic Life Support instructor.
