The Treatment of Snake Envenomation in Southern Africa

Dr. John Pridgeon

Having been a keen amateur herpetologist, since before I could spell the word snake, the treatment of that potentially fatal mishap called “a snake bite” has always loomed large in my mind, and in my imagination. Hopefully you will find this article useful, and I pray it will save lives if you are unfortunate enough to be present when Mr Nyoka strikes, and remember to do what is written below.

Although my wife will not agree, I am extremely respectful of these creatures. They are in fact wondrous animals, and without them we would be in terrible trouble: I am sure that very few of you reading this understand where snakes it in the food chain, or how important they are for the natural balance of fauna populations generally. Recently some misguide idiots decided to get rid of the African Rock Pythons living on our Phakalane Golf Course, situated near where I live in Gaborone, and the resultant rodent crisis helped those cretins understand that, for a virtually non-existent threat to humans, Phakalane golfers enjoyed an effective and effortless vermin control and an interesting round of dammit if they happened to see any. Until they relocated those snakes.

My snake exposures, like most people addicted to the African bush, have been many and varied, and so far, so good, I have lived to tell this tale. As a youngster I left no stone unturned, and we had a really nice little snake park at home, not nearly as jaw dropping as the one behind the Eskimo Hut in Bulawayo. The threat of snakes is totally overstated, and maybe the result of a Garden of Eden hangover! In the course of my 36 years as a GP in snake ridden Botswana, my experience has been very limited, dismal I am thankful to report. I have managed only 3 human bites, all per kind favour of the (never try to grab and hold this mother – ask Weasel!) Stilletto snake (also called the Wright’s Southern Burrowing Adder), half a dozen Mocambique Spitting Cobra envenomated eyes, and one canine Puff Adder bite.

I think if we knew how many snakes live in very close proximity to us, those who fear snakes would not even venture out of bed in the morning! And with this in mind, it is remarkable how few people are actually bitten by snakes. Snakes are timid, fearful creatures, but, if you think about it, that is hardly surprising – one day try playing the “I’m a snake” game, by lying flat on the ground, and simultaneously imagining something approaching you, that is more than fifty times taller than you, and that weighs a hundred times your weight (like a 4king big elephant), and it is not very difficult to understand why, unless surprised or trapped, they always try very hard to make themselves small and / or scarce, in the event of them finding themselves in our close proximity. Adrenaline driven fright will cause them to confront us and strike, and all anyone ever has to do is to stop and remain perfectly still. Usually within seconds, their raised  and ready to strike heads will lower, and they will slither on their merry way without any further threatening gestures. The first Warden of Kruger National Park, Harry Wolhuter, describes in Memories of a Game Ranger, a few hairy black mamba stories, of people being chased on horseback, and one on a bicycle. I recall another Kruger incident where a hapless horse rider had a mamba literally drop onto him, totally unprovoked. Whether intentionally or by snake mistake, the lucky traveller got away unscathed. But a change of undies was necessary.

A little bit about these wondrous creatures: there are roughly 500 reptile species to be found south of the Zambesi / Cunene River systems. Of the 147 venomous snake species, 14 are potentially fatal and another 18 will have a bite that one could describe as inconvenient and uncomfortable! Snakes, lizards and worm lizards are all from the order Squamata. Mating occurs in spring in temperate climates, or at the start of the wet season in hotter areas. Most reptiles are oviparous, but only 2 brood their eggs, the Nile Crocodile and the Python. Some snakes are viviparous (none in southern Africa as these usually live in colder climes) giving birth to live young. Distinctive species-specific scale patterns must often be used for identification where snakes are similar, and anyone who knows  snakes will often be astounded at the colour differences that may occur within a species. Reptiles are poikilotherms / ectotherms, which means they must rely upon the sun for increasing body warmth. Snakes do not have eyelids, ergo any reptile with eyelids is NOT a snake, which is a useful diagnostic feature when you encounter legless lizards. Snakes instinctively track moving things, and tend to quickly lose interest in anything stationary. If possible, especially if you don’t know what it is, keep more than 2-3 meter distant from all snakes at all times. If you encounter one just stop, keep very still, and only interact with them thereafter if your circumstances force you to move. Unplanned bowel motions can be sorted out once the snake has left the scene!

There are 3 distinct types of snake venom: their effects distinguishable by the snake, or by the bite signs and  symptoms, if the snake was not seen or can’t be identified. Remember, some snakes like Gaboon Vipers, Rinkhals and Berg Adders have a mixed venom type, and therefore present a more complicated clinical picture … so reassess your patient every 15-20 minutes, and treat as the developing symptoms dictate.

• Neurotoxic – cobras and mambas – these snakes are quick, aggressive and should NEVER be messed with. Anyone who plays with mambas deserves to join those already on the “Darwin Award” lists.  Signs of serious envenomation include the development of strange sensations, difficulty with swallowing, double / blurred vision and progressive paralysis.

• Cytotoxic – adders and vipers – are also fast and furious, so keep your distance, but they are often well disguised ambush predators, and the first time you see or hear them might be when they are hanging by their front fangs from your leg! Pain is the overwhelming feature of these bites, with severe swelling, and blister formation to follow – the severe associated problems associated with tissue damage and cell death take time, but with the correct medical management sequelae these are usually minimal.

• Haematotoxic – boomslangs and the vine snake; these are very shy snakes usually, and serious bites occur almost exclusively among snake catchers; the fixed back fangs mean the snake must literally chew on the victim for a while for envenomation to occur! These snakes cause disseminated clotting, which takes hours, and once all of the clotting factors are exhausted, uncontrolled bleeding from eyes, mouth nose etc occurs – without clotting factor and platelet replacement, these people just literally bleed out in front of you.

The management of snake bites is complicated and should be left to those who know something about it. I am sure most readers will not know the first thing about treating severe allergic reaction caused by giving antivenin! So do NOT give that stuff unless you know what you are doing.

Here is an excellent review for the wannabeasnakefundis – Snake bite in southern Africa: diagnosis and management http://www.cmej.org.za/index.php/cmej/article/view/2546/2581

General First Aid:

Probably the best advice I could give in any snake bite situation is:

1. Species diagnosis is critically important, try to identify the beastie, but don’t waste too much time doing this. Snakes have right of way – allow them to escape; taking a pic to type the snake is an excellent idea, but fraught with danger, and trying to kill the thing is even more foolhardy for exactly the same reason – be careful not to become the second victim; dead snakes should be taken along to hospital, but be careful – even a scratch from a dead mamba fang can cause issues, and people have been bitten through the bag before now, so hokoyo! If the snake is still at large, do not risk further bites and carefully vacate the area.
2. Reassure the victim, who may be terrified, and keep them super quiet. Tranquillise with a benzodiazepine or antihistamine if available, but do not give alcohol as that facilitates the spread of the venom to heart, lungs and brain – never a good outcome!
3. If you suspect a neurotoxic cobra or mamba bite, especially if the patient is far from medical help, splint and immobilise the limb, and wrap in a firmly applied crepe bandage if available, starting proximal to the bite site, as this slows the proximal lymphatic spread of the venom. Remove constricting clothing, rings, bracelets, bands, shoes, etc, especially from the bitten limb / area.This procedure may reduce rapid distribution of the venom. Avoid crepe or other bandaging in all cytotoxic bites, as this will further compromise blood flow to the affected area, already struggling because the vicious swelling within the fibrous compartments created by the fibrous fascia that encases all muscles.
4. Go with unrisky haste to the nearest hospital ASAP, phone ahead if possible; on the way fill the victim with as much vitamin C as is available (liposomal is best, because it is 100% absorbed, and quickly) – remember you cannot overdose with this stuff, and side effects (diarrhoea) are unlikely as the body tends to improve its intestinal absorption in pathological situations such as envenomation and infection. I NEVER GO ANYWHERE without a sh*tload of C!
5. Two types of snakes are rapidly fatal – the Cape Cobra (the # 1 killer of South Africans), and the Black mamba – they both produce an uber potent neurotoxic venom, so bites are rapidly followed by neurotoxic symptoms – 20 to 30 minutes is all you have before the nervous system starts shutting down; while other types of bites can be serious, neurotoxic venom is the one that kills >90% of snake bite victims; mambas are particularly aggressive snakes (apparently their testosterone levels are through the roof!) and several records exist where more than one person was fatally bitten – I seem to recall an instance, in Mocambique or Zim I think, where all seven occupants of a rural mud hut were found dead – it is likely a black mamba was involved. Tragically, in Francistown last year, a youngster playing in a river bed died from a black mamba bite before they could get him to hospital. Paralytic respiratory failure is that fast.
6. Victims that stop breathing can be kept alive by mouth to mouth until they are intubated and ventilated at the hospital, so while a pulse is present you must never stop mouth to mouth, and by continuously monitoring the pulse manually you will be able to see how well you are breathing for the victim; death by asphyxia only occurs once the heart stops beating, because heart muscle requires oxygenated blood to contract.
7. Further treatment is complex, and will depend upon the snake’s type of venom, the effectiveness of your first aid, and how much venom was injected at the time of the bite.
8. Try always to identify the actual bite site, often seen as one or two oozing holes in the skin below the knee, but bites may be anywhere – bitten necks and faces are quickly followed by fast proximal envenomation, and obviously restrictive crepe bandages cannot be applied. But most people have a good idea of where they were bitten anyway, so these sites should be easily found. An amusing story of a drunk young gentleman being rushed to Hospital from a farm just outside of Harare comes to mind. The canny Casualty Officer held back on giving the highly toxic antivenin, as he could not identify the bite site. When the rescuing party later went back to the scene of the crime, they found a duck nesting in the out-house toilet – where the young man had been allegedly assaulted by the newly classified reptile – the pissedoffmommyducksnake! About 10% of bites are “dry bites” where the snake does not inject venom – it is also for this reason that the dangerous but lifesaving antivenin should be withheld, and only be given once signs and symptoms of envenomation develop.
9. As mentioned above, cardiopulmonary resuscitation (CPR) may be needed. This includes clearance of the airway, oxygen administration by face mask or nasal catheters, and establishment of intravenous access. If the patient is unresponsive and no respiratory movement is detectable, start CPR. Pulse oximeters are very handy. In case of respiratory distress / failure: clear the airway, lift the chin, give oxygen by face mask or nasal catheters with or without assisted ventilation and consider the need for endotracheal intubation. Shocked, hypotensive patients should be given intravenous fluids. Pressor agents, such as dopamine or phenylephrine may need to be administered.
10. Give analgesia by mouth if required: paracetamol (acetaminophen) or paracetamol / codeine combinations are preferred. Aspirin and other non-steroidal anti-inflammatory agents should be avoided in patients with haemostatic disorders. When using parenteral opioids in cyto- or neurotoxic snake bites, like morphine, respiratory function should always be monitored closely.
11. In cases where the snake has not been identified it is recommended that asymptomatic patients be routinely admitted to a medical facility for observations for 12 – 24 hours. Many hapless victims of late envenomation, that were prematurely given the all clear, have died at home or on their way back to casualty.
12. Avoid the many harmful and time-wasting traditional first-aid treatments such as cauterisation, local incision or excision, tattooing, immediate prophylactic amputation of the bitten digit, suction by mouth or vacuum pumps or ‘venom-ex’ apparatuses, instillation of chemical compounds such as potassium permanganate, application of petrol, ice packs, ‘snake stones’ and electric shocks. The above measures are contraindicated as they are potentially harmful, and none has any proven benefit. That said, Tiaan, a mamba bitten friend of mine in Francistown bravely and immediately after being bitten, blew his finger off with a shot gun rather than face the potentially fatal consequences. I am unsure if I would have been able to make that decision.

Venom Management:

1. Classical – antivenin is given IV in a theatre type setting, with every emergency medication required to manage a fatal severe anaphylaxis type of reaction readily available, which may occur at any time during the administration of as many vials as is necessary (up to 20 vials!) to halt the progression of symptoms.
2. Vitamin C – best given IV or orally as liposomal C, but use anything to hand. The more the merrier. Unlike antivenin it has ZERO side effects except diarrhoea, and in bigger doses haemolysis may occur (One in 300 people has a genetic trait called G6PD. The most common genetic enzyme deficiency worldwide is Glucose-6-Phosphate Dehydrogenase (G6PD) deficiency. This condition affects the red blood cells, making them more vulnerable to oxidative stress. It is an X-linked hereditary disorder, meaning it is more prevalent in males and often passed down through maternal genes. G6PD deficiency can lead to symptoms like neonatal jaundice and acute haemolytic anaemia, especially when triggered by certain medications, infections, or foods (like fava beans). And IV vitamin C – more than the 25,000 mg is usually required to cause haemolysis.)

The SAIMR produces 2 antivenins, one polyvalent, used for neuro- and cytotoxic venoms, and the second monovalent, used only for boomslangs. Quite a few cobras and adders have mixed effects, neuro- and cytotoxic venoms, and bites are managed accordingly.

Johan Marais heads up the ASI (African Snake Bite Institute) and has done an extraordinary amount of brilliant work on snakes, to try to help the lay public understand them better. Well done Johan for your magnificent contribution to herpetology in Southern Africa! I strongly recommend his courses for anyone wanting to know more about snakes – for more details go to  https://www.africansnakebiteinstitute.com/online-courses/online-course-beginners-guide-to-snake-identification-southern-africa/lessons/shovel-snouts/

Sadly, the people at ASI seem to have a blind spot, and several times I have tried unsuccessfully by email to help them understand that antivenin is not the B all and end all for envenomation treatment, but they have repeatedly declined to accept the worth of ascorbic acid (= good old vitamin C) in the immediate treatment of serious envenomation.

They completely and inexplicably discard the cheap as chips, highly effective and often immediately available, SIDE EFFECT FREE ascorbic acid, in favour of antivenin. Dit gaan my verstand te bowe, as they say, behind the boerewors curtain!

Since the mid-nineteen forties an amazing American Respiratory Physician, Dr Fred Klenner, started working with high dose vitamin C, usually in the form of sodium ascorbate. He found that as a general antidote or treatment for infection its effects were near miraculous. His many experiences make excellent reading https://vitaminc.co.nz/pdf/CLINICAL-GUIDE-TO-THE-USE-OF-VITAMIN-C-FREDERICK-KLENNER-MD.pdf and the reader would be well advised that spending an hour reading about what a panacea for all ills your new bestie C can be.

Copied and pasted from this pdf is the following passage –

Snakebite: Klenner reported on a four-year-old girl bitten by a Highland Moccasin. She had severe pain in her leg and was vomiting within twenty minutes after the bite. Dr. Klenner gave four grams of C intravenously and within half an hour she had stopped crying and could now drink orangeade and began to laugh. “I’m all right now.” She slept well all night, but because of a slight fever and tenderness, Dr. Klenner gave her another four grams intravenously and again that late afternoon. No antibiotics and no anti-serum were necessary. “Sodium ascorbate will cure any type of snake bite.” A similar bite incident occurred with the same snake species, and without C, that victim spent months recovering, and had to endure many surgeries to keep her leg!

Vitamin C is one of the most potent and effective antitoxins around. The amounts and the speed of injection are critical … 40 to 60 GRAMS intravenously as a starter. Heaven knows how many deaths occur from snake bites (India alone experiences a significant number of snakebite deaths annually, with estimates ranging from 45,900 to 58,000 deaths per year), and many occur more from insects, bees, spider, plants and some caterpillars. They produce formic acid, histamine and specific toxin albumins. Some are neurotoxins; some cause capillary damage and haemorrhage. When cells are damaged proteins are deaminized, producing histamine and other toxic products; shock may occur.

These deaminising enzymes from the damaged cells are inhibited by Vitamin C. The pH of cells changes when cells are damaged; enzymes become destructive instead of constructive. C reverses this. Any pre-existing, and often inadequate, vitamin C is automatically reduced in the serum of those in shock. 350-700 mg per kg body weight is the saving intravenous dose (give a 100 Kg man 70,000 mg!).

Some enlightened vets use ascorbic acid / ascorbate with good results, this because very few are willing to spend R40k on antivenin for their pooch! I attach the following interesting snippets for your interest, showing excellent results in animal trials

1. https://medcraveonline.com/MOJT/MOJT-02-00026.pdf . Their conclusion: We therefore show that Vipers venom causes tissue damage by increasing free radical mediated damage and that this can be controlled by the administration of antioxidants. This is of profound importance since the first line of intervention that is available in cases of snake bites is anti-venom therapy which itself is harmful to the body. We therefore propose the use of antioxidants along with antivenom therapy for enhanced clinical care

• https://www.jennypearce.com.au/wp-content/uploads/2017/10/vitcsnake.pdf

I believe that to continue to ignore this effective, cheap and readily available snake bite remedy to be something between stubborn folly, and being criminally liable for unnecessary injury and loss of life, when this should be explored better than it has been previously by people at risk – so all of you snake guys, take note!

Snake bite antivenom, IF available (it must be kept refrigerated, and becomes cloudy and unusable after only a short lifespan post manufacture) is bliksem expensive (monovalent Boomslang antivenom costs R6,800.00 per vial, while polyvalent antivenom costs R2,130.00 per vial, and at up to 20 vials per treatment that’s not chump change!), and antivenin WILL in every case produce an allergic response (either immediately, or as a delayed reaction called serum sickness) in 100% of cases. People receiving this stuff once will almost certainly die if given it a second time, because of the inevitable severe anaphylactic reaction. This occurs because the first treatment has almost always fatally sensitised them to the medicine. Antivenin can ONLY be safely given in a theatre type scenario, with IV lines up, and emergency medicines at the ready.

Snakes should be respected and NOT feared, or simply killed for just being snakes! They are amazing creatures, and perform an irreplaceable function in every ecosystem they can be found in. Leave them alone, admire them even, and all will be well.

P.S. I still can’t work out how they move so effortlessly, I have seen mambas move through trees faster than any man can run!