Venomous Bites and Stings Course

Johan Marais from the African Snakebite Institute and Dr Gerbus Muller from the Poison Centre at Tygerberg Hospital presented this course at the Medical School of the University of Stellenbosch.

The programme:

08:30 – 19:00    Registration.
09:00 – 10:30    Identification of important venomous snakes including a live snake                                                 demonstration by Johan Marais.
10:30 – 11:00    Tea and refreshments.
11:00 – 12:30    Management principles and anti-venom by Johan Marais.
12:30 – 13:00    Management of scorpion and spider bites by Dr. Gerbus Muller.

Johan’s opening slide with his contact information

Dispelling the snake and snake bite myths:
Johan ran us through the dangerous snakes in Southern Africa.  In the process he also dispelled myths and Old Wives’ Tales left right and centre and I list just a few of the casualties here.

Johan dispensing information and dispelling myths

Myth:   The Mole Snake (Pseudaspis cana) is non-venomous, therefore harmless and can be               handled by anyone with impunity.
Fact:    A Mole Snake has numerous short, sharp teeth and, when it bites, it moves its jaws                    back and forth in a sawing action.  The lacerations a large Mole Snake creates will                      require stitching and treatment with antibiotics.

Myth:    The Boomslang (Dispholidus typus) can only bite you on a finger or the edge of your                   hand because it has a small mouth and its fangs are at the back of the mouth.
Fact:     The Boomslang can open its mouth more than 170 degrees, which is quite wide                         enough to bite you anywhere it likes. Its teeth are also not at the back of its mouth but                 somewhere in the middle; roughly under the eye.

Myth:     The Puff adder (Bitis arietans) causes most of the serious bites in Southern Africa.
Fact:     That dubious distinction belongs to the Mozambique Spitting Cobra (Naja                                   mossambica).

Damage resulting from a bit by a Mozambique Spitting Cobra.
This is one of Johan’s slides which I photographed. All rights to the photo reside with Johan and the African Snake Bite Institute

Myth:     You can pick up any snake, as long as you know what you’re doing, by gripping it firmly               just behind the head.
Fact:     The Stiletto Snake (Atractaspis bibroni) can rotate its fangs in any direction and, in so                doing, stab you in a finger, no matter how you hold it.

Myth:     A Black Mamba (Dendroaspis polylepis) will chase you to bite you.
Fact:     All snakes become aggressive if cornered or threatened, but no snake in the world                     will chase you.

Myth:     Black Mambas have been known to strike at passing vehicles leaving deep fang                         marks in the metal.
Fact:      A Black Mamba’s fangs are so fragile one can break them with the flick of a finger.

Myth:      An adult Black Mamba can raise more than three-quarters of its body off the ground to                strike.
Fact:      A close examination of the Mamba’s anatomy shows that this feat is anatomically                       impossible for the snake.

Myth:     The Green Mamba (Dendroaspis angusticeps) hangs from tree branches striking at                    passers-by below
Fact:      Absolute rubbish.

Myth:      To keep snakes away from your house or campsite, purchase a can of snake                              repellent or Jay’s Fluid and spray the area.
Fact:      Not a single one of these repellents has been proven to have any deterrent effect on                    snakes.

Myth:      Electrotherapy is an effective treatment for snake bites.
Fact:      These instruments do not have any beneficial or curative effect on any snake bite.

Myth:      Snake stones and traditional herbal concoctions provide protection, not only against                  being bitten but also against the effects of the venom should you get bitten.
Fact:      Neither the stones or the many herbal concoctions have the slightest effect                                    whatsoever.

Important characteristics of snake bites and snake venom
All sorts of other interesting snippets of information about snakes also materialized.  Snakes apparently do not always deliver the same amount of venom when biting.  Many bites are “dry bites” in which no or very little venom is delivered.  Unfortunately one does not know this at the moment of the bite and the only way to be sure, is to wait and see if any symptoms develop. The risk here is obvious, so my advice would be to head for a medical facility and do your wait-and-see-thing on the way there.

The venom from the same species of snake, but from two different geographic locations can have different levels of toxicity.  This seems to be the case with the Cape Cobra (Naja nivea), which appears to be less venomous in the Northern Cape and Southern Namibia than in the Western and Southern Cape.

People also have different levels of allergic reaction to snake venom, which means that the effects of a snake bite can vary considerably from person to person.  Different people also vary in the degree of reaction to the anti-venom’s equine component, which further complicates treatment regimens.  This underlines the necessity for careful, post-bite monitoring by qualified medical personnel.

What to do and not to do when rendering snake bite first aid
Johan stressed that the administration of anti-venom should be left to suitably qualified, medical personnel.  The purpose of first aid was to stabilize the bite victim while getting them to a medical facility where medical personnel could take over. The golden rule when treating a snake bite victim is to always treat the symptoms and not the bite.

What to do.
Do get the victim to a medical facility as fast as possible.
Do keep the victim calm.
Do immobilize the bite area.
Do elevate the bite area to level with, or slightly above the level of the victim’s heart.  Please note that elevate does not mean lifting the bite area as high as possible above the patient’s head.

What to do, but only with discretion.
Only use a bag valve mask if you are properly trained in its use.
Only apply a crepe bandage if you are absolutely certain that the venom does not have any cytotoxic characteristics.

What not to do.
Do not cut or incise the bite.
Do not apply suction.
Do not apply a tourniquet.
Do not apply anything to the bite area or give the bite victim any medication.

The sort of damage that can result from improper & inappropriate use of a tourniquet.
This is one of Johan’s slides which I photographed. All rights to the photo reside with Johan and the African Snake Bite Institute.

The Live Snakes Session!
This gave us all the opportunity to become more closely acquainted with a number of live snakes.  First came a harmless American Milk Snake (Lampropeltis triangulum) and that was followed by a fair sized Mole Snake and a very dark, young Cape Cobra.  Next up was an older and larger Cape Cobra and then, the pièce de résistance, a beautiful Puff adder. Despite Johan’s assurances many of us made sure that we maintained a more than adequate distance, just in case.

Most people were quite happy and even eager to touch the Milk Snake.
Johan and a nice Mole Snake. My mobile phone’s camera was not quite up to freezing the motion of any of the snakes
Johan and the very dark (almost black) Cape Cobra
This was a large and very healthy Cape Cobra and I, for one, would not like to bump into it unexpectedly out in the veldt
What appears to be an almost too bright colouring in the Puff adder is actually perfect camouflage. When Johan put it on the floor the circle of onlookers widened just ever so slightly
This is how you safely handle a Puff adder. For some spectators the projection screen provided a safe refuge.
The braver spectators soon took the opportunity to touch the Puff adder.

Scorpions and spiders
Although Dr Muller’s time was rather limited, his talk was certainly no less interesting.  He identified Parabuthus granulatus as the most dangerous scorpion in this area and stressed that children were especially vulnerable with mortality rates running close to 20%.  A close second on the venomous list is Parabuthus transvaalicus, but it is only about a third as venomous as P. granulatus.  Both venoms are neurotoxic and the anti-venom, developed from P. transvaalicus, is effective for both bites.

Dr Gerdus Muller and in front of him is an large Erlenmeyer flask with preserved specimens of a large variety of preserved scorpions

Unlike snake venom, no allergic reactions to scorpion venom have been recorded but, in about 20% of the cases, there is an allergic reaction to the anti-venom.  The symptoms of scorpion venom develop very rapidly, often in less than two hours.  Deaths have been recorded within one and a half hours of the victim being stung.

This is one of Dr Muller’s very good slides illustrating how various types of neurotoxic venom work. It also explains the symptoms one observes in bite and sting victims.
This is one of Dr Muller’s slides which I photographed. All rights to the photo reside with Dr Muller and the Poison Centre at Tygerberg Hospital.
This chart gives a layout of the symptoms to be expected in scorpion sting victims.
This is one of Dr Muller’s slides which I photographed. All rights to the photo reside with Dr Muller and the Poison Centre at Tygerberg Hospital.

As far as spiders are concerned Gerbus reported that the main culprits responsible for envenomation were the Black Widow, (Latrodectus indistinctus) that has a neurotoxic venom and the Sac Spiders (Cheiracanthium sp) and Violin Spiders (Loxosceles sp.).  The latter two have cytotoxic venoms.  An effective anti-venom is available for the Black Widow spider.  The symptoms of bites by these two spiders and in particular the Black Widow, are referred to as Latrodectism. If you are looking for more information on spiders and guidelines on how to identify Norman Larsen answers questions on Iziko Museums of Cape Town’s Biodiversity Explorer page.

Two photographs of a positively identified Sac Spider bite. This particular patient only reported to the Poison Centre four or five days after the bite incident.
This is one of Dr Muller’s slides which I photographed. All rights to the photo reside with Dr Muller and the Poison Centre at Tygerberg Hospital.
This chart gives a layout of the symptoms to be expected in Latrodectism victims.
This is one of Dr Muller’s slides which I photographed. All rights to the photo reside with Dr Muller and the Poison Centre at Tygerberg Hospital.

Gerbus pointed out and important distinction between the South African Black Widow Spider and the spider with the same name in other parts of the world.  The South African spider does not have a red or orange hourglass mark on the underside of its abdomen, but in the rest of the world it does.  However, the South African Brown Widow Spider (Latrodectus geometricus) does have the orange hourglass marking.  It also has a neurotoxic venom that is only about 25% as toxic as that of the Black Widow.

It is important to remember that spiders do not run around looking for humans to bite.  They only bite when they are threatened, usually by means of applying pressure on them.  As spiders are small and generally secretive, people often apply pressure accidentally and then get bitten.

Dr Muller’s slide emphasizing the fact that not every necrotic skin lesion was the result of a spider’s bite.
This is one of Dr Muller’s slides which I photographed. All rights to the photo reside with Dr Muller and the Poison Centre at Tygerberg Hospital.

Dr. Muller emphasized that only a small percentage of patients, brought to the Poison Centre at Tygerberg Hospital with lesions, had actually been bitten by a spider.  There were many other possible causes of lesions very similar to those caused by cytoxic spider’s venom.