Of the 173-odd different types of snakes in southern Africa, the vast majority are either harmless or mildly venomous. Johan Marais writes about the possible effects of “mild” venom
While the venom of most mildly venomous snakes, such as the herald snake, the eastern tiger snake, various sand and grass snakes and the skaapsteker, have virtually no effect on humans, 29 snakes that are not considered deadly have rather potent venom that can cause a great deal of discomfort or even require hospital treatment. Unfortunately, many of these snakes are listed as “mildly venomous” on various internet sites. This is certainly not always the case.
The common or rhombic night adder is a good example. It is abundant in the wetter, eastern parts of the country and is a frog specialist, feeding largely on toads. Gardens with water features lure frogs, and the night adder follows.
The night adder’s venom is often described as mildly cytotoxic, which will cause some pain and a bit of swelling. This may be the case in some bites, but not always.
We see some particularly bad bites, especially on children and dogs. Night adder venom is potent enough to kill small dogs and I recently encountered a case where a Maltese poodle was bitten on a paw, and the front leg had to be amputated the next day.
In some areas, such as the Eastern Cape, night adder bites are common and children may end up with severe swelling and in rare cases, tissue damage. There is no anti-venom for this bite and doctors can only treat symptoms with pain killers.
Little can be done for the swelling. Swelling on an arm or leg can be severe enough to cause compartment syndrome – a condition where oxygenated blood does not reach the hand of foot. Though seldom required, this may necessitate a fasciotomy – a medical procedure in which the arm or leg is cut open longitudinally to relieve pressure on the veins.
The stiletto snake, previously called the burrowing adder, is responsible for a high number of painful snakebites. It is most active at night after summer rains, and most victims are bitten when they accidentally stand on one.
Because of its rather strange, hinged fangs that can protrude from the mouth independently, snake handlers are at risk because the stiletto cannot be held safely behind the head. The snake will extend one fang and turn its head sideways to inflict a bite — with painful results.
The venom is potently cytotoxic, causing tissue damage and in many cases results in the loss of a finger. To date we have not had any fatal bites in SA, but there have been deaths from stiletto snakes elsewhere in Africa. There is no anti-venom for this snake and treatment could take a few days or even weeks. Most stiletto snakes are 30cm-40cm in length, but may exceed 75cm. A bite from a large stiletto could be fatal.
Bites from the berg adder have been very serious and there have been cases where victims have spent weeks on a ventilator, or have lost their vision for months. Berg adder venom is a strange mixture of cytotoxins and neurotoxins, and the polyvalent anti-venom does not work against it.
Some popular books refer to fatalities, but there are no well documented cases. Having said that, a fatal bite from a large berg adder is a possibility. It is an ill-tempered snake that often basks on footpaths or on rocky ledges in mountainous areas. If you step close enough or accidentally place a hand close to a basking berg adder, it may just strike out.
Other lesser-venomous snakes worth avoiding are the many-horned adder, the horned adder, the desert mountain adder, the coral shield cobra and the speckled shield cobra. Some of their bites may be extremely painful and others may result in respiratory distress that could be life threatening.
Small adder bites often cause severe local swelling with a lot of pain, and recovery takes a week or two.
The majority of snakebites in southern Africa result in pain, swelling and tissue damage, but such bites are seldom fatal. Bites in this category may be caused by snakes such as the Mozambique spitting cobra, puff adder, stiletto and night adder.
Bites from mambas and cobras, especially the black mamba and Cape cobra, cause progressive weakness and paralyse the chest muscles, which affects breathing, and these are the dangerous bites. The onset of symptoms may be rapid and a lack of oxygen soon results in death.
The most important first aid procedure in any snakebite is to immobilise the patient and organise rapid but safe transport to the nearest trauma unit. For people who live far from medical centres, it may be worthwhile investing in a bag valve mask and undergoing the necessary training in its use. If you are hours away from a trauma unit and have to deal with a serious mamba or cobra bite, a bag valve mask, properly used, could mean the difference between life and death.