Thu Apr 16, 2015 2:47 pm
Snakes in Your Bed
There is a great deal of speculation about how people are bitten by snakes and one figure that is often quoted is that more than 6,000 people are snakebite victims a year in Southern Africa. Snake lovers are quick to claim that most people are bitten while trying to kill snakes while others think that the majority of victims are snake enthusiasts or keepers that get bitten while capturing or handling a snake. Compared with the total number of bites, snake handlers make up a very small percentage of snakebite victims – probably less than 3%.
We know that the vast majority of snakebite victims are rural people that get bitten when they accidentally stand on a snake or perhaps while working their land, usually barefoot. Most bites happen on warm summer days or nights, often after rain and the vast majority of victims are bitten on the lower leg followed by bites on the hand and arm. The Mozambique Spitting Cobra accounts for the majority of serious bites but very few result in fatalities. Second on the list is the Puff Adder followed by the Stiletto snake. Fatal bites are quite rare and we have not had a fatal bite from a Stiletto snake. The Black Mamba and Cape Cobra account for most fatal bites mainly because of their fast-acting venom that causes progressive weakness and that affects breathing.
It is common knowledge that the vast majority of our snakes are quick to move off when encountered with exceptions like the Puff Adder and Gaboon Adder – they remain very still and rely on their excellent camouflage to avoid detection. And if you are 5 m or further away from any snake you are perfectly safe – there is no snake in Southern Africa that will approach you from five meters away and attack you. Not even a Black Mamba.
Having said that, we are seeing more and more cases of people being bitten while asleep in their beds. This is most puzzling and the logical explanation has been that the snake enters a bed in search of warmth and when accidentally rolled on, strikes out in self-defence. Nice theory but appears to be way off the mark and for a few reasons. Firstly, in well over 95% of such cases the snake responsible is the Mozambique Spitting Cobra (Naja mossambica), also the snake responsible for most serious snakebites especially in Zululand and Swaziland. They are common and actively hunt their prey which consists largely of frogs, rodents and other snakes but they eat just about anything that they come across.
We know that with defensive bites the snakes often give a quick bite without injecting venom, the so-called ‘dry’ bites. Or even when venom is injected in defensive bites, there is usually very little envenomation. But in most of the bites in beds we are seeing severe envenomation and in many cases the victim will have more than one bite. These bites are inflicted on the hands, arms, body, and face and even on the eyes. And although it is largely rural people that are bitten, often while asleep on the floor, there have been a number of tourists bitten while asleep in their bed at a luxury game lodge.
In recent weeks there have been numerous cases of people being bitten by Mozambique Spitting Cobras whilst asleep and many of them children. It appears that the snakes are ending up in houses, either accidentally entering through the gap under perimeter doors of perhaps going into houses in search of food – with their forked tongue they are able to locate prey such as rodents or frogs from great distances. Once inside the house these snakes are crawling up onto beds and then biting people who are asleep. The only logical explanation, and we have debated this at length, is that they are mistaking the victims for food and biting with intent, often more than once.
Their venom is potently cytotoxic and victims must be hospitalised urgently and usually need antivenom. The longer it takes to get to a hospital and the right treatment, the worse the effects of the venom and victims often end up with severe necrosis that requires surgery. We are very keen to run a series of experiments to try and establish exactly why these cobras bite sleeping people and hope to start soon. In the interim, make sure that your doors seal well and that you cannot push a finger into the gap under a door – that will be a big enough gap for a cobra to enter. Even better, put mosquito doors on all your outside doors – snakes seldom enter houses through open windows.
Thu Apr 16, 2015 7:41 pm
Thu Apr 16, 2015 8:34 pm
None of the Sanparks cottages will be safe, there is always a hole somewhereIn the interim, make sure that your doors seal well and that you cannot push a finger into the gap under a door – that will be a big enough gap for a cobra to enter. Even better, put mosquito doors on all your outside doors – snakes seldom enter houses through open windows.
Thu Apr 16, 2015 8:46 pm
Thu Apr 16, 2015 8:54 pm
Fri Apr 17, 2015 3:12 pm