Venom! What Does It Actually Do Inside Your Body?
Venom is a wonder of nature
Dangerous or not, venom is a wonder of the natural world. It's a poison that animals use in various ways depending on the species. Some animals use it for defence while others use it to catch prey and many use venom for both. For example the spitting cobras- there are a number of species - will spit venom at potential threats to defend itself, but also uses it's venom to kill prey.
However, snakes are not the only animals who have venom. There are numerous species who have this ability such as:
- Amphibians such as frogs and others
- Lizards - such as the Gila monster
- Fish, snails, octopus, jellyfish.
- Insects such as bees, wasps etc.
- Some mammals for example the short-tailed shrew from North America.
- A number of bacteria also carry neurotoxins.
Having said this, not all venom is lethal to humans and there are different types. We'll have a look at these now.
David Attenborough with a spitting cobra
Did you know?
Did you know?
1. Venom and poison are classed as two different things? When talking about venom, this is usually 'injected' into the body by fangs, spines, stingers and so on. When talking about poison this is generally ingested into the body - usually by swallowing or absorbing it through the skin.
2. Many more people die from wasp and bee stings in the USA than from venomous snake bites.
3. Animals can't die from their own venom. It's now believed that many animals such as snakes, make their own anti-venom to prevent being harmed from its own toxins.
Different types of venom
Animals that produce venom have specialised glands inside their bodies, ejecting the toxin through teeth/fangs, spines, stingers. In addition to venom being either a defensive weapon or to catch prey, in some animals it also acts as an aid to digestion.
There are many types of venom, but three of the main groups are:
- Neurotoxins. The medical prefix 'neuro' relates to the nerves of the body and toxin is of course poison/venom. Therefore this type of venom would affect the nervous system. Effects such as suppressing breathing and the heart is common. Other symptoms may include muscle cramps, vomiting, paralysis, convulsions. With this type of venom used to catch prey, it's main aim is to kill by paralysing the lungs and/or heart.
- Haemotoxin/hemotoxin The medical prefix 'Haemo/hemo' refers to the blood and as we've seen previously, 'toxin' is poison/venom. This type of venom then, primarily affects the blood and tissues of the body. It has the ability to break down blood cells and body tissues. In addition, this venom can also affect the major organs of the body. This type of venom frequently causes severe internal bleeding. However, it's not uncommon for blood to also seep out of the body orifices such as the nose, eyes and ears.
- Cytotoxins The medical prefix 'cyto' refers to body cells and as we have already seen, toxin is poison/venom. This type of venom causes spontaneous death of the body cells. The body cells basically explode, releasing the cell fluid and contents into the body. This causes major swelling of the tissues and excruciating pain. In addition, severe damage to body organs and other structures will occur.
Venom itself is a highly evolved form of saliva that contains a rich complex of, sometimes thousands, of various enzymes and proteins. Many of these substances are harmless but others are known as 'super-toxic'. The reason that some venom is harmless while others lethal, depends on both the composition of the proteins and the percentage of toxic proteins within the venom.
We'll take a more in depth look at why venom can be so deadly to human beings.
Did you know?
1. That about 70% of snake bites are 'dry bites'. This means that the snake is trying to scare the threat away rather than do harm by using its precious venom.
2. There are approximately 34,000 species of spider in the world. Although they are all venomous, only about 30 species are harmful to humans. In addition only female spiders are venomous.
Venom and the human body
As mentioned earlier, depending on the type of venom that has entered the body, this will affect specific areas. However, many animals, such as snakes, have compound venom that contains more than one type.
Blood cells in the body
Haemo/hemotoxic venom is a misleading term in a way. Although it does destroy red blood cells, this type of venom also has the ability to damage body tissues.
However, in the first instance this toxin does target the blood, killing off blood cells and also disrupting the blood's ability to clot properly. In order for blood to clot a substance called 'fibrinogen' needs to be present and there also needs to be a good number of special cells called platelets. Haemotoxic venom removes fibrinogen and destroys the platelets. The result in the body is not only severe internal bleeding but damage and failure of tissues and major organs. Death from this venom usually results from failure the heart, kidneys and liver but also bleeding from the brain.
This venom is however generally slow acting, although there are exceptions, and the least common of the venom groups. Death can occur about 24-72 hours after the venom has been injected. The pain can be severe and it's not unusual for amputation of a limb to occur due to the severe damage caused.
Normally when people are bitten there are no signs and symptoms at first. However, after 2-3 hours vomiting, nausea, confusion and headaches begin to develop. In addition, bleeding can be seen coming from body orifices as well as the area of the bite.
Some animals that have haemotoxic venom are:
Naturally, when we look at what this venom does to the human body, we can appreciate why it is so effective when catching the prey. Basically the animals bleed to death or more likely the animal is caught when it goes into shock. In addition, because venom is also used by the animal partly for digestion purposes, it's easy to understand why it does so much damage in the body.
With the viper group of snakes, their venom causes major clots to occur in the main artery leading to the heart with obvious serious consequences.
Neurotoxic venom as the name suggests affects the nervous system of the body. It does this by either damaging nerve cells or blocking the nervous system's ability to communicate. If you think about all the processes that the nervous system is involved with - muscle function, biological functions, proper working of the vital organs and so on, then anything that damages or interferes with the system could have devastating affects. Not only can neurotoxins stop the lungs from working but can also cause cardiac arrest as well as other potentially lethal affects. Needless to say, this type of venom is the most deadly.
In particular a group of snakes known as 'proteroglyphous' snakes such as the king cobra, mambas, some sea snakes, death adders and tiger snakes, can be lethal to humans as they cause respiratory arrest, meaning that your lungs stop functioning and you die by asphyxiation.
The most common symptoms that people will experience are - weakness/numbness in the limbs, problems with vision, memory loss, headaches and paralysis.
Animals that use neurotoxins include:
- Honey bee
- Some species of frog
- Some species of snail
- Some species of tick
- Predaceous Wasp
- Sea anemone
- Puffer fish
General body cells and tissues
Cytotoxic venom is one that attacks body cells. There are numerous reactions that develop when this toxin enters the body. The main one is necrosis. This is basically when body cells and tissue begin to die because of lack of oxygen and nutrients and can have serious consequences, even resulting in death.
When a bite has introduced cytotoxic venom into the body there is severe swelling around the area. In addition, there is frequently bleeding and blistering of the site. This is the reaction seen when necrosis has developed. Vomiting and nausea can also occur as well as loss of consciousness. Another odd symptom is that with some snake bites, people can taste an odd metallic/mint/rubbery taste in their mouth. A the moment I can't find the reason for this symptom despite researching - so if any folks reading this hub know why this symptom occurs then please let us all know.
Animals that have cytotoxic venom include:
- Some species of spider
- Snakes, mostly from the viper group, have this form of venom, for example rattle snakes, puff adder, gaboon viper/adder, spitting cobras.
I hope this hub has been helpful in explaining the effects of venom on the body. However, just remember that animals on the whole - even the venomous ones - are not out to get us. Being cautious, knowledgeable, respectful and having a good dose of common sense is often all that is needed to keep people safe.