Many people seem to live under the impression that we are apart from nature rather than a part of nature, and, encouraged by advertisements exhorting us to rid our homes of 99% of bacteria, we strive to live in 'sterile' conditions.
In fact, our bodies are mobile homes to a multitude of creatures that were around long before us and will no doubt be around long after we may have gone. However, as our living conditions and personal hygiene have improved, they have had to adapt and have become even more wily and tenacious.
The following is a quick guide to the most common human skin parasites. Get ready to itch - and get ready to pull to mind stories of night-dwelling, blood sucking creatures that prefer young girls!
Head lice are often referred to as ‘nits’ although the nits are actually the oval yellow-white eggs that the louse lays glued to the hair shafts. They are tiny, eat skin and have clamp-like hands to prevent removal. They actively prefer the long clean hair of young girls’ and their intimacy with their companions as a route of direct transfer from scalp to scalp.
They are more common in Caucasians because of the hair type and although unpleasant, do not carry diseases - unlike some other lice.
Although head lice can affect other hairy parts of the body, they most often confine themselves to the head. They feed on human blood and itching from louse bites is a common symptom of this condition and usually intensifies during the night about 3-4 weeks after initial infestation. The bites may most easily be seen in the hair at the nape of the neck. Symptoms of infestation may also include feeling run down, irritability and a mild fever.
There are hundreds of different types of body lice all adapted to their specific conditions. Whereas head lice attach themselves to hair, body lice will often attach to clothing. They are small and thin, eat skin and, having no anus ultimately die of constipation! Body lice can transmit diseases such as typhus and although controlled by modern hygiene can return as a potent human skin parasite with a vengeance in times of famine or war.
Pubic lice or ‘crabs’ are the most common and widely distributed human louse. They are visible to the human eye, being about the same size as sesame seeds (2 mm) and are tiny and grey but become brown when swollen with blood. Like other lice, they too display an alarming array of clamps and hooks with which to resist removal. They can also affect eyebrows, eyelashes and armpits and whilst they do no real harm, they can be transferred by intimate contact.
The scabies mite
The scabies mite belongs to the spider family and, whilst the mites that cause scabies are too small to see, the itchy red lumps they produce as they burrow into the skin can be easily seen. The scabies mite has 8 legs, serious jaws and they both lay eggs and excrete waste products into their skin burrows and it is this that is responsible for the intense itching which is typically worse at night. The females can also die within their burrows whereas the males tend to get washed away. For reasons that are not entirely clear, the skin of the wrist, elbow and groin are most often affected.
Bedbugs belong to the insect family and for some reason which may have to do with hermetically sealed, centrally heated homes, they are the human skin parasite that is currently enjoying a renaissance. They are visible (being up to 5 mm in length), brown, flat and oval and have hairs that may give them a banded appearance. They live in the nooks and crannies of soft furnishings and, averse to daylight, emerge mainly at night to feed on human blood. They have 6 legs and and a beak containing two feeding tubes – one to inject saliva containing anticoagulants and anaesthetic and the other to draw blood.
Somewhat remarkably they reach their host by scaling the walls and/or ceiling and then drop down on to their host when signalled to do so by warmth and the presence of carbon dioxide. Once they have fed, they return to their hiding place. Most people are unaware of the bites at the time, although some react later to the substances injected. Whilst they are capable of going a remarkably long time between feeds, most bedbugs feed once a week or so.
Bedbug bites may look like mosquito bites, but do not have not red dot at the centre and may last longer. They may also occur in clusters of three as the bed bug searches for a suitable vein! The substances that the bedbug injects may also cause anxiety, stress and insomnia. Although unpleasant, this human skin parasite does not carry any diseases.
Fleas are small (approx 2 mm), dark, wingless insects with tube-like mouth-parts adapted to feeding on the blood of their hosts - preferably young women. Capable of jumping 18 cm, this translates to the comparable ability in humans of being able to leap over sky scrapers!
They have a very tough outer shell which makes them remarkably resistant to crushing. They are averse to sunlight and live in crevices where they lay eggs that then pass through several different stages before their cocoons are signalled to hatch by the vibration, heat or carbon dioxide generated by a passing human. Some people have an allergic reaction to the flea saliva which can remain for many weeks. Fleas are one of the human skin parasites that do carry disease, for example, the bubonic plague and typhus fever are both carried by fleas.
The fungi that live on our skin feed on the keratin in dead skin cells and are shed along with them. They prefer warm, moist environments. Shown here is an example of ringworm which can be caused by several different fungi and forms rings with raised borders.
It is estimated that one in five people has a ringworm infection at any given time! Use of corticosteroid creams may suppress the reaction shown, but not stop the ringworm from growing.
Bacteria live on the fats and oils in our secretions and prefer warm, moist places such as sweaty feet and the groin. The number of bacteria on one person's skin at any time is thought to be equal to the total number of people that ever lived. The vast majority of bacteria help to decompose waste and so prevent larger scavengers. Your bacterial flora also determines your unique personal odour.
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Human skin parasites: Article summary
This article looks at the most common human skin parasites including lice, fleas, bedbugs, the scabies mite, fungi and bacteria. It examines their life cycles and symptoms likely to indicate infection.
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The Natural Recovery Plan Newsletter April 2010 Issue 4. Copyright Alison Adams 2010. All rights reserved Dr Alison Adams Dentist, Naturopath, Author and Online Health Coach www.thenaturalrecoveryplan.com