Posts Tagged ‘Parasites’

DNA transfer between parasite and host

Sunday, May 2nd, 2010

The nature of man’s relationship with parasites has been given a little more indirect illumination by researchers working with a blood-sucking bug, a pond snail and their hosts.

For the first time, these scientists have found solid evidence of the transfer of genetic material between parasitic invertebrates and some of their vertebrate hosts, raising the possibility that bugs and humans may have exchanged DNA by the same mechanism, and that this inter-species exchange of genetic material may have influenced the genomic evolution of both parasite and host.

This work overturns the long-held theory that mammals only obtain genes vertically – from parent to offspring.

Parasites shaped our immune system

Friday, August 21st, 2009

Parasites appear to have been responsible for making some of our immune proteins into the inflammatory defenders they are today but, equally, they have also sculpted some genes into risk factors for intestinal disorders.

Of 91 genes assessed in this study, 44 bore signatures of evolutionary selection, meaning that the genetic variation was due neither to chance nor to the migration of populations over time. And some of that variation correlated with the diversity of parasites that live alongside humans.

In general, parasitic worms appear to have had a more powerful influence on the development of our immune system than smaller microbes such as viruses, bacteria, and fungi, perhaps because of the slower evolution of worms.

More related research here…

We’re still suckers for a Trojan horse

Saturday, August 15th, 2009

As each new piece of technology appears on the horizon, we embrace it without question and add it to the ever-growing collection of ‘must have’ gizmos that adorn our lives. Perhaps, however, we should be a little more circumspect about what we adopt.

When I first moved into a house with an inside loo, I was overcome with joy that I would no longer have to empty my chamber pot each morning into the tippler at the far end of the yard. And our tippler was quite a posh affair – a fully enclosed, brick-built ‘thunder box’, unlike the more usual, ramshackle wooden structures. Users of the latter would relate stories about how they had had their posteriors pecked by hens while answering the call of nature, or prodded with sticks by local miscreants looking for a quick giggle.

An indoor flush toilet was just the most amazing thing, and little did I realise, back then, that this technology might actually be involved in the causation of the eventual collapse of my health, of years of pain, and the loss of a job that I loved dearly. I knew nothing at that time about the effect on the parasitic worm cycle of sanitation and the wearing of shoes, and their consequent relationship with allergy and autoimmune disease.

I never even questioned why I didn’t have worms like those that my aunt had told me she had pulled from her anus on one occasion. I just thought that such things were, like chamber pots and tipplers, ‘of the past’, and good riddance to them! Only now, after reintroducing worms to my intestines and beginning to regain a degree of health that I had come to think impossible, have I realised the price that we in the West have paid for using flush toilets and wearing shoes.

Another contributor to the steep learning curve that I have experienced recently is a realisation about the effects on human health of the plethora of microwave-emitting electronic devices, on which many in the West have now come to rely.

Soon after I installed Wi-Fi in my home, and I began enjoying the freedom provided by this, I noticed that, whenever I used my laptop computer on my knee for any length of time, my legs began to tingle, and this was certainly not due to the weight of the laptop. I wondered if it might be the heat but, eventually, discovered that the tingling stopped when I disabled the Wi-Fi function on the laptop.

This led to a series of related discoveries, including the fact that my DECT telephone was bathing me and my family in microwave radiation 24/7!

The Wi-Fi went into the bin and I switched to a dLAN internet connection which works via the household power main. The DECT phone was replaced by an alternative which only emits radiation when it is actually being used, and I now use a wired land-line phone whenever I can. 

Prompted by this experience, I began to research the whole issue of radio-frequency radiation, and was, frankly, astounded by what I discovered. This article looks at most of the many sources of microwave radiation to which we are now exposed, the effects which these can have on humans, and what we can do to protect ourselves. 

It is now clear that we need to be constantly vigilant when assessing new technologies, whatever form they may take, and adopt a skeptical approach to protestations about safety from manufacturers and representatives of the UK and US governmental and medical establishments in particular, especially as the latter have yet to take any action at all on radio-frequency radiation… and still insist that mercury dental fillings and the fluoridation of public water supplies are both completely safe.

In spite of our obvious technological sophistication, we are still, physiologically, simple hunter-gatherers, biologically unadapted to many aspects of twenty-first century ‘civilization’, such as diet, sedentary working practices, the absence of parasites and exposure to ubiquitous industrial pollution. We ignore this reality at our peril.

Related post:

Cell phones and their threat to health

We may owe the joys of sex to parasites

Friday, July 31st, 2009

An article in the American Naturalist suggests that sex may have evolved in part as a defence against parasites.

Many microbes, some plants and a few reptiles reproduce without sex, and this may seem like a more efficient approach. However, when an asexual creature reproduces, it makes clones – exact genetic copies of itself – and, since each clone has the same genes, it also has the same genetic vulnerabilities which parasites can exploit.

On the other hand, the offspring of creatures which reproduce sexually are genetically unique, so have an evolutionary advantage in parasite-rich environments.

This has been demonstrated in studies of New Zealand mud snails, which come in both sexual and asexual versions. These studies showed that the snail populations which reproduced sexually remained much more stable, whereas clones became more susceptible to parasites over time, and sustained greater losses.

Return of the lost worms

Tuesday, July 14th, 2009

Replacing lost worms to regain health

Helminthic therapy is an experimental approach to the treatment of asthma, allergies and inflammatory and autoimmune diseases, which involves the administration of controlled quantities of selected, benign intestinal parasites such as hookworm and whipworm.

The treatment developed out of understanding gained from scientific studies which showed that, while these illnesses have escalated in developed countries during the past 50-100 years, they remain much less common in parts of the world where intestinal parasites are still prevalent.

The aim of the treatment is to rebalance the host’s immune system by replacing one or more of the harmless organisms which have been lost in recent decades due to improved hygiene, sanitation and lifestyle changes.

The organisms used have become masters of the human immune system during millions of years of coexistence with man and are adept at regulating their host’s immune response. In fact, the codependent relationship between worm and man is so close that the human genome is now arguably incomplete without the genes contributed by these organisms.