Missing old friends

Tuesday, January 9th, 2018

Modern humans may be missing old friends:

With good reason. Hookworms are a leading cause of disease in the developing world with around 750 million people suffering from infection, which can cause anaemia, growth retardation and malnutrition in heavily infested populations. Hookworms can even be lethal, with hookworm related death standing at an estimated 60,000 people per year (Crompton 2002, de Silva 2003).

In first world nations, cleanliness, sanitation and clothing measures have eradicated hookworm infections by breaking their life cycle. (Brooker 2004, Crompton 2000)

This may seem like a good thing at a casual glance. The economic impact of hookworms is huge for some countries. For example, productivity losses due to hookworm infections in South Asia have been estimated at a value of approximately 5 billion dollars annually. (Crompton 2002) At first glance, exterminating these parasites seems wholly sensible.

There is a caveat however, to throwing nature out of balance by Man’s crude intervention. By vastly overpopulating areas in developing countries, we have created the perfect conditions for huge hookworm burdens. Then, by removing hookworms completely, we induce conditions unnaturally sterile. Our bodies, finely tuned through eons of evolution to respond to the challenge of parasite infection, react erratically.

Westernised nations have witnessed a dramatic rise in the incidence of chronic inflammatory and autoimmune diseases, a rise that is concurrent with hookworm eradication. Researchers soon realised that many autoimmune diseases are largely absent in Third World populations. This discovery gave rise to the Hygiene Hypothesis.

The Hygiene Hypothesis theorises that the absence of various micro-organisms in Western society causes dysfunction in immunoregulation (Stiemsma 2015, Versini 2015). We see this manifest itself in diseases such as MS, Crohns disease, Asthma, and Rheumatoid Arthritis. This theory can be traced back to the 1870s when it was noted that aristocrats and city dwellers were more likely to get hay fever than farmers.

This idea was further developed into the ‘Old Friends Hypothesis’.

Whilst it would be rash to state that the sole cause for the increase in autoimmune diseases seen in our society is due to helminth eradication, it is certain that the underlying cause in genetically susceptible individuals is environmental. One of these environmental factors is the removal of Helminths, or ‘old friends’ (Rook 2012).

In Rooks’ words:

“The Old Friends hypothesis suggests that one reason for the increasing incidence of chronic inflammatory disorders in developed countries since the mid-nineteenth century is the depletion from the urban environment of organisms that accompanied mammalian evolution and had to be tolerated. In parts of the world where there was a heavy load of organisms causing immunoregulation (such as helminths), there has been selection for single nucleotide polymorphisms (SNP) or other gene variants that partially compensate for the immunoregulation. As soon as immunoregulation inducing organisms (Old Friends) are withdrawn by the modern lifestyle, the genetic variants lead to excessive inflammation, and become risk factors for chronic inflammatory disorders”

In effect, organisms like helminths have been present in the human environment since the evolution of our species. Our immune systems have been titrated to their presence. Further, genes have evolved to help to manage the burden of these organisms, genes which predispose individuals to autoimmune disease once the helminths have been removed.

The fellow writing about old friends suffered from terrible psoriasis and decided to try Necator Americanus therapy:

A few short weeks and a lot of reading later, I sat at home, looking, with serious trepidation, at a small vial filled with clear liquid.

Inside it, were 25 stage L3 NA Larvae, purchased online with laboratory assurance that they were as sterile as a multicellular organism that comes from faeces can be.

Now I am not by nature someone who puts off what needs to be done. But I won’t lie when I say it took a few minutes of serious contemplation before I pipetted the innocent looking fluid onto the supplied dressing, and pressed it onto the skin of my inner arm.

Would this work? Did the larvae survive transit? Would they find their way onto my skin?

I needn’t have worried, less than two minutes after application, it felt like dozens of hot needles were boring into my skin. This was very real, and now there was no going back. They were inside me.

I didn’t sleep that night such was the itching on my arm, and I got a low grade fever the next day that lasted 48 hours.

Exactly 5 days post inoculation, I awoke in the middle of the night thinking someone was choking me. My throat was burning and closing up fast, causing my breath to rasp in my chest. As I sat in the bathroom gasping for breath, I knew exactly what was happening. They had made it to my throat and were about to finish their migration down into my intestines.

10 days after inoculation, I awoke once again in the early hours of the morning to terrible stomach ache. My regular regimen of intermittent fasting was out, the only remedy for this was a large breakfast, which for reasons unbeknownst to me helped ease the symptoms. My skin, likely because I had stopped the Methotrexate, worsened.

Bereft that I might have to drag my arse back to the Dermatologist and actually ask her for worming tablets, I toughed it out.

It worked.


  1. Graham says:

    That description sounded gross and more than a little unnerving, but I suppose any port in a storm.

    Perhaps we need a happy medium- as long as we have control of our parasite load and which ones they are, perhaps it’d be for the best.

    The Old friends thesis is certainly interesting. I’m only dimly aware of it. But down the last few decades I had wondered which of the emergent major health concerns of the age were:

    a) actually new
    b) growing in prominence because people were no longer killed faster by other stuff
    c) just finally getting attention but formerly just subsumed in eons of things like unexplained premature death, mutation, or regarded as madness.

    Many I still don’t know- autoimmune diseases seem to be a bit of a at least in terms of their new scale and frequency, and a bit of b. I guess that includes food allergies too, as well as asthma, both of which seemed to have been increasing rapidly since my 70s childhood.

    I even wonder, from a different category, where autism fits in. There are many areas where removing parasites from our lives is reported to have improved everything including mental function. But I suppose that doesn’t have to be a universal truth.

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