Do Our Helminths Make Us Human?

I have written before about the work of Dr. Jamie Lorimer, of Oxford University.  I was very excited yesterday when a friend sent me his newest paper, which examines the history of the helminth/human relationship[i]

A few favorite parts to share with you:

1.  When we first discovered germs, medical science came to view anything not human as evil.  Lorimer quotes a 1962 work that stated that, “…only in a society made up of parasite-free individuals will we know of what the human being is capable.”   Therefore, it became a worldwide medical goal to “disentagled from them.”

Well, what we proved capable of is creating our very own epidemic of inflammatory disease.

2. In the 1980s though, researchers began to notice immunological changes when helminths were eradicated.  “Research on this human microbiome suggests that many core bodily systems and functions have a microbial signature. Metabolism and immunity have been rethought as multispecies processes… and a story is emerging of how mood and cognition are shaped by microbes along a gut–brain axis.”

I love this!  Calling our body functions “multi-species processes” could not be more accurate.  Digestion, immune functioning, development, etc. are all reliant upon not just our DNA, but those of the trillions of organisms that live in us.

Now, not to depress all of you but the grim-reaper in me can’t resist slipping this passage in here:

“But the modern absence of worms can also push the human holobiont [defined in the paper as “dynamic ecology composed of a multitude of microbial organisms”] over an auto-immune threshold, resulting in microbial dysbiosis and amplified host inflammation. A dystopic figure emerges in this narrative of the defaunated modern human, bereft of its microbial kin and living itchy, depressed, overweight lives that are chronically dependent on expensive and unpleasant regimes of immunosuppressant and anti-inflammatory drugs.”

“Itchy, overweight, depressed lives”…It’s unbelievably accurate all too often, isn’t it?

3. Dr. Lorimer goes on to discuss next the controlled reintroduction of our missing macrobiotic worms.

“Humankind eventually needs to move beyond the idea that helminths are best used as a drug or a therapy. Rather, we need to embrace the view that helminths are a necessary component of the ecosystem of a healthy body, and that helminths should be cultivated for population-wide biota restoration. Attempts to develop helminth-derived drugs are, by intent, designed to treat disease, not to restore health to the population. As such, efforts to produce helminth-derived drugs will not help achieve the long-term goals of disease prevention, and may indeed provide a distraction from such goals as they divert resources that could be used for biota-based restoration and maintenance. ”

4. Finally, Dr. Lorimer summarizes the current debate between those who still subscribe to the “germs are bad” viewpoint and those who believe that, “Both the body and the planet are pushing up against or have crossed irreversible tipping points that might bring to an end the very ecological conditions in which human life evolved and flourished.”

The fact that mankind evolved as, and remains, a holobiont is not controversial.  But what native species should reside in us is still a hotly debated question.  If I had to put money on it, I’m going with “Mother Nature knows best.”

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[i] Lorimer, J. Hookworms Make Us Human: the Microbiome, Eco-immunology, and a Probiotic Turn in Western Health Care. Medical Anthropology Quarterly. 2018  Jul 13. doi: 10.1111/maq.12466.