Why fighting disease is hard

Without a doubt, medicine has made tremendous gains over the last decades and even more progress when viewed across centuries.  Often to treat diseases, physicians and researchers identify a single or primary pathway that is causing the disease.  Maybe there is a gene mutation which causes an abnormality.  Maybe there is a bacteria or virus that is invading the body.  Typically, we look for a single disease cause and identify treatments to that can address this root cause.

Things get much more complicated, however, when disease a disease is caused by numerous factors.  Consider the following example from the book I Contain Multitudes: The Microbes within us and a gander View of Life, examining the case study of researcher Herbert Virgin and his analyses of mice with genetic mutations for Crohn’s disease.

These rodents developed inflated guts, but only if they were infected by a virus that knocked out part of their immune system, and were exposed to an inflammatory toxin and had a normal set of gut bacteria.  If any of these triggers was missing, the mice stayed healthy.  It was the combination of genetic susceptibility, viral infection, immune probles, environmental toxin, and their microbiome that gave them IBD [Irritable Bowel Disease].

Identifying multiple root causes is complex.  In this case, by addressing one of these causes, IBD could be cured.  In practice, however, sometime there many be cases that without addressing all causes, the individual may not recover normal health.

This complexity certainly makes for interesting research for scientist, but also highlights that perhaps medicine has only begun to address the low hanging fruits.  While there is much potential to further cure human diseases, doing so will likely become increasing complex.

As a side note, I do recommend the by I Contain Multitudes book by Ed Yong.  The book describes how bacteria act symbiotically in both positive and negative ways with humans, other animals, and other organisms as well.  The book highlights some recent research, while presenting the content in a non-technical manner.  I found it an enjoyable read to introduce non-biologists to the importance of the microbiome.