More on the Helminth-Microbiota Connection

I just finished reading a pretty dense – but seriously interesting– paper[i] describing research on the interactions between the microbiota and multiple species of helminths in wild rodents.

Their findings are fascinating.

1. Firstly the researchers confirm that the presence of helminths in the gut is “linked with high microbial diversity, which may confer health benefits to the host.”
2. What the researchers found, that is novel, is that each helminth species was associated with specific variation in the composition and abundance of certain types of bacteria.
3. Changes occurred up and down the digestive system, and were not just localized to the area the helminth inhabited.
4. The most pronounced association between helminths and the microbiota was between rodent tapeworm (Hymenolepis) and a particular type of bacteria in the stomach. Hymenolepis, in general, showed the “strongest association with microbiota composition” of all the various helminths, and these alterations ranged from the stomach to the colon.

The authors point out that since our microbiota is so crucial to health (in that it helps absorb and generate vitamins, regulates cognition and behavior, protects us from pathogens, is fundamental in the development of the immune system and the prevention of autoimmune disease), the implications of these findings may be vast.  In fact, it is possible (actually likely) that helminths’ ability to modulate our immune systems may be the result of both direct effect on our immune systems and indirect, via changes in the microbiota.

A few other particularly interesting points in this paper:

1. The authors point out that natural helminth colonizations maintain microbiota diversity – and inoculation in parasite-free hosts restores this lost diversity.
2. The number of helminths present does not seem to affect the types of microbiota present.
3. Hymenolepis, as it has the strongest association with alterations in the microbiota, “may have significant effects on host physiology and health status.”

Whether or not there is an optimal type of helminth or helminths to exactly modify the human microbiota is decades of research in the future.  In the meantime, we do know at least that the presence of helminths improves the quality of the gut microbiota in humans.

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[i] Kreisinger, J, Bastien, G, Hauffe, HC, Marchesi, J, Perkins, SE. Interactions between multiple helminths and the gut microbiota in wild rodents. Philosophical Transactions of the Royal Society B. 2015:370:20140295.