Some day, doctors may prescribe worms to help treat people with autoimmune diseases such as Crohn’s disease, rheumatoid arthritis or type 1 diabetes. Humans and their parasites have co-evolved through the millennia, but now in countries where intestinal parasites are rare, some pathways of the immune system may go awry. In parts of the world where such worms are common, autoimmune diseases like lupus or Hashimoto’s disease are fairly rare.
Doctors are experimenting with the short-term use of live parasites or substances that they secrete to retrain the body’s response to inflammation. There is hope that eventually this could even be beneficial in cases of inflammation linked to heart disease or allergic reactions, such as those triggered by the introduction of titanium or other metals in artificial joints. The challenge now is to find a way to control the immune system’s reaction to the parasites we no longer host.
The concept of our co-evolution with unseen life forms that inhabit us was explored in a very entertaining fashion by Rob Dunn, in The Wild Life of Our Bodies.