Monday, February 24, 2014

Hygiene Hypothesis and Helminthic Therapy

Hygiene Hypothesis and Helminthic Therapy

The parasites are usually recognized as notorious creatures which infect and damage hosts’ bodies, even though they do not mean to harm the hosts—they are merely trying to survive and continue their generations. However, this is not always true. Recent studies suggest that some parasitic worms may be useful in treating autoimmune diseases such as Crohn’s disease or allergies.

Hygiene Hypothesis
Autoimmune disease refers to the abnormal functioning of one’s immune system that cannot differentiate self-tissues and other tissues. This leads to one’s antibody attacking one’s own body. One possible cause of this disease can be explained with the hygiene hypothesis, which states that early life exposures to germs decide the sensitivity to allergic and autoimmune diseases. In fact, the more advanced countries with better hygiene systems with less exposure to germs have an increasing rate of autoimmune diseases.
So, what effect do germs, including parasites, have on the immune system? They trigger the Type 2 helper T cells by tickling proteins called cytokines, which initiate a healing process. However, if there are not enough germs in the body, then the immune system would attack its own body instead of the germs, and this leads to inflammation and diseases.

Trichuris trichiura—great for Helminthic Therapy
Trichuris trichiura

One of the best parasites that were found so far would be Trichuris trichiura, also known as whipworms. This is usually found in humans or pigs and is known as a great treatment for Crohn’s disease. This disease affects any part of the gastrointestinal tract and causes inflammation. This creates symptoms such as diarrhea, rectal bleeding, fever, etc. Whipworms are great to be used since they do not cause any serious damages in human body even though they are still parasites. Also, they are big enough to be recognized by immune system, and the antibodies would attack the whipworms instead of its own body tissues. This in fact results in 75% of cure of Crohn’s disease.

Even though the use of helminthes significantly increased of cure of autoimmune diseases, some scientists still doubt about the safety.  They argue that parasites are parasites and they may cure some diseases, but they also may cause other problems, so it has to be studied a lot further. It also needs to be very carefully used.


  1. I find it interesting that "The Art of Being a Parasite" claims that households that use antibacterial soap tend to experience the same amount of illness as those using regular soap. In my mind, I would think that they would experience fewer occurrences of illness. It's so ironic that a parasite, by definition, an organism that EXPLOITS, can actually IMPROVE the well-being of an organism. At the same time, I think we do have to ensure that a line is drawn. Americans are known to discover that benefits of something and overdose. The fact that these helminths are beneficial doesn't suggest that anyone should make it a daily routine to ingest parasites in an effort to ward off symptoms of illness.

  2. Another example of the hygiene hypothesis can be found in the book "Riddled with Life". After doing research in Germany, Dr. Mutius found that children were less likely to suffer from allergies and asthma if they lived in a more polluted environment. Her experiment is supported by the hygiene hypothesis, because children actually need to live in less clean environments in order to have immune system stimulation. I feel like most parents who have children with asthma and allergies will keep their kids inside more often than kids who do not have allergies or asthma. The parents are fearful of an onset occurring. However, this is actually just preventing the children's immune system from learning to defend the child. The immune system has to have the chance to distinguish between actual pathogens and pollen.

  3. After learning about the hygiene hypothesis, I was finally able to understand my parents view on illness such as asthma and allergies, which are more prominent to developed countries rather than developing countries. My parents both grew up in India, and when they came to the United States, they did not understand why some many children had trouble breathing and were allergic to simple foods such as peanuts. Myself, I could not understand how they never heard of allergies or asthma when they were living in India. Now looking at the hygiene hypothesis and understanding that exposure to certain parasites is crucial to avoiding these illness, I finally understand why they never heard of these illnesses before. In India, and other developing countries, children are exposed to unsanitary conditions on a daily basis, and in the process were able to form the mechanism to avoid getting asthma and allergies. I believe that we should take into account the hygiene hypothesis and understand that a little dirt never really hurt anyone.