Just the mention of a parasite is enough to make most of us cringe. The thought of something else, such as a little worm, making its living pirating the resources within the human body is not a pleasant one (although we all contain vast amounts of bacteria in our bodies, anyway — but these are not considered parasites). Nevertheless, there has been some recent proof that parasitic infection, even though it can still sometimes be harmful, could also be beneficial for some multiple sclerosis (MS) sufferers.
MS is a chronic autoimmune disease, wherein a person’s own immune system attacks their nervous system. The result is the destruction of myelin (an important part of the body’s information highway) and inflammation, leading to many different symptoms such as vision changes, coordination problems, weak muscles, tremor, numbness, speech difficulties, pain, extreme fatigue, and depression. There is currently no cure for MS, although there are treatments that can help with some of the symptoms.
There have been some studies done on animals that found parasites could slow down the progression of the disease. So, Argentinean researchers decided to test out this theory on humans. The study involved 24 MS sufferers, half of whom were infected with a parasite, while the other half were not.
The researchers checked on the disease progression of these patients every three months. Within the final 18 months of the study, they tested the MS patients’ blood to see what kind of immune activity was occurring. This study went on for four and a half years.
The results were quite promising. The MS sufferers with a parasitic infection experienced fewer relapses during the time of the study — in fact, the infected patient group had only three relapses, versus a staggering 56 in the normal group. Moreover, MS progressed slower overall in the parasite-infected group. Weird, huh?
Now, I’m sure you’re wondering what a parasite has to do with an autoimmune disease. Well, many scientists believe that autoimmune diseases have become more common today because we are so well protected as children from infections in general, due to our standards of cleanliness and medical practices. The same is believed of allergies.
Obviously, the key here is the immune system. In this study, the researchers found that levels of certain regulatory immune cells (“Treg cells”) were increased in the MS patients with parasitic infections, but not in those without. It’s theorized that, in order to survive longer in the body, bacteria and parasites have always been able to trigger Treg cells to reign in the immune cells that leap into action to deal with invaders.
Now that our modern practices have limited the possibility of bacteria and parasites living in our bodies, these immune cells can get out of control and end up harming the body. Sounds strange, but it’s a fact that not all parasitic relationships are necessarily harmful — some carry benefits for both the host and the parasite.
The research community has been working on drugs that have the same effect on the immune system, thus helping treat autoimmune disorders. However, this study shows that parasites could be a more natural and safer alternative. The trick now is to figure out how to limit any harmful effects of parasitic infection.