Roundworm infections can protect against sepsis

History of research on Caenorhabditis elegans

A roundworm, or nematode: Image via Wikipedia

As we’ve learned in Chapter 14, surfaces of the human body are abundantly colonized by a variety of microorganisms, in the absence of disease. This normal microbiota offers us some measure of protection against more virulent microorganisms, through the property of microbial antagonism. Internal tissues of the body, however, are not colonized by microorganisms under normal conditions. The unchecked growth of microbes throughout the body during disease can lead to a profound inflammatory state known as sepsis.

Roundworms are a class of small animals that are very successful as parasites of a variety of hosts, and can cause signs and symptoms that vary from mild to deadly. Examples of diseases caused by roundworms in mammals are heartworm infestations in dogs, and hookworms, whipworms, and pinworms in humans. Although the diseases caused by roundworms can be extremely serious, many of them in humans are more chronic in nature, leading to a situation where people become infected and carry the parasites for an extended period of time. These infections are typically acquired and transmitted via the fecal to oral transmission route. Consequently the frequency of these infections is lower in the United States and other developed countries, however they are endemic in many parts of the world.

Well, here’s something that may cause you to rethink your aversion to eating undercooked meat. According to the summary from Science Daily, researchers at the University of Liverpool and other institutions have found a species of roundworm can work to prevent sepsis. Their finding have been recently published in the journal Nature Immunology. Sepsis is part of the body’s response to a massive systemic infection, and involves an out of control inflammatory response that ultimately results in significant damage to the body. Inflammation is triggered by the presence of the microorganisms, and although the microbes can cause tissue damage as they grow, the damage caused by the inflammatory response is more significant in the short term. The researchers have found that a protein called ES-62 made by nematodes is able to diminish the shock response by apparently blocking the body’s ability to signal for inflammation to occur. Professor Alirio Melendez states in Science Daily:

“The protein secreted by the roundworm stimulates a process called autophagy, a process of ‘self-eating’ that is essential to clear damage to cellular proteins or organelles and promote cell survival and function during stress situations.

“Autophagy reduces inflammation but at the same time permits the clearance of microbial infection. The findings suggest that ES-62 could be used to induce autophagy and reduce the overwhelming inflammation that is responsible for the massive tissue damage seen in sepsis.”

When administered to mice even after the introduction of septic shock, mice were protected from the harmful effects of sepsis.  This may have immediate potential benefits for therapy: there are not any adequate treatments for septic shock today, other than emergency supportive care for the patient. If ES-62 is as potent of a suppressor of inflammation as it appears to be in the animal model, it may provide a critically needed form of therapy.

BONUS:  The benefits of worms in human health are things that I’ve brought into BIO230 before. Either by hitting up Pubmed, or by asking someone who’s been in BIO230 before this semester, how else have roundworm infections been proposed to be beneficial?

About ycpmicro

My name is David Singleton, and I am an Associate Professor of Microbiology at York College of Pennsylvania. My main course is BIO230, a course taken by allied-health students at YCP. Views on this site are my own.

Posted on March 12, 2011, in Bonus!, Lecture, Microbes in the News, You are what you eat. Bookmark the permalink. 4 Comments.

  1. I did some research and found a study, conducted on children, in which worms may help to protect against house-mite allergy. Worms have a way to “tone down” human immune systems to help prolong their stay in our bodies. Scientists have found out that over millions of years, “co-evolution” worms have found new methods to tone down our immune systems. The relationship between the two have become so intertwined that “without worms (gut worms) and other parasites, our immune systems could become unbalanced and could contribute to the development of asthma and other allergies. Dr. Carsten Floher, a Clinical Scientist, conducted a study in which children positive for worms were repeatedly given a tablet to try and treat the worms. Overall, the outcome of the study was that there was no effect with asthma, but a large amount of children developed a positive allergy of the skin from house dust mites and cockroaches.

  2. Brittany MacFadden

    By reading through the article, I found that it stated that the protein that’s secreted by the roundworm initiates autophagy which is when the organism eats itself to “clear damage to cellular proteins or organelles and promote cell survival and function during stress situations. When this autophagy occurs, it reduces inflammation and also begins to get rid of the infection. I found an article on Pubmed that supported this reduction of inflammation proposal. The article by M. Harnett stated that there is “increasing evidence supporting an inverse relationship between worm infection and T helper inflammatory disorders such as rheumatoid arthritis, inflammatory bowel disease, type 1 diabetes and multiple sclerosis.” This study resulted in the ability of worms to modulate inflammatory responses to promote parasite survival, has also produced the benefit of protecting the host from pathological lesions arising from aggressive preinflammatory responses to infection or, inflammatory responses underlying autoimmune and allergic disorders. This study focused on theES-62 filarial nematode-derived immunomodulatory molecule which demonstrated the benefits of this worm for inflammation.

    • The medical literature actually has a fair number of reports of the immunomodulatory properties of helminthic (worm) infections. The actual basis of the immunomodulation is not clear at present, but I will tell an interesting story in a few weeks about a clinical trial that I think we might have a tough time finding people to enroll in here at YCP!

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