Take Ecological Approach to Fight Human Disease, Study Says

November 27, 2012 - News Release

Why do some patients become more ill than others? How might controlling weight gain or smoking help a patient fight off harmful strains of viruses?

Doctors looking for answers to better treat disease might brush up on their ecology smarts, say University of Guelph authors of a novel study published online this month in PLOS ONE.

Carmen Lia Murall, a PhD student in the Department of Integrative Biology and the paper’s lead author, said few studies have looked at human disease as an ecology problem. Her co-authors are integrative biology professor Kevin McCann and Prof. Chris Bauch, Mathematics and Statistics.

Their study might also help doctors and researchers learn more about how disease organisms, notably “super-bugs,” elude drugs and vaccines.

The researchers looked at infectious diseases as food webs. Normally McCann and another ecologists build food webs to describe “who eats whom” in the wild.

In this study, the researchers considered the human body as an ecosystem, with food webs made up of pathogens, human cells and the immune system.

Using math and computer models, they modelled competition between virulent and more benign strains of influenza, human papilloma virus (HPV) and human immunodeficiency virus (HIV). They also looked at how behaviour such as smoking affected competition among viral strains.

Their model was able to predict outcomes for all three afflictions.

Certain strains of microbes dominate under some conditions, but others compete better when the environment changes.

McCann said looking at the internal “balance of nature” involving pathogens, host cells and the immune system might help explain what happens after a patient with HPV or HIV changes behaviour, such as smoking cessation.

Taking a food-web view might one day help doctors in treating disease.

Referring to the emergence of personalized medicine, Murall said, “This research fits with where health is going already -- having a better idea of who the patient is and whether they are more likely to get a disease or a more persistent infection.”

This approach may also give ecologists ways to study ecosystems in the laboratory as well as in the field. “We study food webs of all kinds. It turns out food webs are in the human body in a sense,” said McCann.

The integrative biologists have discussed this “human ecosystem” approach with U of G microbiologist Emma Allen-Vercoe, who studies probiotic foods and treatments intended to promote beneficial gut bacteria. Said Allen-Vercoe, “Microbial ecology will likely become an important medical specialty in the near future, as we continue to discover how much influence our microbes have on our health.”

Said Bauch: “Research disciplines often make great strides when ideas developed in ostensibly unrelated disciplines are applied to them. We hope that the same will be true when ecological theory is applied to what happens in the microcosm of our body.”

For media questions, contact Communications and Public Affairs: Lori Bona Hunt, 519-824-4120, Ext. 53338, or l.hunt@exec.uoguelph.ca; or Shiona Mackenzie, Ext. 56982 or shiona@uoguelph.ca.

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