Disease Contagion? Nay!

"It really leads to a rather almost heretical postulate -- that non-communicable diseases, which basically means non-infectious diseases, might actually be communicable."
"And, given that 70 percent of the people in the world die of what we call non-communicable diseases, it gives you a whole different way of looking at these things."
"...Your microbes are more similar to the person you're living with than the genetically related twin living on the other side of the world."
"Intimate contact for sure leads to spread of microbes."
"[Technically obesity ranks as a non-communicable disease, the leading risk factor for heart disease, Type 2 diabetes] and pretty much every non-communicable disease you can list."
"I'm sure there will be naysayers and the hardest part is uncoupling environmental factors from microbial changes [since evidence increasingly suggests obesity has a microbial component]."
"But we need to recognize that microbes could be a contributing factor. Which is a whole new way of looking at these diseases in terms of health policy and how we control them."
Brett Finlay, microbiologist, microbiome researcher, University of British Columbia

"Your microbes are more similar to the person you’re living with than the genetically related twin living on the other side of the world."   Getty Images

This week's issue of the journal Science features a paper postulating that according to increased data, cardiovascular disease, type 2 diabetes, and irritable bowel syndrome along with other conditions considered by the medical community to be non-communicable; not transmissible from person-to-person, might in actual fact spread by means of microbes. This is, granted, a theory, an educated guess, in the realm of possibility as yet, given the need for more collaborative research.

Dr. Finlay (who wrote Let Them Eat Dirt: Saving Your Child From an Oversanitized World), along with colleagues -- fellow members of the Canadian Institute for Advanced Research, explain the progress of their study and its conclusions. They point out that people living with chronic diseases also have a "dysbiotic" (other-than-normal) gut microbiota in comparison to those of healthy people, disease-free.

Stool taken from people with non-communicable conditions such as heart disease, diabetes and obesity, transplanted into healthy, germ-free mice -- rodents that have been raised in extremely sterile environments -- result in the animals tending, as a consequence, to develop the same diseases as those from whom the stool derived.

Researchers who analyzed gut and mouth bacteria from close to 300 villagers living in the Fiji Islands revealed in a study published last March that people living in the same households and spouses particularly, held similar strains in their gut microbiota. "You could basically figure out who was married to whom based on the microbes", Dr. Finlay stated.

Although non-communicable diseases are responsible for global deaths totalling 41 million in number, the definition of an "NCD" (non-communicable disease) denotes it to be highly unlikely that any spread of disease through microbes occurs; the causation instead focuses on genetic, environment, and lifestyle factors, write the researchers.

Trillions of bacteria, fungi and viruses thrive in and on the human body. How's this for perspective: one gram of feces, roughly the size of a fingertip, contains microbes as numerous as people on the globe. The role of these microscopic life forms links to digestion, immune response, metabolism, brain development and other functions: in short, they are indispensable to human health. Now they're also being credited with a darker side.

Most of the microbes exist in the lower gut. And how's this for a sobering statement?: 80 million microbes can be transferred person-to-person with a single kiss. Studies in mice have discovered that thin mice can be transformed to become obese, and vice versa by means of fecal transplants between obese and lean mice.

It is only rational to conclude then that obesity may also be transferable in humans. A study published in 2007 that involved over 12,000 people found that a 57 percent higher chance of becoming obese was related to having an obese friend. The researchers wrote that diabetes also might have a "communicable component". As, for example, within a year of a diagnosis of diabetes, spouses gain a higher chance of developing diabetes as well.

People married to and living with partners with irritable bowel syndrome also are considered to have a higher rate of the disease than can be explained only by chance.

"India has very low rates of IBD [irritable bowel syndrome]. They move to Canada, U.S. or Britain and they have some of the highest ethnic rates we see, period."
"And so that’s not genetics. It could be they are acquiring microbes from the developed countries that make you much more prone to diseases."

Microbes play a role in many critical functions. Getty Images

"You can't change your genes, but you can easily change your microbes" through diet, exercise, probiotics, perhaps one day via fecal transfers, or even by moving to another country, Dr. Finlay noted. "Any environmental change results in a microbial change."

"This paper provides a provocative new way to think about non-communicable diseases, with important implications for public health."
"Ideas like this are a great example of what happens when top researchers from around the world work together in an environment of trust, transparency, and knowledge sharing."
Alan Bernstein, president, CEO, Canadian Institute for Advanced Research (CIFAR)