It is a long-held convention that maladies such as cancer, lung diseases, and cardiovascular diseases are non-communicable and cannot be transmitted from one person to another. This prevailing understanding may not be the case suggests a new study.

Researchers from the Canadian Institute for Advanced Research (CIFAR) hypothesise that the microbiome may cause the transmission of non-communicable diseases between people. They posit that microbes such as viruses, bacteria, and fungi—that live on and within the human body—can transmit diseases that are said to be non-transmissible.

"If our hypothesis is proven correct, it will rewrite the entire book on public health," said Dr Brett Finlay, lead author of the study, in a statement.

Accepted knowledge about common non-communicable diseases

OBESITY
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The most common non-communicable diseases that account for 70 percent of deaths across the world include cancer, lung disease, and heart disease. It is believed that they are caused by a combination of factors such as lifestyle, environmental factors, and genetic defects. Therefore, they are not considered communicable diseases.

However, if the hypothesis is proven, it can have a profound effect on the treatment of diseases and public health in general. "This paper provides a provocative new way to think about non-communicable diseases, with important implications for public health," said Alan Bernstein, CEO of CIFAR.

The hypothesis that challenges convention

Making connections between three pronounced lines of evidence, the researchers presented their hypothesis in the paper.

They began by showing that individuals suffering from various conditions such as obesity, type 2 diabetes, cardiovascular disease, and inflammatory bowel disease, have mutated microbiomes. Following this, they demonstrated that when altered microbiomes from diseased people are introduced into animal models, the animals develop diseases.

Lastly, they presented evidence to suggest that these microbiomes are transmissible naturally. The researchers presented the example of spouses who have more similar microbiomes as they share a house, as against twins who live separately. "When you put those facts together, it points to the idea that many traditionally non-communicable diseases may be communicable after all," said Finlay.

Proving the hypothesis- The next step

Despite the hypothesis challenging the existing norms surrounding non-communicable diseases and the excitement it has generated, the researchers point out the deeper intricacies of the mechanism require further exploration. Encouraging other researchers studying diseases to take into account the effect of microbes, Finlay concluded, "We hope the paper will inspire further research into the mechanisms and extent of communicability."