It happened in a moment yet the effects will be felt forever.
On Friday in Japan, one of the largest ever recorded earthquakes happened. The event itself took only a fraction of a second, the shaking and rolling lasted about a minute and within the hour, there was a horrific tsunami that left some 500 square kilometers of Japan inundated in water and caused billions of dollars in damage. In addition. the coastline moved 8 feet and the earth’s axis shifted about 10 centimeters.
This is evolution at its extreme. And, I believe it can help us all appreciate how a much smaller entity, a germ, can evolve over time and lead to significant, costly and potentially disastrous consequences.
The evolution of this earthquake has been a focus of news agencies and other people who want to understand what exactly happened. At it’s most basic level, the quake was caused by a culmination of continuously small and insignificant movements between the North American and Pacific tectonic plates combined with one significant environmental stressor that at the time seemed innocuous.
Each movement between the two plates led to environmental stress and an increase in potential energy. Over time, the plates needed to release some of this stress and accomplished this through a combination of smaller earthquakes and in some situations, volcano eruptions. However, in this case, a completely unsuspected environmental stressor, namely the 7.2 earthquake two days earlier, led to both molecular and geographical changes in the area and that triggered the giant earthquake and tsunami.
When this occurs, there is no turning back; the earth has been irreversibly changed.
With all this now in place, one might wonder how any of this can translate into the evolution of germs. Yet, when one looks at the concept of environmental stressors and an unsuspected trigger, a link not only can be made but also may demonstrate why what we do in everyday life can affect germs and eventually us.
It may not be easy to appreciate but inside each germ, there is a similar set of ‘plates’ that define the germ itself. These plates are the genetic material that encodes the proteins that allow the germ to function. At the molecular level, DNA is continuously in movement and may mutate on a regular basis. This process of mutation, much like the potential energy, is caused by environmental stress such as low nutrient supply, altered physical environment and the presence of antimicrobials, such as antibiotics, disinfectants and antiviral agents.
Mutation rates are normally quite low and the development of an insignificant mutant, sometimes called a spontaneous mutant, may be similar to that of a smaller earthquake. These mutations occur on a regular basis yet many either do not survive or have little impact on the environment.
In certain cases, the environmental stressors may contribute to a more stable mutation that could lead to the evolution of a new trait, such as antimicrobial resistance. As has been shown over the last 40 years, this form of evolution can be associated with an increase in the use of environmental stressors, such as antibiotics.
Then there is the ‘big one’, in which a globally significant mutation would occur through a combination of environmental stressors and a potentially innocuous trigger. There have been three such mutations over the last 30 years and their names are anything but unknown.
SARS, Pandemic Influenza and HIV.
These three viruses are mutants of lesser pathogenic viruses that have circulated the globe for centuries. Yet, for some reason, each of them faced the right amount of environmental stress, and one or more triggers that brought about mutation and survival. Thankfully, SARS and pandemic influenza have been stopped. However, HIV continues to spread and cause significant morbidity and mortality worldwide.
There can be no doubt that continual vigilance to predict to the next ‘big one’ is a priority for all of us. And several are on the radar. Could malaria and dengue fever become endemic in cooler climates? Extremely drug resistant tuberculosis already exists but could there be a mutation in the future that renders all treatments futile? The H1N1 pandemic was nothing like its predecessors; could there be one in the future that out-rivals them? And what of the Toxoplasma gondii parasites that normally cause little to no infection in healthy individuals that suddenly found a way to kill?
Unfortunately, as it is with earthquakes, it can be almost impossible to predict when the next evolution will occur and what the impact may be. Which is why we need to be as diligent as possible when it comes to our health and hygiene.
Over the next little while I hope to provide some global perspective on how something as simple as handwashing can be fundamental to stopping evolution by preventing germ spread and infection. I hope to share stories of programs and interactions that have helped some of the most vulnerable individuals maintain their hygiene and their quality of life. And I hope that theses examples will help to develop a picture of how small, easy actions can keep the environmental stressors down and prevent the potential for a trigger that could lead to a major evolutionary shift and lasting consequences.