Influenza: That Ever-Evolving Beast
If you’re reading this and are at a respectable adult age – over 30, let’s say – you’ve likely suffered a bout with the flu a few times over the years. We all picture it differently, but you’ve surely had your own unique vision of the microscopic monster that infects us and causes extreme nausea, aches and pains, and so many other nasty symptoms; I personally lean towards a marauding green beast trampling over my insides.
Luckily, we don’t need to leave anything to the imagination where the influenza virus is concerned, and it is this fact that has allowed us to get such a great handle on its evolution over time – and what that evolution means to us. Because it is so common – various forms of the flu can affect some species of both birds and mammals – the influenza virus is one of the best understood pathogens where evolutionary science is concerned.
While we can appreciate the flu’s quick and pointed ability to mutate by evolutionary means, the potentially devastating flip-side of that process is the fact that this virus is able to infect new hosts at a fast rate, making keeping up with it difficult from a scientific point of view. Despite most developed nations routinely vaccinating their populations against new strains of the flu, even our most persistent efforts haven’t allowed us to escape the recent waves of H1N1 (swine flu) and H1N1 (bird flu) infections, serving as proof positive that staying on top of influenza’s rapid evolution is a full-time job.
How Does Flu Evolution Work?
All organisms on the planet, humans included, are the result of a long series of small genetic mutations that have taken place over the course of billions of years. This fact, while well-known by the public at large and well-understood by the scientific community, is rendered almost useful in everyday terms given the unimaginable time scales involved. The massive time periods required to see meaningful evolutionary change are the result of both the small mutations and the relatively long periods of reproduction exhibited by most species, making it difficult to observe them.
Luckily, viruses of all forms buck this trend, reproducing so quickly that we’re able to observe deep changes in their structure over even a single human lifetime. This is due to the relative simplicity of a virus, making even small changes meaningful, and the fact that viruses are able to reproduce using material harvested from its host, allowing them to create copies of themselves quickly and efficiently before moving onto the next host.
Given its never-ending effect on humanity, and its potentially dire consequences, studies on the evolution of influenza have been many and wide-ranging, mapping out the techniques used by the virus to alter its composition in order to better adapt to new hosts. Among those studies, one published in 2010 seems to have nailed down the key to this rapid mutating: a well-maintained, exceedingly fine balance of generating enough mutations to suit many new environments, without producing so many that catastrophic mutagenesis, the term given to a virus that produces so many genetic mutations that it renders itself ineffective and dies, occurs.
It’s this balance that gives the virus the ability to equip itself with the genetic tools necessary to infect a variety of environments, and this is the key to their ability to occasionally make the leap from one host to a vastly different one; for example, the scarey jump from birds and pigs to human beings seen over the past decade.
The Importance of Viral Evolution
After making it this far, you may find yourself asking exactly why understanding the way that influenza evolves is important. You’ll get different answers to that question from different people, but my view is threefold:
- Given that evolution is the driving force behind our very existence as complex, intelligent, self-reflecting, investigative human beings, the topic seems a worthwhile one to lend a bit of brain time to.
- Because the influenza virus is able to copy itself so quickly and efficiently, not requiring the typical period of gestation and lifecycle that slows the process of evolution to a crawl in more macroscopic animals, it is one of the very best examples of Darwin’s principles in action, giving us more insight into how life changes over time than any other creature on Earth, save the fruit fly.
- Understanding the evolution of viruses like influenza is doubly important given the potentially deadly effects that it can have on us. Whether we concern ourselves with the awful, but relatively harmless, bouts of illness that many of us face due to the virus during the winter months, or the possibility of a worldwide pandemic with the potential to kill millions of people, influenza and humans are clearly at odds in our evolutionary world, and you know what Sun Tzu said in his famous The Art of War: know your enemy.
With these points in mind, you can see just how unique the common flu is, and how useful the data it provides us with can be in keeping us healthy, on a variety of scales!
Conclusion
In the end, I hope that I’ve been able to entertain you, teach you something about an age-old enemy, and convince you that evolution is a very important topic when it comes to life in general, and human health in particular. Assuming I’ve succeeded, I hope to see you again next week – same time, same place!
