If biological evolution had its way, we would be living for around 40 years, which was round about the average lifespan that modern humans have had for the vast part of their existence on earth. Disease was nature’s way of ensuring that our species evolved, through the survival of the best genes that could cope with it, while the rest gradually passed into oblivion.
However, human evolution over the last two centuries have been at its most accelerated pace if we take into account our social and psychological evolution as well. Human longevity in many parts of the world have touched the early eighties and still on the rise.
The evolutionary battle against viruses and bacteria best bring out these social and psychological evolutionary aspects. While many forms of infectious disease have been virtually eradicated through vaccination and hygienic methods, newer forms have been ‘naturally selected’ which are far more resistant to our collective species’ wisdom of using antibiotics, vaccines and antibodies. If there were no antibiotics, would there ever have been any penicillin-resistant bacteria ? I doubt it – the records do not show that. The pattern of fighting has changed – the constantly mutating microbes now face a global network of scientists, doctors and other humans who are dedicated to root them out.
Chronic illnesses too have been caught up in this evolutionary battle. We now know that we are far worse adapted to survive in the midst of plentiful food than in a situation of moderate short supply. The fight against obesity is again another story in our species’ evolutionary history, trying to cope with the effects of overabundant food supply for the first time in our history on such a massive scale.
The evolutionary race between humans and disease has always been there, only now, we have entered a rapid, accelerated phase. The expression of disease in most cases reflects a state of maladjustment with our environment; and successful adaptation leads to our progress on the evolutionary pathway, only now that its definition and scope are both considerably expanded.
It would appear that at present, we humans are winning the race.