Over the last few hundred years’ tremendous advances have been made in the treatment and eradication of many diseases, especially in developed countries. Human life expectancies have increased dramatically in many parts of the world. However, infectious diseases are still widespread and there is a continual rise of non-communicable diseases, the so called “diseases of civilization” such as heart disease. Additionally, due to the widespread use and overuse of antibiotics since the introduction of penicillin in 1943, we are experiencing a re-emergence of infectious diseases, with pathogens that are antibiotic-resistant and have the potential to be transmitted on a global scale.
Moreover new diseases are emerging in human populations; for example at least 22 in the last 30 or so years as listed by The Centers for Disease Control including; Rotovirus, Ebola virus, Legionella pneumophila (Legionnaires Disease), Hantaan Virus (Korean hemorrhagic fever), HTLV I, Staphylococcus toxin, HIV, Human Herpes Virus 6, Hepatitis C, and Hantavirus isolates.
The World Health Organisation’s (WHO) current projection for 2105 is out of a world population of about 7.2 billion, there will be a total of 60,856,000 deaths with 13,705,000 accounted for by communicable diseases, maternal and perinatal conditions and nutritional deficiencies, and the remaining 41,193,000 caused by non-communicable conditions such as cancer, cardiovascular disease, neuropsychiatric disorders, etc. Only recently have the ideas of “Darwinian medicine” received serious interest among most evolutionary biologists and students through the introduction of courses in universities and medical schools. This book will discuss the origin and nature of disease, by taking a holistic view which gives the reader significant insight into the evolution of disease, and provide reasons as to why disease will continue to be part of human existence. Ultimately why diseases can exist and are successful is because all living organisms have a common origin and a common molecular basis. For instance the coevolution of viruses and eukaryotic cell mechanisms such as DNA replication is only just being understood. Viruses may have originated by “escaping” from the cellular environment, eventually becoming selfish self replicating elements. Even more interesting is the suggestion that DNA replicating proteins, and even DNA itself, in eukaryotic cells may have had a viral origin. Although the notion maybe upsetting to some, disease in humans has always been present and probably always will be as a result of our common biological heritage with all other organisms on Earth.