This lucid and comprehensive social history of disease in humans is especially pertinent at this time of the Covid-19 pandemic. Karlen shows us that 'parasitism and disease are a natural, in fact necessary, part of life'. Although 'a small number of human diseases have always been with us …, most were once new, … and most of these came from other species.' The consequences are writ large across our history, and new zoonotic diseases will continue to emerge.
He writes, in 1995, 'the twenty-first century will bring a savage test. Infectious diseases remain the world's leading cause of death; they will remain so for a long time to come.' 'Yet [while] there is much in our favour … our most troubling vulnerability is our spotty [sic] record of serving our best interests. Ignorance, greed and shortsightedness will often keep from using the tools we have'. There can be little doubt over the validity of this opinion, given present events.
The message of this book is clear: even if Covid-19 turns out to be controllable, through social control, herd immunity or use of vaccines, there will be another disease, and another - if not next year, then sometime soon. Some will be worse. We would do well to learn the lessons taught by the current (and past) pandemics, to remember them, and to act on them. One clear lesson that is not pointed out by this excellent book is the pressing need to reduce human exposure to animals, particularly wild ones, by stopping their consumption as food and their use for research and entertainment, and as companions.