Customer Reviews

Living with Germs: In Sickness and in Health

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John Playfair has done an excellent job with this book. Through a clever use of analogy and anecdote, he makes immunology understantable without feeling dumbed down. The first example that comes to mind is the MHC - major histocompatibility complex - which move material from the interior of a cell to the surface, allowing other immune cells to see what is going on inside the cell. Playfair describes the MHC as a "molecular haulage contractor", and the concept immediately stuck in my mind.

The book starts out with a reality check. We are primed to think that the microscopic world exists solely to make life miserable for humans. This is perhaps a remnant of the ancient religious idea that diseases are a punishment from God. In fact, microbial life forms are simply trying to survive and reproduce, just like us. Most microbes do not cause humans harm, and some are even beneficial to us. Playfair immediately distinguishes the pathogens, those microbes that cause harm to humans, from the rest of the microbial world. He then explains the major groups of pathogen, the bacteria, the virus, the protozoa and the prion.

Intermingled with the story of the immune system is the story of medical history. Playfair describes the antics, quarrels, and mistakes of the great players in immunology: Koch and Pasteur were colleagues somewhat in the spirit of Leibniz and Newton. Like Newton, Pasteur has become the most famous, certainly I remember learning about his "discovery" of bacteria and invention of Pasteurization in school, yet I can't remember hearing much about Koch. Playfair give us several stories of the two men, including their brave (and sometimes reckless) efforts to protect humanity against anthrax and rabies.

The immune system is a complex subject, and after reading this book you will understand more about why this is so. The system has evolved to fight off the pathogens without destroying the body's own cells, and the pathogens have themselves evolved. This necessarily leads to a series of comprimises, and our defenses against the pathogens are multi-faceted, there is no silver bullet to defeat the germs. This balance can sometimes be subtly or not so subtly wrong, leading to immunodeficiency or auto-immune disease.

Fortunately for most of us, with the help of modern medicine we can expect to beat the pathogens in our own lives. There is a note of optimism in the book, and reading it left me impressed by the ability of our bodies to keep us healthy, mostly without us really noticing. The more depressing topics in infectious disease, such as bird flu and the potential return of smallpox, are discussed briefly, but the book does not dwell on speculation. The section on how flu evolves is quite interesting. Playfair explores why flu remains an ongoing problem and explains the meaning behind the ominous code name HN51 (the dreaded "bird flu"). But in the end, as Playfair notes in his introduction, "If I have a message at all, it is simply that you are bound to get infections from time to time, and you are better off knowing something about what is going on. You can then at least decide what to do on the basis of fact and not fear or fantasy."