Humanity has had major problems with infection since the agricultural revolution about 10,000 years ago, when larger communities living at permanent sites with domesticated animals experienced much greater exposure to pathogens. From then until the nineteenth century, infectious disease caused mortality patterns where half of children born were dead before the age of 5 and half of the remaining population before the age of 40. This mortality pattern had a major influence on human society promoting belief in life after death or in repeated reincarnation. Many religious prescriptions with regard to diet, personal hygiene and sexual behaviour probably survived because of their effect on preventing infection. With the advent of public health, vaccination and antimicrobial therapy, this situation has been transformed in the last century. This has contributed to an enormous increase in population and the consequences for the future of humankind are discussed.