Science, medicine, and the future: Helicobacter pylori and gastric diseases

Abstract

Changing epidemiology of H pylori H pylori is one of a large family of related bacteria that are well adapted to persist in the stomachs of vertebrates for the life span of their hosts. It is likely that H pylori has colonised our stomachs since well before we became humans.4 Studies of primates and human populations in developing countries suggest that, until the last century, nearly all humans carried H pylori or closely related bacteria in their stomachs. H pylori can thus be regarded as indigenous or “normal” flora, which most humans acquire within the first few years of childhood and then carry for life. With socioeconomic development, fewer children are acquiring H pylori.5 This is a worldwide phenomenon that seems to have preceded the introduction of antibiotics, although it may have been accelerated by their widespread use. The reasons for the decline in the prevalence of H pylori colonisation are unknown. Improved nutrition and clean water have been proposed. An alternative hypothesis is that most transmission is from child to child and that declining family size reduces the opportunity for transmission and increases the age of acquisition. In developed countries, for perhaps the first time in the human experience, large numbers of people are now passing their lives without H pylori colonisation. This is a crucial observation with considerable relevance for understanding the changing pattern of gastrointestinal diseases.