[Epidemiology, acquisition and transmission of Helicobacter pylori]

Helicobacter pylori infection is a chronic infection essentially acquired during childhood. Its prevalence in developed countries like France has decreased according to the year of birth all along the twentieth century, reflecting the progressive improvement of socio-economic and environmental conditions. The incidence of acquisition in adulthood is lower than 0.5% per year. In developing countries, the prevalence is still very high, even in early childhood. H. pylori is a strictly human bacterium. Its reservoir is essentially the stomach. Transmission most likely occurs between humans by an oro-oral or a gastro-oral transmission. Faeco-oral transmission, either direct or via the environment, is possible but seems to be rare in France.