| changes in seroepidemiological pattern of helicobacter pylori and hepatitis a virus over the last 20 years in japan. | the age groups most susceptible to infection and the mode of transmission of helicobacter pylori (h. pylori) are not yet clear. to contribute to a better understanding of this disease, this study was undertaken to evaluate changes in the seroepidemiological pattern of h. pylori in a group of japanese people over the last 20 yr sampled in 1974, 1984, and 1994 in comparison with that of the hepatitis a virus (hav), which was used as a marker of the fecal-oral route of transmission. | 1999 | 10445533 |