Helicobacter pylori and TT virus prevalence in Japanese children

Background. The major transmission route of Helicobacter pylori, oral-oral or fecal-oral, remains to be established. TT virus (TTV), a recently discovered microbe that is prevalent in healthy persons, is believed to be mainly transmitted by nonparenteral routes. The purpose of this study was to test the hypothesis that these two microorganisms have a common mode of transmission. Methods. We investigated the seroprevalence of H. pylori and TTV in a cross-sectional study of 454 healthy Japanese children from birth to age 15 years, living in five different geographic areas. Determination of H. pylori status was based on the presence of specific serum IgG and IgA antibodies, determined using enzyme immunoassays. TTV DNA was detected and the titer was determined using semiquantitative polymerase chain reaction with heminested primers. Results. The overall prevalences of H. pylori and TTV were 12.2% and 21.6%, respectively. An age-related increase of prevalence was shown for H. pylori (P < 0.001), but not for TTV (P = 0.23). Titers of TTV DNA significantly decreased with age (P = 0.02). There were significant geographic differences in TTV prevalence (P < 0.001), but not in H. pylori seroprevalence (P = 0.33). There was no true correlation between the prevalence of these two organisms ( coefficient = -0.02 and P = 0.66). Conclusions. Although Japanese children frequently acquire both H. pylori and TTV, especially in early childhood, their acquisition appears to be independent.