Incidence of Helicobacter pylori infection in a cohort of Italian militarystudents

Prevalence and incidence of Helicobacter pylori infection among 250 Italian military students were studied using specific IgG antibodies. Subjects sus ceptible at enrollment were evaluated during a 10-month follow-up period, w hen two serum samples mere collected after 5 and 10 months, respectively. S amples were also analyzed for anti-CagA (a protein associated with virulent H. pylori strains) IgG antibodies, Finally, spectrotypic analysis by isoel ectric focusing and reverse blotting (IEFRB) was performed in the majority of positive samples. Forty-three out of 250 (17.2%) were positive at the ti me of enrollment, a seroprevalence rate very similar to that observed in a larger Italian military population 5 Sears earlier. Among the 207 susceptib le subjects, two seroconverted at 5 months after enrollment; they were stil l positive at the end of follow-up (incidence rate of 1.16 per 100 person/y ears of exposure). This data suggests a spread of H, pylori in the Italian military population that is not negligible. Nearly all anti-H, pylori-posit ive subjects were also CagA antibody positive (agreement percentage: 97.6%; K = 0.91), suggesting that the large majority of H, pylori strains were of the virulent type. Sixty-four percent of positive sera presented an oligoc lonal spectrotype, which seems to be a hallmark of humoral immune response to H, pylori.