Figure 2. Temporal change in transmission parameters The transmissibility values in 1850 yielded a pattern of infection similar to that observed in developing countries today (rapid acquisition in younger ages and lower acquisition in older ages). The rapid decline of transmissibility in the latter half of the 19th century is consistent with GC and DU patterns. Although the graph does not show the decrease in ßAA because of the scale (ßAA is much smaller than ßCC and ßYY), ßAA also decreased over time. Constant extrapolation of transmissibility assumes no change in standards of living that would affect H. pylori transmission.
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