The analyses indicated that infection intensity and prevalence in the pre-peak of infection group were significantly lower that those in the peak infection group and this was matched by a significant increase in anti-Sh13 IgG3 levels Comparisons between the age groups where infection intensity peaked and declined showed a reduction albeit non significant in infection intensity and prevalence and antibody levels were largely unchanged remaining high as shown in Figure 5. Here, IGHG3 is linked to infection.