The remaining study population are either currently infected (indicated by the presence of parasite eggs) or have had previous infection and are now putatively immune (indicated by the absence of parasite eggs in combination with the presence of parasite-specific immune responses associated with resistance to infection such as anti-worm antibodies (IgE, IgG1, IgE/IgG4 ratio) and parasite specific cellular responses (IL-5) as previously reported [25, 58, 67]). This evidence concerns the gene IGHE and infection.