INTESTINAL worms may not be totally bad news. A study of 1600 children in Vietnam suggests that those infected with hookworm are only 60 per cent as likely as uninfected children to be allergic to dust mites (Journal of Allergy and Clinical Immunology, vol 113, p 1305).
While this provides support for the idea that allergic diseases have become more common as children are exposed to fewer infections, it also suggests that theories for how this happens may need adjusting. Bacterial and viral infections stimulate a subset of T-cells called Th1, and the idea was that without exposure to…
