I was alerted twice today to new research suggesting that as infection with intestinal worms, which has been endemic in the third world for millennia, declines, so the incidemce of allergic conditions such asthma and eczema increases – lending weight to the theory that a certain level of parasitic infection controls allergy.
However, it is also accepted that an overgrowth of worms, especially hookworms, can cause ‘severe intestinal blood loss leading to iron-deficiency anemia and protein malnutrition, particularly in pregnant women and children. Chronic hookworm infection in children contributes to physical and intellectual impairment, learning difficulties and poor school performance. This often leads to an under-achieving workforce in already economically depressed communities, thereby perpetuating the cycle of poverty.’
As a result of the above the Bill and Melinda Gates Foundation has now turned its attention to developing a vaccine which will prevent severe hookworm infection in children under 10-years-old living in endemic areas. But… All concerns about yet another vaccine aside, will it only prevent severe hookworm infection or will it eliminate hookworm infection altogether as has effectively been done in the west? Assuming that the ‘low level helminthic infection controls allergy’ theory is right, we could end up with a situation in which very few third world children suffer from anaemia and impaired physical and intellectual development but instead they all suffer from asthma and eczema…
For longer investigation of the dilemma see John Scott’s blog post, Hookworm vaccine: a double edged sword.