If the authors are correct, doctors will prevent allergy by infecting babies with germs that grow in the intestines to stimulate the intestinal immune system, so it won't feel neglected and have to go out and attack dead things like pollen, dust mites, and animal dander. British Medical Journal February 12, 2000. OS VonEhrenstein, E VonMutius, S Illi, L Baumann, O Bohm, R VonKries. Reduced risk of hay fever and asthma among children of farmers. J Riedler, W Eder, G Oberfeld, M Schreuer.
Austrian children living on a farm have less hay fever, asthma and allergic sensitization.
Conclusion Possible explanations for the lower prevalence of hay fever, asthma and allergic sensitization in children living on a farm might be the development of immunotolerance or the stimulation of TH1 cells and suppression of TH2 cells by increased exposure of farm children to microbial antigens in the stables or farmhouses. M Kilpelainen, EO Terho, H Helenius, M Koskenvuo. Farm environment in childhood prevents the development of allergies. Environmental exposure to immune modulating agents, such as environmental mycobacteria and actinomycetes, favouring manifestation of a nonatopic phenotype could explain the finding. J Elms, LJ Allan, I Pengelly, D Fishwick, PN Beckett, AD Curran.