Environmental Microbiome Role in Development of Allergies and Asthma

There is accumulating evidence from population-based and experimental studies to suggest that the microbiome could play a significant role in the development of asthma and allergies. These studies used novel DNA-based sequencing techniques, which conferred a deep insight into the microbial diversity in the environment as well as on body surfaces. The environmental microbiome indoors is determined to a great extent by outdoor exposure and to a significant extent also from human and animal home occupants. The strongest evidence for an important role of the environmental microbiome for protection from asthma and allergies comes from studies enrolling farm and non-farm children. These studies have consistently and repeatedly shown a significant reduction in asthma and allergy risks in farm children who are exposed to an environment rich in microbes. In these environments protection is conferred not by one microbe but more by a cocktail of bacteria and fungi. The strongest effect has been seen among children from Amish populations, which live a very traditional farming lifestyle. Among these children hay fever is almost non-existent, atopic sensitization about 6aEurofold lower than among children living in German cities and virus-induced wheezing lower respiratory tract diseases do not progress to allergic asthma.