简介：Changestothebacteriathatliveinsideallofusareresponsibleforincreasingthenumberofpeoplewithallergies,suggestsnewresearch. InthisepisodeofHorizon,theshowinvestigatesthisclaimbyconductingauniqueexperimentwithtwoallergicfamiliesinordertofindoutjustwhatitisinthemodernworldthatistoblame.Witharaftofminicameras,GPSunitsandtheverylatestgene-sequencingtechnology,theshowdiscovershowthewesternlifestyleisimpactingtheirbacteria.Whyarethesechangesmakingpeopleallergic?Andwhatcanbedonetoputastoptotheallergyepidemic?…