The research began around the notion that perhaps kids develop asthma because the places in which they grow up are too germ-free. "If children are exposed to microbes that stimulate their immune systems in the first few years of life, they will be protected against asthma, the hypothesis says. As asthma rates climbed, researchers published study after study supporting what has become known as the hygiene hypothesis," Kolata notes.
This particular study began when a group of researchers noticed stark differences among two
seemingly similar groups: the Amish of Indiana and the Hutterites of North Dakota. Asthma affects only 2 to 4 percent of the Amish, Kolata writes, but affects 15 to 20 percent of the Hutterites. The groups are very similar in genetic background, diet and lifestyle. "There was one difference, though: farming methods," Kolata explains. "The Amish live on single-family dairy farms. They do not use electricity, and use horses to pull their plows and for transportation. Their barns are close to their homes, and their children play in them. The Hutterites have no objection to electricity and live on large, industrialized communal farms. Their cows are housed in huge barns, more like hangars, away from their homes. Children do not generally play in Hutterite barns."
|A Hutterite dairy farm in North Dakota|
After analyzing the dust from Amish and Hutterite homes, researchers found that Amish dust was packed with debris from bacteria; Hutterite dust was not. Researchers sent the dust to Dr. Donata Vercelli, an associate director of the asthma and airway research center at the University of Arizona, for testing in mice. "She put dust — Amish or Hutterite — into the airways of mice 14 times over a month and then exposed the animals to allergens," Kolata explains. "We found exactly what we found in the children," Vercelli told Kolata. "If we give the Amish dust, we protect the mice. If we give the Hutterite dust, we do not protect them."
The impact could be far-reaching. Dr. Talal Chatila, an immunologist at Harvard Medical School, told Kolata, "It is not far-fetched to start thinking of how one could harness those bacteria for a therapeutic intervention."