Why Are Asthma Rates Soaring?: Scientific American

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Breathe deep: Research into varying causes of asthma may eventually lead to new ideas on how to manage the condition.
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Asthma rates have been surging around the globe over the past three decades, and for a long time researchers thought they had a good idea of what might be fueling the increase: the world we live in is just a little too clean. According to this notionknown as the hygiene hypothesisexposure in early childhood to infectious agents programs the immune system to mount differing highly effective defenses against disease-causing viruses, bacteria and parasites. Better sanitary conditions deprive the immune system of this training, so that for reasons that are still unclear, the body pounces on harmless particlessuch as dust and ragweedas if they were deadly threats. The resulting allergic reaction leads to the classic signs of asthma: chronic inflammation or swelling of the airways and acute spasms of those passageways. Read More ...