Obviously, the microbiomes in the USA aren't causing premature death as frequently as in the zoo, 显然，美国人体内微生物群的失衡，并没有造成像动物园那么多夭折，

　　but we have major risk of obesity, diabetes, a number of these other diseases. 但我们有肥胖、糖尿病和其他类似疾病的高发病率。

　　And this applies not just to people who have been living in the USA for many generations, 不仅是在美国生活了好几代的人存在这样的问题，

　　but also to immigrants and refugees, who, for most immigrant and refugee groups, arrive in the USA metabolically healthy, 而且新移民和难民也一样，多数移民和难民群体抵达美国时，他们在新陈代谢方面很健康，

　　and then within a few years, they become just as high-risk for obesity and diabetes as other Americans. 然后，在几年之内，他们患上肥胖和糖尿病的风险与美国人一样高。

　　And we discussed this issue with two groups that have been coming to the USA from Southeast Asia: 我们与两个从东南亚迁来美国的团体讨论过这个问题：

　　the Hmong, who started coming in the mid-1970s as refugees from the Vietnam War and the US secret war in Laos; 一个是洪族人，因越南战争和老挝美国秘密战争，从20世纪70年代中叶开始，他们以难民身份来到美国；

　　and the Karen, who have been coming more recently as refugees from Myanmar. 另一个是凯伦人，最近才从缅甸来的难民。

　　So we've been working for a few years with these local communities and clinicians 我们已经与这些当地社区和临床医生一起工作了几年，

　　to study what happens to the Hmong and Karen microbiomes when people move from refugee camps and villages in Thailand to the USA. 研究洪族人和凯伦人从泰国难民营和村庄来到美国后，他们体内的微生物群会发生怎样的变化。

　　And what we found is that when people come to the USA from these groups, 我们发现，当这些人来到美国后，

　　they lose a large fraction of their microbiome, somewhere around 20 percent, 他们体内的微生物群失去了很大一部分，约20%；

　　and those who come to the USA and become obese lose about a third of their microbes. 而那些来美国后患肥胖症的人，则失去了（原来）微生物群的三分之一。