撰文\播音：克里斯托弗·因塔利亚塔（Christopher Intagliata）
翻译：Ada
审校：潘磊
When Europeans arrived in the New World, they carried with them microscopic, deadly organisms… like smallpox, measles and flu… which caused devastating outbreaks among the indigenous people.
One of those outbreaks was what became called the cocoliztli epidemic of 1545, among the people known as the Mixtecs, in what is today southern Mexico. The victims suffered rashes and fevers; blood streamed from their eyes, noses and mouths. Millions died. But we're still not sure what caused it.
当欧洲人抵达新世界时，他们还带来了一些致命的微小生物……引起了比如天花、荨麻疹、流感……这些病原体的流行造成疾病在土著居民间近乎毁灭性的爆发。其中一次爆发于1545年。在米斯特克人（位于现墨西哥南部）中爆发了一场病灾，历史上称之为cocoliztli epidemic。患者们在炎症和高烧中煎熬，血液从眼睛、鼻子、嘴巴里沁出。数百万人死去，但是时至今日我们仍不能确定是什么引发了这次灾难。
So scientists looked to 10 victims, buried in communal graves in one of the afflicted towns, for clues. They sequenced DNA from within their pulpy tooth cavities. Most studies of ancient bones ditch all the associated microbial DNA, so that only the host’s DNA is analyzed. But in this case the bacterial and viral DNA were the stars of the show. Which also meant a lot more genetic data to sift through.
科学家们仔细检查了十具掩埋在受难小镇公墓中的尸体，希望找到一些线索。他们从尸体牙洞的糊状物中提取出DNA，并对其测序重组。大多数研究会把古骨中微生物相关的DNA除去，只分析主体的DNA。但是在他们的研究中，细菌和病毒的DNA才是主角。这也意味着更多的基因数据需要被筛查。
"The difference is the needle in the haystack." Noreen Tuross, a biochemist at Harvard University. "This is a much bigger haystack."
Using a new algorithm to help them dive into that huge haystack, they found a needle: genetic evidence of the deadly Salmonella enterica Paratyphi C bacterium, which causes enteric fever.
The results are in the journal Nature Ecology & Evolution. [Åshild J. Vågene et al., Salmonella enterica genomes from victims of a major sixteenth-century epidemic in Mexico]
“这些基因数据中的差异就像是掉进干草堆的一根针。”哈佛大学的生物化学家诺林 图罗斯这么说。“这个干草堆比想象的大得多。”通过使用一种新的算法，深入这庞大的“干草堆”，他们终于找到了那根针：危险的沙门氏菌Paratyphi C bacterium感染的基因证据，正是这种细菌引发致命的肠热病。研究结果发表在《自然·生态·进化》（Nature Ecology & Evolution）杂志上。
The researchers stopped short of pinning the epidemic on the salmonella alone. "Could there have been other organisms around? Yes. We didn't find them. How do you know that what you didn't find isn't there? That's ridiculous."
研究人员并不止于把流行病的起因完全归于这一种沙门氏菌。“是否存在其他有机体作用其中？完全有可能。我们还没有发现它们。我们怎么能因为没有发现就认为它不存在呢？那太荒谬了。”
And it's uncertain the disease had European origins—though there is evidence it existed in Norway, three hundred years before Columbus sailed. But this effort arms archaeologists with a new tool to study not just great civilizations…but also the world of microbes with which they coexisted.
而且这个病是否根源欧洲也不能确定。虽然有证据显示，300多年前哥伦布还没有起航的时候，挪威就存在这种疾病。但另一方面，这些研究为考古学家提供了一种新的研究思路用来考察文明的变迁……也是一种探寻那个与人类共生的微生物世界的新方式。
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