????專家警告稱，對于一些鼠疫已經在小范圍流行的地區來說，氣候變化很可能會加劇鼠疫爆發的風險，新的危險區也有可能隨之出現。但目前這還只是猜測。斯坦瑟斯及其同事在《PLOS醫學》（PLOS Medicine）雜志上撰文指出：“人們對鼠疫病菌在天然宿主體內的發展及其變異對人體的風險所知甚少。國際社會應該比現在更加重視鼠疫問題。”

????是的，在黑死病大爆發幾百年后，這一史上最著名、被反復研究的瘟疫依然籠罩在神秘之中。與此同時，我們對“傳染”這個過程本身的了解也遠遠不夠。比如說打呵欠也是會傳染的，再比如說我們的情緒、面部表情、記憶、辦公室的活力，乃至全球銀行系統，都容易受到傳染力量的影響。

????問題是，對一種傳染形式的研究是否有助于我們了解其他傳染機制？比如通過研究病菌的傳染，能否有助于我們研究金融危機的傳染？（1997年和1998年的經濟危機又分別叫做“亞洲流感”和“俄羅斯病毒”。）抑或，通過研究“集體情緒傳染”（即情緒如何在個體間傳染），能否有助于我們預防自殺的“井噴”？

????抱著這樣的愿望，《財富》（Fortune）決定探索各種事物的傳播機制。我們邀請五位作者深入探究了傳染的幾種表現形式——有些是比較熟悉的，比如病毒的全球傳播；有些則有點不太尋常，但我們收集了相關論文（見下方鏈接）。

????在兩篇文章中，埃瑞卡?弗萊首先調查一種在沙特阿拉伯爆發，名叫MERS-CoV的冠狀病毒，是如何從蝙蝠傳染到駱駝、再從駱駝傳染到人類，最后又出現在印第安那州孟斯特一家小型社區醫院的。這種病毒是臭名昭著的SARS病毒的近親。就在全球正在緊張關注正在西非部分地區肆虐的埃博拉病毒之際，弗萊向我們展示了為什么MERS-CoV可能具有更大的蔓延風險。

????珍?韋茨納和史蒂芬?甘代爾分別從不同方面研究了股市傳染病。韋茨納首先深入研究了并購圈的謠言傳播路線圖，展示了一次簡單的猜測如何演變成引發股市震蕩的流言。具有多年金融報道經驗的甘代爾則深入探究了股市上一個多年未解之謎——為什么在沒有任何重大負面消息的情況下，會突然出現大范圍的拋售股票？換句話說，大家的“恐慌按鈕”究竟是如何被人按下的？

????如果你想知道“逃亡”一詞是如何跟“暢銷書”聯系起來的，不妨閱讀一下安妮?范德梅評論2014年暢銷書——托馬斯?皮凱蒂的《21世紀資本論》（Capital in the Twenty-First Century）的論文。杰西?亨佩爾則研究了另一個熱門的社會現象——“自拍”。據亨佩爾研究發現，“自拍”的迅速泛濫，既受到科技革命性變革的推動，同時也出于人性的沖動和自戀。最后，埃瑞卡?弗萊又把研究對象轉移到了研究者自己身上，闡釋了為什么研究Twitter等社交媒體也變成了一種流行的學術行為。歡迎了解大學校園內最熱門的學科之一：《Twitter學入門基礎》。

????網絡的力量既讓我們與地球村聯系得更加緊密，也使這些“傳染病”傳播得更加迅速。這張看不見的網已經成為我們日常生活中密不可分的一部分。從理論上講，每名Facebook用戶只需要發送一個交友申請，就可以跟另外13億人成為朋友。LinkedIn上的近3億用戶，只需要輕輕一點，就可以聯系上一個老同事，找到一個新的職業機會，認識一個陌生人。

????即便是用傳統意義界定的“人際交往”來看，人們之間的交往也比以往更加緊密了。今年，全球有30多億人次要通過飛機出行（根據去年的數據）。每次“云端之旅”都有可能讓你認識一個陌生人，或者與其他人交換一些東西——比如一次對話、一張名片、一杯不小心溢出的咖啡，或者一種隱藏的病菌。

????中世紀的黑死病再次進入我們的視野。這樣一種蔓延極廣，橫掃了將近700萬平方公里區域的流行病，居然發生在飛機、汽車、火車出現的好幾百年之前，這實在令人震驚。（的確如此，由于黑死病傳播速度之快、范圍之廣，有些專家甚至懷疑我們或許認錯了對象，或許當年爆發的是另一種更致命的、通過空氣傳播的病毒。）

????在當今世界，我們離整個世界的距離也許只有一封電子郵件、一個YouTube視頻、一張飛機座椅那么遠。在了解（以及想象）傳染病將如何在這樣一個時代傳播方面，我們只是剛剛邁出了第一步。不過在本系列中，一些令人耳目一新的觀點已經開始掀起傳染的神秘面紗。（財富中文網）

“傳染”系列文章：

【傳染之一】比SARS更致命：蝙蝠病毒MERS是如何成為人類殺手的

【傳染之二】“自拍”何以變成社會流行病

【傳染之三】市場拋盤是怎樣發生的？

【傳染之四】并購傳聞如何不脛而走

【傳染之五】從賈斯汀?比伯到數據學家，Twitter何以成為一門顯學

????譯者：樸成奎

????Experts have warned that climate change might increase the risk of outbreaks in areas where the Y. pestis bacillus is already endemic and that new danger zones may emerge. But it’s all guesswork now. “Remarkably little is known about the dynamics of plague in its natural reservoirs and hence about changing risks for humans,” wroteStenseth and his colleagues in the journal PLOS Medicine. “Plague should be taken much more seriously by the international community than appears to be the case.”

????Yes, centuries after the Black Death, the actual illness at the center of the most famous and studied pandemic in history remains shrouded in mystery. And, importantly, so too does the process of contagion itself, a cascading ripple effect that turns out to be everywhere. Our yawns, our moods, our facial expressions, our memories, our office dynamics, our global banking system are all subject to the forces of contagion, it would seem.

????The question is, whether studying one manifestation of the process can shed light on another. Can researching the way pathogens spread, for instance, help us understand financial contagions? (It may be telling that financial crises in 1997 and 1998 were known, respectively, as the “Asian Flu” and the “Russian Virus.”) Or can making sense of “group emotional contagion”—how moods are transferred among individuals in, say, an office or on a sports team—give us insights into preventing “outbreaks” of suicide?

????With such aspirations in mind, Fortune set out to explore how various things spread. We asked five writers to delve into seven manifestations of contagion—some familiar, as in the global spread of a virus; some, a bit unusual—and we’ve gathered their essays here (see the links below).

????In a pair of posts, Erika Fry begins by investigating how a deadly new coronavirus, the MERS-CoV, emerged in Saudi Arabia, traveled from bats to camels to humans, and ended up in a small community hospital in Munster, Indiana. As the world nervously keeps watch on the epidemic of Ebola, now raging through parts of West Africa, Fry shows why the Saudi coronavirus (a cousin of the infamous SARS virus) has, perhaps, a greater potential to spread.

????Jen Wieczner and Stephen Gandel each probe different ends of stock market contagion: Wieczner takes us deep inside the corporate takeover rumor mill, showing how the thinnest reed of conjecture can quickly become stock-jolting gossip; and Gandel, a veteran financial reporter, dives into one of the enduring mysteries of the market—what triggers a sudden broad stock selloff when there’s seemingly no precipitating news? In other words, how exactly does that collective “panic button” get pushed?

????If you’ve ever wondered how the term “runaway” ever got hitched to the word “bestseller,” then read Anne VanderMey’s essay on Thomas Piketty’s Capital in the Twenty-First Century, the bonafide nonfiction contagion of 2014. Jessi Hempel, meanwhile, takes a turn exploring another, surprisingly durable, social fad: the “selfie.” As Hempel discovers, the meteoric rise of the insta-self-portrait is due as much to transformative changes in technology as it is to human compulsion…and, well, narcissism. And finally, Erika Fry returns to investigate the investigators: showing how studying viral trends on Twitter and other social media got to be such a viral academic specialty. Welcome to Twitterology 101: the hot ticket on campus.

????Adding fuel to each of these contagions is our ever-growing web of connections to the global village, with the virtual tethers now so much a part of our daily lives that they no longer surprise. Every Facebook user, in theory, is just a single friend request away from some 1.3 billion others. Each of nearly 300 million LinkedIn members is a mere click away from an old colleague, a new professional contact, a stranger’s query.

????Even when it comes to that old-world concept of human contact, we are more interconnected than ever. Consider the more than 3 billion passengers in the world who will likely travel on an airline this year (based on last year’s figures). With each voyage in the clouds will come an opportunity for a new link or exchange with a stranger—a conversation, a business card, a spilled coffee, a stowaway germ.

????Which, again, puts the Black Death of the Middle Ages in stark perspective. That such a far-flung pandemic—blanketing an area of roughly 7 million square kilometers—could happen centuries before the invention of the airplane, the car, the truck, or the train is astounding. (Indeed, the uncanny speed and scope of its spread has led some experts to wonder whether perhaps they’ve fingered the wrong pathogen in that outbreak, and whether the real driver might have been a more readily airborne virus.)

????We are, of course, just beginning to understand (and imagine) how contagion may manifest in an age when each of us is potentially just an email, or YouTube video, or middle seat away from the rest of the world. Here, some eye-opening perspectives on how it has revealed itself so far.