New from NPR! 禽流感情勢稍緩，但仍不可掉以輕心!

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從現在開始，NPR除了提供聲音檔，也提供文字解析版。直接點選下面的標題，可以前往NPR官網連結。

我花很多時間整理這些文章，目的是希望讓大家更有效率的閱讀與訓練聽力。歡迎大家多使用部落格文字，多跟你的好朋友說，我希望每個人都下載，免費學到英文，越多人下載越好，這樣我花時間就非常值得了。今天這篇分享的是禽流感。之前我也跟大家分享過birdflu的相關文章，因為想要搞懂禽流感的N跟H到底代表什麼，還去找了資料，請大家看完文字檔繼續看我提供的補充(是中文)。
加油吧，這篇聽六遍，好好K單字，你的聽力一定會進步。

Scientists Race To Stay Ahead Of New Bird Flu Virus

From NPR

This is WEEKEND EDITION, from NPR News. I'm Rachel Martin. Public health experts公共衛生專家 have been anxiously watching China over the past couple weeks. A new flu viru禽流感s there has infected感染 dozens of people over a wide area around Shanghai. Most recently, a 7-year-old in Beijing contracted罹患/得病 the virus. NPR's Richard Knox says flu researchers are trying to figure out what sort of threat威脅 this virus poses.(to pose a threat to…對…造成威脅)

RICHARD KNOX, BYLINE: Last Thursday, a precious package arrived at the Centers for Disease Control and Prevention美國疾病控制與預防中心 in Atlanta. Inside, packed in dry ice乾冰 to keep it frozen, was a vial小玻璃瓶 of viruses taken from a 35-year-old Chinese housewife who died last Tuesday. The package was addressed to the CDC's top flu virologist病毒學家, Nancy Cox.

NANCY COX: Once we got the virus, we took it immediately to the appropriate level of biocontainment生物防護等級.

KNOX: That's a so-called Biosafety-3 lab生物安全等級三實驗室, where researchers can keep this dangerous virus under tight control進行嚴密控管.

COX: We unpacked it from the various levels of protection - that is, containers in which it is placed in order to ensure that it doesn't spill散布出去. And then the work actually began.

KNOX: There's a lot of urgent work to do, according to scientists in far-flung遙遠的 labs who also got samples of the virus at the end of last week. In London, virologist John McCauley wants to develop a reliable test可靠度高的測試 to see who's been infected with H7N9, as this virus is called.

JOHN MCCAULEY: The top priority首要任務 is diagnosis診斷(複數為diagnoses) - capability of the global networkm全球系統 to be able to pick up診斷出/辨識出 this virus should it emerge outside of China.

KNOX: At St. Jude's Research Hospital in Memphis, flu researcher Richard Webby is getting started on a vaccine疫苗.

RICHARD WEBBY: We'll start preparing some vaccine seed strains against it, you know, just in case.

KNOX: Having a seed strain疫苗株(病毒株英文為virus strain) is the first step in making a vaccine. CDC scientists have a long list of projects. Cox plans to infect ferrets雪貂(白鼬鼠), weasel-like mammals類似鼬鼠的哺乳類動物 considered close to humans接近人類 in the way they respond to 對…所產生的反應flu viruses. She especially wants to see if ferrets can pass this virus on傳播/傳染 to other ferrets.

COX: We are very eager to do the transmission studies傳染研究 in ferrets. We're very keen to非常熱衷 develop antiserum抗血清 to this virus.

KNOX: Having an antiserum will enable scientists to tell if people close to the known cases in China have been infected without getting seriously ill. There are many mysteries to solve. One of the most puzzling令人感到困惑的 things is how H7N9 has infected people in such a broad area一個非常廣泛的區域of southeast China. Poultry 家禽and wild birds are currently the only known source of infection是唯一確知的感染源. But last week the Chinese reported only 14 infected birds in five different markets. Epidemiologist 流行病學家Marc-Alain Widdowson is in charge of tracking負責追蹤 the infections at the CDC.

MARC-ALAIN WIDDOWSON: It does look as if the infected poultry have dispersed throughout散布遍及 this large area of roughly 400 miles by 400 miles. And it's likely, I think, that there will be more cases in adjacent provinces鄰近的省份 in the weeks to come.

KNOX: Cases of H7N9 have been increasing at a faster pace以快速的方式增加 than cases of another deadly致命的 bird flu virus called H5N1, which researchers have been watching for more than 10 years. But Widdowson says cases of this new virus may soon go up even more because the Chinese have begun testing people for it nationally. So far, he's reassured that monitoring監控 of nearly 800 close contacts密切接觸 of H7N9 cases hasn't turned up firm evidence鐵證 that this virus can be spread easily. But that doesn't mean it won't happen. Nancy Cox notes the virus already has two genetic changes基因改變 that enable it to infect human cells and reproduce複製/繁殖 at humans' body temperature.

COX: Which means that these viruses may already be partially adapted部分適應 - not totally adapted完全適應 but partially adapted - towards the type of virus that might efficiently transmit from human to human.

KNOX: She says the coming weeks may tell whether H7N9 is only a bird disease that occasionally spills over into傳染給 humans, the potential seed of a dangerous global flu pandemic潛在的全球性危險傳染病 or something in between.

Richard Knox, NPR News.

H與N所代表的意義 

(此文轉載至黃瑽寧醫師專欄)

每次一講到人流感，禽流感，就不免有個什麼H和N，很多人經過這麼多次媒體轟炸，還是不清楚是在H什麼N什麼，今天就讓我用比喻的方式，給大家一點概念。

從前有個老偷兒很厲害，常常入侵民宅，什麼門鎖都擋不住他，如入無人之地。老偷兒最厲害的絕活，就是獨自研發出16把萬用鑰匙；因為擁有這16把鑰匙，他可以解開各式各樣的門鎖，也就理所當然地可以大搖大擺，進入任何人家中偷東西了。

但是老偷兒很賊，很怕別人搶了他飯碗，所以他把每支萬用鑰匙編了號，從H1編到H16，每次收徒弟，一律只打一種編號的鑰匙給學生。這些後生晚輩偷兒學成出師，卻因為只拿到其中一種標號的鑰匙，結果只能打開某一類型的門鎖；比如說拿到H1的鑰匙，就只能打開擁有這種鎖的房子。

村莊裡的人很厲害，發現老偷兒什麼鎖都會開，決定發明另一種鎖，就是進門和出門，要用不同的鑰匙打開。這下又多了一道障礙，因為小偷進到屋內偷東西，偷完之後門打不開，出不了門，只能在屋裡等著被警察抓，這也不是辦法。老偷兒摸索了一陣子之後，又另外發明出9支「出門專用」的萬用鑰匙，這下誰也難不倒他了。即便如此，老偷兒還是不肯傾囊相授，他把出門專用的鑰匙也編號N1到N9，每位徒兒只能得到一把。

有一天，老偷兒突然死了，徒子徒孫們繼承了他的行竊事業，卻再也沒有一位小偷能像師父一樣無往不利，因為他們只有兩把鑰匙，一把是進門的H，一把是出門的N，能偷的家庭都很有限。

故事裡的這些小偷，就是在比喻A型流感病毒。A型流感病毒一定帶有兩把鑰匙，這兩把鑰匙各自有編號H1~16，以及N1~9，比如說曾經大流行的H1N1，抑或是今天我們要討論的H7N9，都是這樣分類的。如今大家應該知道H和N是做什麼的了：H是入侵動物呼吸道細胞時所需要的鑰匙（進門使用），而N則是病毒在細胞裡繁殖搞破壞之後，要離開細胞去繼續感染更多人的鑰匙（出門使用）。

感染人類卻只進不出 

然而，在某個月黑風高的夜晚，有一支編號H7的鑰匙摔到地上缺了一角。沒想到這一摔竟然歪打正著，不小心打開了平常開不了的門，進入了平常無法入侵的動物，也就莫名其妙地造成了感染。今天我們討論的H7N9禽流感病毒，一般只會感染鳥類，但H7蛋白在經過小小的突變之後，竟然打開了平常並不熟悉的門（人類的呼吸道上皮細胞），造成好幾例人類的感染。

但是先別擔心太早，因為病毒雖然進了屋子裡搞破壞，卻沒有鑰匙可以出門，也是白搭。H7N9禽流感病毒所擁有出門的鑰匙N9，並不是我們人類細胞所熟悉的編號，所以理論上這些病毒進入細胞後，會被困在細胞裡出不來，導致無法大量繁殖。這可以解釋為什麼目前H7N9禽流感，依然沒有「人傳人」的個案產生。

所以要被H7N9禽流感感染，必須的條件是：必須接觸到帶有這隻病毒的鳥，鴿子，雞，鴨等等活禽，甚至可能要「大量暴露」，才有可能得到。而且就算你身邊的人中標了，也很難傳染給你，因為病毒在他身體裡出不來，就自爆了。

找不到原宿主

目前公共衛生專家遇到最大的困難是，帶有這隻病毒的兇手到底是哪種動物？是雞？是鴨？還是鴿子？根據過去面對其他禽流感的經驗法則，哪裡有鳥死了，病毒應該就在那裡。然而這次人類都死了8位，卻仍未發現有禽鳥類大量死亡的新聞，顯然這隻H7N9病毒對於禽鳥類而言，可能就像小感冒一樣輕輕鬆鬆，死不了的。這樣更令監測的機構提心吊膽，因為兇手躲在哪裡，我們到現在還不清楚。

根據目前受H7N9感染的個案職業別，已知的有豬肉攤販，活家禽宰殺工作者，廚師，農民等等，其他大部分是退休老人，以及一位四歲男童。這些人的共通點，就是可能會出現在傳統市場，接觸到活的雞鴨等家禽。所以大膽的猜測，H7N9病毒，應該是躲在安徽江蘇一帶，菜市場的家禽類身上；當然中國的衛生當局也這麼認為，所以已經開始撲殺一些看似健康的活禽，以及暫停市場上的活禽交易。

因此我想目前還不是台灣同胞緊張焦慮的時候，也許北韓與核四的健康危害還更勝於H7N9。如今我們只需要仰賴檢疫單位，防堵中國坐船來的雞鴨鳥禽，並且如果必須在上海，安徽，江蘇，浙江省經商旅遊時，不要逛傳統活禽市場，以及不要摸或吃未煮熟的禽類，就可以了。至於這隻病毒會不會再進化，需不需要趕快製造疫苗等等問題，留給主政者傷腦筋就好，我個人倒是沒有這麼悲觀。