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將近十年嚟，科學家一直喺中國

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最高嘅山同最偏僻嘅山窿

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尋找著一種致命嘅新型病毒

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佢哋最終喺雲南洞穴嘅蝙蝠身上搵到

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呢種未知嘅病毒係一種冠狀病毒

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佢引發咗 2003 年
嚴重急性呼吸綜合征

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即係沙士

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冠狀病毒係一類

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由細小蛋白刺突包裹嘅病毒
佢睇起身好似一個皇冠

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用拉丁語講就係 corona

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已知嘅冠狀病毒有幾百種

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其中有七種會感染人類、令人病

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譬如話，沙士冠狀病毒會引發沙士

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中東呼吸綜合症冠狀病毒
會引發中東呼吸綜合症

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新冠病毒就會引發新冠肺炎

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喺七種人類冠狀病毒之中
四種會引致感冒

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鼻、喉嚨會受到輕度而高傳染性嘅感染

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兩種會感染肺部
並引發更嚴重嘅疾病

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而第七種，即新冠病毒
有頭六種嘅特徵

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佢好容易傳播
嚴重影響肺部功能

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一個病毒感染者一旦咳嗽
含有病毒嘅飛沫就開始散播

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當飛沫入咗鼻或者嘴
病毒就傳染畀另一個人

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當好多人都喺同一個密閉空間嗰時

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冠狀病毒就係傳播得最犀利

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而天氣寒冷，令冠狀病毒
脆弱嘅外殼免於脫水

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令佢哋喺宿主之間生存得更耐

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陽光中嘅紫外線
或者可以破壞脆弱嘅外殼

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雖然季節變化對已知病毒嘅影響大

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但由於冇人對呢種新病毒有免疫

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所以佢唔需要理想條件
就可以感染好多潛在宿主

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喺人體之中，蛋白刺突嵌入
宿主細胞，並同佢結合

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因此，病毒可以綁架
成個宿主細胞機制

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要挾宿主細胞複製病毒嘅基因

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冠狀病毒將佢哋嘅基因儲存喺 RNA

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所有病毒都可以分為 RNA 病毒
或者 DNA 病毒

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RNA 病毒一般都比較細
攜帶較少嘅基因

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即佢哋可以感染好多宿主
仲可以喺宿主體內快速複製

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一般嚟講，RNA 病毒
都係冇校對機制嘅

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而 DNA 病毒就有

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所以當一個 RNA 病毒複製緊

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基因變異就更頻繁噉發生

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呢啲變異好多都係冇用
甚至係有害

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但有啲變異可以令病毒
更加適應到某啲環境

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譬如係一種新嘅宿主物種

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當一種病毒從動物傳播到人類身上
流行病就會發生啦

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引發伊波拉、寨卡、沙士
同埋新冠肺炎嘅 RNA 病毒都係噉

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噉進入人體之後，病毒依然會變異

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雖然唔會通常演變到成為一種新嘅病毒

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但都做到啲基因變異出嚟

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冠狀病毒同大部分 RNA 病毒
有幾個關鍵嘅區別

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佢哋比較大隻
即係有最多基因

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噉就更易令有害變異發生

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為咗降低呢種風險
冠狀病毒有一種獨特嘅特點

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佢含有一種酵素，專門
負責檢查、糾正複製錯誤

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咁就令到冠狀病毒更加穩定

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令到佢比其他 RNA 病毒變異得更慢

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雖然聽起嚟好恐怖

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但係講到要瓦解冠狀病毒

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變異得慢係好事嚟

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因為當我哋感染病菌之後
我哋嘅免疫系統可以識別病菌

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而當我哋再次感染病菌時
就可以更快消滅病菌

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噉佢哋就唔會再搞到我哋病

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但係病毒變異可以令我哋嘅免疫系統
冇咁容易識別到病毒

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噉擊退病毒就會難啲

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而病毒變異會令抗病毒藥物
同疫苗，變得冇咁有效

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因為藥物同疫苗
係專門針對某種病毒嘅

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噉就係點解我哋每年
都要重新打一次流感疫苗

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因為流感病毒變異得好快
新嘅病毒不斷出現

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冠狀病毒較慢嘅變異速率

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意味著我哋嘅免疫系統
同埋藥物、疫苗

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喺感染之後嘅一段長時間
都仲可以識別到呢啲病毒

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噉就可以更好咁保障我哋

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目前，我哋依然都未知我哋嘅身體
可以對唔同嘅冠狀病毒免疫幾耐

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面對任何冠狀病毒，永遠都
唔會有一種肯定嘅療法或疫苗

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雖然科學家開始研發 
針對 SARS 同 MERS 嘅治療

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但我哋都仲未重點研究感冒治療

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喺療法嘅臨床實驗完成之前
疫情就已經結束啦

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有科學家話，鑒於我哋一直喺度
入侵其他動物嘅棲息地

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新嘅冠狀病毒
係無可避免會傳播到人身上

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但如果我哋要探索未知
都唔一定次次要咁大劑嘅