Amid confirmation that 20 Americans have been diagnosed with the swine flu, officials at the U.S. Centers for Disease Control (CDC) said they fear death in the United States as they expect more cases of the virus to emerge.

    Dr. Anne Schuchat, director of the CDC's National Center for Immunization and Respiratory Diseases, said it is premature to say the disease in the United States is different than the one that has killed about 86 people in Mexico, and how serious this new virus is compared to typical flu viruses remains to be seen. On Sunday, Canada became the third country to confirm human cases of the unique virus.

    Earlier today, Department of Homeland Security Secretary Janet Napolitano said the government declared a public health emergency, which will allow it to free up resources to tackle the issue.

    At a White House press conference, Dr. Richard Besser, acting director of the Centers for Disease Control and Prevention (CDC), ensured Americans that the administration is taking aggressive steps to control the outbreak, but that more cases are likely to expect to emerge in the near future.

    "Flu viruses are very unpredictable. Outbreak of infectious diseases are very unpredicatable," Besser said. "We view this more as a marathon. We think this will continue to spread but we are taking aggresive action."

    There is no vaccination for the swine flu strain, which has elements of pig, bird and human strains. But officials said they have ramped up medical surveillance around the country and as part of the emergency declaration, freed up state and federal resources for prevention. Officials also emphasized the importance of individual care and good hygenic pratices.

    在確認(rèn) 20 個(gè)美國(guó)人被診斷患豬流感之時(shí)，美國(guó)疾病控制中心（CDC）的官員們說(shuō)，他們擔(dān)心在美國(guó)發(fā)生死亡，因?yàn)樗麄冾A(yù)料會(huì)出現(xiàn)更多的這種病毒的病例。

    美國(guó)疾病控制中心的國(guó)家免疫和呼吸系統(tǒng)疾病中心主任安妮 舒卡特博士說(shuō)，說(shuō)在美國(guó)的疾病不同于在墨西哥造成大約 86 人死亡的那種疾病，還言之過(guò)早；而且這種新病毒比較典型的流感病毒是如何的嚴(yán)重，仍有待觀察。星期天，加拿大成為確認(rèn)這種奇特病毒的人類病例的第三個(gè)國(guó)家。

    今天早些時(shí)候，美國(guó)國(guó)土安全部秘書珍妮 納波利塔諾說(shuō)，政府宣布了突發(fā)公共衛(wèi)生事件，這將使得政府能夠騰出資源財(cái)力來(lái)解決這個(gè)問(wèn)題。

    在白宮舉行的新聞發(fā)布會(huì)上，疾病控制和預(yù)防中心的代理主任理查德 貝瑟博士向美國(guó)人保證，政府正在采取積極的步驟控制疫情爆發(fā)，但是可能預(yù)計(jì)在不久的將來(lái)會(huì)出現(xiàn)更多的情況。

    “流感病毒是非常難以預(yù)測(cè)的。傳染病的爆發(fā)是非常難以預(yù)測(cè)的，”貝瑟說(shuō)。“我們考慮這更象是一場(chǎng)馬拉松。我們認(rèn)為它將繼續(xù)蔓延，但是我們正在采取積極的行動(dòng)。 ”

    還沒(méi)有用于這種具有豬、鳥和人的菌株要素的豬流感病毒菌株的接種疫苗。但是官員們表示，他們已經(jīng)加大了全國(guó)各地的醫(yī)療監(jiān)察，并且作為緊急聲明的一部分，騰出州政府和聯(lián)邦政府的資源用于預(yù)防。官員們還強(qiáng)調(diào)了個(gè)人護(hù)理和良好保健習(xí)慣的重要性。