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 20 個美國人被診斷患豬流感之時，美國疾病控制中心（CDC）的官員們說，他們擔心在美國發生死亡，因為他們預料會出現更多的這種病毒的病例。

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

    今天早些時候，美國國土安全部秘書珍妮 納波利塔諾說，政府宣布了突發公共衛生事件，這將使得政府能夠騰出資源財力來解決這個問題。

    在白宮舉行的新聞發布會上，疾病控制和預防中心的代理主任理查德 貝瑟博士向美國人保證，政府正在采取積極的步驟控制疫情爆發，但是可能預計在不久的將來會出現更多的情況。

    “流感病毒是非常難以預測的。傳染病的爆發是非常難以預測的，”貝瑟說。“我們考慮這更象是一場馬拉松。我們認為它將繼續蔓延，但是我們正在采取積極的行動。 ”

    還沒有用于這種具有豬、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，他們已經加大了全國各地的醫療監察，并且作為緊急聲明的一部分，騰出州政府和聯邦政府的資源用于預防。官員們還強調了個人護理和良好保健習慣的重要性。