Like seasonal flu, swine flu in humans can vary in severity from mild to severe.

与季节性流感一样，人感染猪流感的严重程度也各有不同，从轻微到严重不等。

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"Immunologically this is acting like seasonal flu and we are very pleased with that, " said Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases.

“从免疫学上看，这样的行为象季节性流感，并且我们对此很满意，”美国国家过敏症和传染病协会的主任安东尼福奇博士说。“

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Fortunately, the swine flu that we're seeing still is a moderate disease that is behaving very much like ordinary seasonal influenza.

幸运的是，令人关注的猪流感病毒目前仍很温和，它与普通的季节性流感十分相似。

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W.H.O.special adviser Keiji Fukuda reported earlier this month that the virus has acted in some ways like seasonal flu.

VOA: special.2009.11.24

W.H.O.special adviser Keiji Fukuda said last week that the virus has continued to act in some ways like seasonal flu.

VOA: special.2009.11.11

It appears to be acting like a typical seasonal flu, only it's out of season.

CNN: 2 U.S. swine flu dead had other health problems, officials say

Levels of flu-like illness were said to be "within the usual seasonal activity range" but were "higher than Wales has experienced in recent years".

BBC: GPs report small rise in number of flu patients