Analyses of infection rates in modern seasonal flu epidemics suggest that with age comes a subtle buildup of immunity to flu viruses in general.
近年来对季节性流感流行的感染率分析表明，一般而言，随着年龄的增长，针对流感病毒的免疫力也在日积月累地加强。
Pregnant women face an increased risk even during outbreaks of seasonal influenza. But the new H1N1 flu has been affecting a younger age group than seasonal flu epidemics.
即使在季节性流感爆发的时，孕妇面临的风险就已经增加了。但是，新出现的。
If only we could develop a vaccine that was effective against all strains of flu, we might prevent both annual epidemics and occasional pandemics like the one now under way.
如果我们能研制一种对所有流感病毒株都有效的疫苗，我们就可以预防年度季节性流感及偶见的流感大流行，就像其它那些疾病一样。
As model epidemics they chose those of 1918 (the famous “Spanish” flu that is reckoned to have killed 50m-100m) and 1957 (less lethal, but still pretty nasty).
他们选择了历史上两次大流感作为流感模型，其一是1918年著名的西班牙大流感，死亡人数达五千万至一亿，其二是1957年的流感，杀伤力较前者虽不大，但同样不堪回首。
Epidemics like SARS in 2003, sporadic outbreaks of the H5N1 flu since 1997, and the H1N1 flu pandemic of 2009 racked up enormous economic costs around the world.
诸如2003年爆发的非典疫情、1997年以来禽流感的零星爆发以及2009年甲流大流行，给全世界造成了巨大经济损失。
Nearly half the world's people are crowded into urban areas, often without adequate sanitation, and are exposed to epidemics of such diseases as measles and flu.
近一半的世界人口拥挤在城市，经常没有足够的卫生设施，暴露于诸如麻疹和流感这类疾病的流行。
In the effort to control influenza epidemics, scientists try to identify, as quickly as possible, new flu viruses.
为了努力控制流行感冒，科学家试图尽快识别新的流感病毒。
Epidemics such as swine flu, bird flu, and SARS are spread via close contact with others who are infected.
流行性传染病，如猪流感、禽流感和SARS，通过与感染者密切接触而传播。
Epidemics such as swine flu, bird flu, and SARS are spread via close contact with others who are infected.
流行性传染病，如猪流感、禽流感和SARS，通过与感染者密切接触而传播。
应用推荐