"流感大军"兵临城下

资料:自1580年有记载以来,世界范围内的流感流行或大流行已经超过30次,其中最大规模的流行发生于1918年至1919年,即著名的"西班牙流感",该次流感中死亡2100万人,超过一次世界大战死亡人数。最近的流感大流行分别发生在1957、1968和1977年。 我国是流感多发区,流感的流行或局部爆发基本上每年都会发生。每年有一亿多人遭受流感困扰,因流感到医院就医者超过50万人。为此,国家、单位和个人付出了巨额医疗费,并造成工作、学习上的严重损失。     

流感：大流行没想象中那么可怕

在人类发展史上，分别在1918年、1957年、1968年和1977年出现过4次流感大流行．2009年发生了新甲型H1M流感流行。这几次流感（大）流行的主要原因是甲型流感病毒发生抗原变异，人群普遍没有免疫力．再加上其传播范围广速度快造成短时间内世界多个国家发生流感流行。     

新型流感病毒出现和流感大流行

20世纪出现了3次流感大流行,分别由A型流感病毒H1N1、H2N2和H3N2三种不同的抗原亚型引起,其中1957年和1968年的两次流行发生在现代病毒学时代,流感病毒的特征得到了系统的研究。流感流行事件表明流感大流行在时间和形式上是不可预测的。有证据显示流感大流行主要是由人流感病毒与动物A型流感病毒的基因重排而产生新血凝素亚型的病毒引起。     

流感/禽流感病毒血凝素的分子遗传特征与其致病性

流感病毒是引起流行性感冒的病原，分为甲、乙、丙三型，其中以甲型流感对人类威胁最大。自1918年的流感大流行夺走约4千万人生命以来，在1957年和1968年相继又发生了世界大流行。这三次大流行都是由于流感病毒变异出现新亚型而引起，即H1N1（1918），H2N2（1957），H3N2（1968）流感病毒新亚型。1997年香港18人感染禽流感H5N1亚型。6人死亡，首次突破人种属屏障，随着人感染禽流感病例的增多，发病地域扩大。引起了全球的担忧，     

禽流感对人类的危害和防治措施

禽流感(avian/bird influenza)于1878年首先在意大利被陈述爆发,此后禽流感病毒不断地侵袭着整个世界,已有10余次大流行。特别是从上世纪90年代后期起,禽流感在欧亚大陆的爆发日趋频繁。人流感于1658年首先在意大利威尼斯被陈述爆发,造成6万人死亡,当时认为是上帝的惩罚,命名为influenza(魔鬼)。20世纪已经发生5次世界性流行。1918~1919年的流感大流行导致5亿人发病,2000万~4000万人死亡。1957年大流行死亡100万人,1968年死亡75万人,1977年死亡人数不祥。今年5月6日到8日,青海湖国家级自然保护区管理局巡查人员在鸟岛及其周边地区又发现28只…     

流感大流行与应对策略分析

20世纪人类发生了三次全球性流感大流行,即1918年西班牙型流感（H1N1亚型）、1957年亚洲型流感（H2N2亚型）和1968年香港型流感（H3N2亚型）.其中第一次流感大流行,在短短的6-9个月时间内席卷了全球,全世界有20%的人口--4亿人感染,死亡4千万至5千万,超过了第一次世界大战的死亡人数,成为人类传染病史上最大的灾难.目前,全世界正面临着禽流感大流行的威胁,人们更关心是否有可能由此引发席卷全球的人类流感大流行.     

流感病毒及相关疫苗的研究概况

流行性感冒是由流感病毒（influenza virus），引起的一种人、禽、畜共患的急性呼吸道传染病。1918年至今人类遭受的4次流感大流行：1918年“西班牙流感（H1N1型）”，1957年“亚洲流感（H2N2型）”，1968年“香港流感（H3N2型）”以及1977年“俄罗斯流感（H1N1型）”使许多人丧失了生命。每年全球范围内的流行性感冒都会使得许多人死亡，其中感染率和死亡率最高的是〉65岁的老人，〈2岁的儿童以及在流感病毒猖獗发生地区从事医疗卫生工作的人员。     

江苏省自然人群中甲1型流感病毒感染的血清流行病学研究

20世纪以来,全球四次流感大流行有两次是由甲1型流感病毒引起。第一次世界大流行发生在1918年～1919年,是由西班牙流感病毒H1N1引起的,估计全世界患病人数在5亿以上,发病率20％～40％,死亡人数2000～5000万,之后该病毒在人群中存在并流行。到1957年发生第二次流感（H2N2）大流行后,H1N1在人群中一度消失。直到1977年5月H1N1亚型再次在我国丹东、鞍山和天津等地出现,并与H3N2和B型毒株并存,但未引起大流行。本研究对江苏省部分人群甲1型流感抗体水平进行检测和分析,以期获得血清流行病学基础资料,了解群体免疫水平。     

中国应对流感大流行的对策分析

上世纪全球发生了3次世界流感大流行:1918西班牙型流感(H1N1亚型);1957亚洲型流感(H2N2亚型);1968香港型流感(H3N2亚型);其中第一次流感大流行,在6~9个月的时间内席卷了全球,全世界有20%的人口———4亿人感染,死亡4 000万~5 000万,对全世界的经济、社会活动造成了毁灭性的影响,成为人类传染病史上最大的灾难。美国对该次流行的危害做了进一步统计,短短的3个星期传遍全国,使美国1918年10月份的死亡率比平时增长了10倍以上,当年美国人的期望寿命下降了13岁。根据经验,世界性的流感大流行每30~40年发生一次,现在距离上次流行已经有35年的时…     

威胁健康的瘟神——流感

把梳感比做瘟神,是不是有些危言耸听呢?看一下流感的历史和现状,就会觉得流感确是一个尚未被征服的人间瘟神。 据有文字可查的资料记载.1580年的大流行,使马德里变成荒无人烟的地方,意大利、西班牙竖起了几十万座新墓碑。进入19世纪以来,流感更加猖狂地向人类进攻,几乎每隔几年或十几年就要周期性地发生一次世界性大流行,其中1889年至1890年的流感大流行,波及范围特别广泛,几乎绕地球一周,使全世界的一半人口得病。1918～1920年的流感人流行,约有5亿5千万人得了流感,光病死者达2000万人,比第一次世界大战各国死亡人数的总和还要多。1957年流感大流行。仪短短半年时间,就传遍了全世界,患者达10亿以上。最近的一次流感大流行,发生在1968年,这次流行侵袭了55个国家和地区,大部分国家的     

Influenza pandemics of the 20th century

Three worldwide (pandemic) outbreaks of influenza occurred in the 20th century: in 1918, 1957, and 1968. The latter 2 were in the era of modern virology and most thoroughly characterized. All 3 have been informally identified by their presumed sites of origin as Spanish, Asian, and Hong Kong influenza, respectively. They are now known to represent 3 different antigenic subtypes of influenza A virus: H1N1, H2N2, and H3N2, respectively. Not classified as true pandemics are 3 notable epidemics: a pseudopandemic in 1947 with low death rates, an epidemic in 1977 that was a pandemic in children, and an abortive epidemic of swine influenza in 1976 that was feared to have pandemic potential. Major influenza epidemics show no predictable periodicity or pattern, and all differ from one another. Evidence suggests that true pandemics with changes in hemagglutinin subtypes arise from genetic reassortment with animal influenza A viruses.     

Emergence of new viruses in Asia: is climate change involved?

Tropical Africa is not the only area where deadly viruses have recently emerged. In South-East Asia severe epidemics of dengue hemorrhagic fever started in 1954 and flu pandemics have originated from China such as the Asian flu (H2N2) in 1957, the Hong-Kong flu (H3N2) in 1968, and the Russian flu (H1N1) in 1977. However, it is especially during the last ten years that very dangerous viruses for mankind have repeatedly developed in Asia, with the occurrence of Alkhurma hemorrhagic fever in Saudi Arabia (1995), avian flu (H5N1) in Hong-Kong (1997), Nipah virus encephalitis in Malaysia (1998,) and, above all, the SARS pandemic fever from Southern China (2002). The evolution of these viral diseases was probably not directly affected by climate change. In fact, their emergential success may be better explained by the development of large industry poultry flocks increasing the risks of epizootics, dietary habits, economic and demographic constraints, and negligence in the surveillance and reporting of the first cases.     

Influenza pandemic planning

Periodically, novel influenza viruses emerge and spread rapidly through susceptible populations, resulting in worldwide epidemics or pandemics. Three pandemics occurred in the 20th century. The first and most devastating of these, the "Spanish Flu" (A/H1N1) pandemic of 1918-1919, is estimated to have resulted in 20-50 million or more deaths worldwide, with unusually high mortality among young adults [C.W. Potter, Chronicle of influenza pandemics, in: K.G. Nicholson, R.G. Webster, A.J. Hay (Eds.), Textbook of Influenza, Blackwell Science, Oxford, 1998, p. 3]. Mortality associated with the 1957 "Asian Flu" (A/H2N2) and the 1968 "Hong Kong Flu" (A/H3N2) pandemics was less severe, with the highest excess mortality in the elderly and persons with chronic diseases [J. Infect. Dis. 178 (1998) 53]. However, considerable morbidity, social disruption and economic loss occurred during both of these pandemics [J. Infect. Dis. 176 (Suppl. 1) (1997) S4]. It is reasonable to assume that future influenza pandemics will occur, given historical evidence and current understanding of the biology, ecology, and epidemiology of influenza. Influenza viruses are impossible to eradicate, as there is a large reservoir of all subtypes of influenza A viruses in wild aquatic birds. In agricultural-based communities with high human population density such as are found in China, conditions exist for the emergence and spread of pandemic viruses. It is also impossible to predict when the next pandemic will occur. Moreover, the severity of illness is also unpredictable, so contingency plans must be put in place now during the inter-pandemic period. These plans must be flexible enough to respond to different levels of disease.     

The importance of animal influenza for human disease

Influenza is a zoonotic disease caused by a constantly varying RNA virus resulting in a need for continuous surveillance to update human vaccines. Our knowledge indicates that the intermittent pandemics of influenza originate from influenza viruses or gene segments from influenza viruses in lower animals and birds. These pandemics can be mild to catastrophic. While we have learned a great deal about the ecology and molecular properties of "animal" influenza viruses, we do not have a system for comprehensive international surveillance. The 1918 Spanish influenza pandemic that originated from lower animals and the recent H5N1 bird flu incident in Hong Kong serves to remind us that influenza is an emerging disease. The challenge for the 21st century is to accumulate the necessary epidemiological data on animal influenza viruses so that an international surveillance system can be devised. This epidemiological data may provide clues on how to reduce interspecies transmission of influenza. The separation of aquatic birds from other "land based" domestic poultry in Hong Kong after the H5N1 bird flu incident indicates that animal husbandry practices could influence the interspecies transmission of influenza viruses.     

A comparison of monovalent Hong Kong influenza virus vaccine with vaccines containing only pre-1968 Asian strains in adult volunteers: A report to the Medical Research Council Committee on Influenza and other Respiratory Virus Vaccines*

A total of 1601 adult industrial workers were vaccinated with either monovalent inactivated vaccine of the Hong Kong strain of influenza A virus, or with polyvalent vaccine containing only pre-1968 Asian viruses. Serological investigations on a random sample of volunteers showed that 53/56 (95%) given Hong Kong vaccine developed a significant rise in specific haemagglutination-inhibiting antibody; final titres were 1/48 or greater in 39 (70%) and the GMT (geometric mean titre) was 96·5. After polyvalent Asian vaccine, 40/67 (60%) also produced antibody against Hong Kong virus, but only 21 (31%) had final titres of 1/48 or above, and the GMT rose only to 14·1. An intranasal spray of the Hong Kong vaccine in addition to injected Asian vaccine gave no additional increase in antibody.     

Influenza A virus recycling revisited

Current textbooks link influenza pandemics to influenza A virus subtypes H2 (1889-91), H3 (1990), H1 (1918-20), H2 (1957-58) and H3 (1968), a pattern suggesting subtype recycling in humans. Since H1 reappeared in 1977, whatever its origin, some workers feel that H2 is the next pandemic candidate. This report reviews the publications on which the concept of influenza A virus subtype recycling is based and concludes that the data are inconsistent with the purported sequence of events. The three influenza pandemics prior to 1957-58 were linked with subtypes through retrospective studies of sera from the elderly, or through seroarchaeology. The pandemic seroarchaeological model for subtype H1 has been validated by the recent recovery of swine virus RNA fragments from persons who died from influenza in 1918. Application of the model to pre-existing H3 antibody among the elderly links the H3 subtype to the pandemic of 1889-91, not that of 1900 as popularly quoted. Application of the model to pre-existing H2 antibody among the elderly fails to confirm that this subtype caused a pandemic in the late 1800's, a finding which is consistent with age-related excess mortality patterns during the pandemics of 1957 (H2) and 1968 (H3). H2 variants should be included in pandemic planning for a number of reasons, but not because of evidence of recycling. It is not known when the next pandemic will occur or which of the 15 (or more) haemagglutinin subtypes will be involved. Effective global surveillance remains the key to influenza preparedness.     

Pandemic Influenza Planning,United States, 1978–2008

During the past century, 4 influenza pandemics occurred. After the emergence of a novel influenza virus of swine origin in 1976, national, state, and local US public health authorities began planning efforts to respond to future pandemics. Several events have since stimulated progress in public health emergency planning: the 1997 avian influenza A(H5N1) outbreak in Hong Kong, China; the 2001 anthrax attacks in the United States; the 2003 outbreak of severe acute respiratory syndrome; and the 2003 reemergence of influenza A(H5N1) virus infection in humans. We outline the evolution of US pandemic planning since the late 1970s, summarize planning accomplishments, and explain their ongoing importance. The public health community’s response to the 2009 influenza A(H1N1)pdm09 pandemic demonstrated the value of planning and provided insights into improving future plans and response efforts. Preparedness planning will enhance the collective, multilevel response to future public health crises.     

Influenza--its impact and control.

Influenza is an underestimated public health problem. Epidemics spread rapidly from country to country and may affect as many as 500 million people across the world in a moderate influenza year. The disease, particularly influenza A, kills and the new influenza viruses which appeared in 1957 (Asian influenza) and 1968 (Hong Kong) are estimated to have caused at least 100,000 deaths in the United States of America. Deaths from influenza also occur in years when there is no new virus; at least 10,000 excess deaths have been documented in the United States during each of 18 different epidemics recorded from 1957 to 1985. Although most deaths are among the elderly, influenza occurs in all age groups with repercussions in schools and work places, and on hospital resources, at a high cost to society. As many as 79-80% of influenza cases can be prevented when the virus inducing the outbreak and the virus used in the influenza vaccine are closely related. Preventing 80% of cases would correspond in the United States to a saving of US $2.5 billion. People at the greatest risk of influenza-related complications are adults and children with chronic disorders of the pulmonary or cardiovascular systems, residents of nursing homes and of facilities for patients with chronic medical conditions. Other priority groups for vaccination are those at moderate risk of influenza-related complications such as healthy elderly persons, people with chronic metabolic diseases, children and teenagers on long-term aspirin therapy. Groups potentially capable of transmitting influenza to high-risk persons should also be vaccinated.(ABSTRACT TRUNCATED AT 250 WORDS)     

Influenza A (H5N1) in Hong Kong: an overview

Worldwide pandemics of human influenza virus caused extensive morbidity and mortality around the world had been documented in the 20th century. However, the mechanisms involved in the emergence of novel influenza virus and the epidemiological factors leading to pandemics are unpredictable. Southern China is postulated as the epicentre of influenza epidemics due to its agricultural-based communities and high population density. Pandemic influenza viruses are through to arise from avian viruses through genetic reassortment among influenza viruses. An influenza virus (H5N1) known to infect only birds previously was found to infect human causing disease and death in Hong Knog in 1997 and the outbreak involved 18 patients with six deaths. Prior to the human outbreak, the H5N1 virus was found to cause extensive death in chickens in three farms in Hong Kong. The significance of this outbreak raised worldwide concern on the possibilities that such an influenza virus may become the next influenza pandemic strain. Investigations were initiated to find the source of the virus. In addition the extend of spread in individuals in contact with the index case and infected poultry was studied by H5-specific serology. Results demonstrated that individuals in close contact with the index case or with exposure to poultry were at risk of being infected. Out of the 18 cases of human infection, eleven had severe infection with symptoms of pneumonia and multi-organ failure. All severe cases presented with lower respiratory infection and lymphopenia and six eventually died. Case-fatality ratio was high among patients over 12 years of age (five out of nine). Control measures aimed at reducing exposure of human to potential H5-positive poultry were instituted which included culling of all poultry in Hong Kong, the segregation of water fowls and chicken, and the introduction of import control measures for chickens. Such measures had successfully controlled the outbreak and continuous surveillance of the poultry in Hong Kong of H5N1 infection is maintained to minimize future human exposure.     

1951 influenza epidemic, England and Wales, Canada, and the United States

Influenza poses a continuing public health threat in epidemic and pandemic seasons. The 1951 influenza epidemic (A/H1N1) caused an unusually high death toll in England; in particular, weekly deaths in Liverpool even surpassed those of the 1918 pandemic. We further quantified the death rate of the 1951 epidemic in 3 countries. In England and Canada, we found that excess death rates from pneumonia and influenza and all causes were substantially higher for the 1951 epidemic than for the 1957 and 1968 pandemics (by > or =50%). The age-specific pattern of deaths in 1951 was consistent with that of other interpandemic seasons; no age shift to younger age groups, reminiscent of pandemics, occurred in the death rate. In contrast to England and Canada, the 1951 epidemic was not particularly severe in the United States. Why this epidemic was so severe in some areas but not others remains unknown and highlights major gaps in our understanding of interpandemic influenza.