世卫组织40年来第一次把传染病警戒级别升至最高级别，目前有74个国家，数万人感染甲流病毒。世卫组织于周四宣布了这一决议。

　　The swine flu crisis has escalated into the world's first influenza pandemic in 40 years, the World Health Organization declared Thursday, after infecting tens of thousands of people in 74 countries。

　　WHO director general Margaret Chan said the declaration of a "moderate" pandemic should not be a cause for panic and did not mean the death toll from A(H1N1)， which currently stands at less than 150, would sharply increase。

　　The UN body said it was neither recommending the closure of borders nor restrictions in movement of people, goods and services in the wake of its declaration。

　　However it was now clear the virus was spreading among communities beyond outside the Americas where it was first detected in April and the world must guard against complacency。

　　"We will be raising our pandemic alert level to level six; and this means that the world is moving into the early days of its first influenza pandemic in the 21st century," Chan told reporters after a meeting of scientific experts to discuss the virus and its spread。

　　"At this time, the global assessment is that we are seeing a moderate pandemic," she added。

　　The WHO raised its six-phase alert level to five at the end of April, indicating that a pandemic is imminent, and officials said earlier this week that a decision to move up to the maximum level was "very, very close"。

　　The latest figures from the organisation show that the number of reported A(H1N1) infections has reached 27,737 in 74 countries, including 141 deaths。

　　The vast majority of the deaths have been in Mexico, the original epicentre of the outbreak, and no deaths have been announced outside the Americas。

　　"Moving to pandemic phase six level does not imply we will see increase in number of deaths or very severe cases," said Chan。

　　"Quite on the contrary, many people having mild disease will recover without medicine in some cases, and it is good news, but the tendency to move into complacency is our biggest concern because we need to continue to monitor this virus, follow its track and do not allow it to come back in the second wave to give us more trouble."

　　Chan said the health agency is concerned that the virus is causing "very severe disease disproportionately" among people 30 to 50 years old。

　　"These are people who were previously healthy and they suffer severe disease and also many of them die," she said。

　　The declaration comes amid growing evidence that the virus, which originated in Mexico two months ago, is now being widely transmitted between humans in Asia and Europe as well as the Americas。

　　Hong Kong authorities Thursday ordered all primary schools in the city to be closed for two weeks after the first cluster of local swine flu cases was found in the Chinese territory。

　　Meanwhile in Germany, a school for Japanese youngsters in the western city of Duesseldorf was closed after 27 children tested positive for the virus。

　　And in Australia, four swine flu victims were admitted to intensive care wards Thursday。

　　Following the announcement, the Red Cross and Red Crescent societies were mobilising to respond to the pandemic。

　　"Red Cross and Red Crescent societies all over the world must be mobilised and ready to respond to the crisis and implement their role as auxiliaries to their governments," said Dominique Praplan, head of the International Federation of Red Cross and Red Crescent Societies' health and care department。

　　Chan said that it was up to individual countries to decide how to proceed given the outbreak was now classified as a pandemic。

　　"The global level assessment is very different from national level assessment because it has to take into account the vulnerability of the population in a specific country and also the health system resilience," she said。

　　Although no vaccine against A(H1N1) has yet to be produced, drug companies are looking to come up with one by the end of June or early July and last month sent three "seed viruses" to drug companies for use in making a vaccine。

　　Chan said the WHO would ask drug-makers to quickly prepare to produce swine flu vaccines once the production of seasonal flu shots ends in the next couple of weeks。

　　The last flu pandemic came after an outbreak of the H3N2 viral strain from 1968-69, which originated in Hong Kong, and went on to kill up to two million people。

　　相关中文报道：

　　世界卫生组织总干事陈冯富珍11日正式宣布把甲型H1N1流感警戒级别升至6级，这意味着世卫组织认为疫情已经发展为全球性"流感大流行"。

　　陈冯富珍是在征询世卫组织专家委员会的意见后，做出把流感大流行警戒级别提升至6级的决定的。她在当天专家委员会会议结束后举行的新闻发布会上说，这是"非常重要同时也是非常具有挑战性"的一天，因为宣布6级警戒意味着21世纪的首次"流感大流行"已经到来。

　　按照世卫组织目前的流感警戒规定，当病毒在其认定的两个不同地区(如北美洲和大洋洲)出现群体性传播时，警戒级别就应升至6级。陈冯富珍表示，目前除墨西哥和美国外，澳大利亚、英国、西班牙、日本和智利都确认其境内出现了一定程度的群体性传播。

　　陈冯富珍重申，"流感大流行"主要反映的是病毒的地理扩散范围，而不是流感疾病本身的严重程度。宣布"流感大流行"并不一定意味着疾病的严重程度或致死率有了显著提高。她说，实际上目前许多患者病情较轻，而且不用服药即可自愈。根据专家评估，这次"流感大流行"的严重程度为中等或一般水平。

　　根据世卫组织规定，流感大流行警戒级别共分6级。

　　1级：在自然界中，流感病毒长期在动物尤其是鸟类中传播，但从未有此类病毒导致人类感染的报告，即便从理论上讲它们有可能进化为可引发人类流感大流行的病毒。

　　2级：在家养或野生动物间流行的已知的动物流感病毒导致了人类感染，被视为有流感大流行的潜在威胁。

　　3级：某种动物流感病毒或动物流感病毒和人类流感病毒重组后的病毒，已经在人群中造成零星或小规模传染，但尚未出现足以导致人际间大流行的传播能力。

　　4级：某种动物流感病毒或动物流感病毒和人类流感病毒重组后的病毒，已经证实可在人际间传播，并在社区层面暴发，这是流感大流行风险增大的重要节点，但并不意味着流感大流行肯定会出现。

　　5级：某种流感病毒在同一地区至少两个国家的人际间传播。尽管在这一级别，其他大多数国家仍未受影响，但它是一个重要信号，表明流感大流行"正在逼近"。

　　6级：某种流感病毒在疫情发源地以外其他地区的至少一个国家发生了社区层面的暴发，表明病毒正在全球蔓延，这也是流感大流行级。

　　从概念上讲，流感大流行指的是流感病毒的影响范围，而不是病毒的严重程度和死亡人数。世卫组织官员和专家近日多次强调，流感大流行6级警告的含义主要是指病毒的持续人际间传播范围超出北美，已在其他地区许多国家发生疫情，而与疫情本身的严重程度无关。