2009年3月暴发于北美的甲型H1N1流感,并未如当初预料般,在北半球炎热的夏季来临时停下蔓延的脚步,相反,越来越多的国家和地区变成流感疫区,多个国家和地区陆续进入社区暴发阶段。步入冬季的南半球尤其是南美洲国家,疫情蔓延迅速。 Influenza A (H1N1) outbreak in North America in March 2009 was not as expected. As the hot summer in the northern hemisphere came to a halt, the spread of influenza became more frequent. More and more countries and regions became infected with flu One country and one after another into the community outbreak stage. Into the winter in the southern hemisphere, especially in South America, the epidemic spread rapidly.