摘要
AFTER its debut in late March, A/H1N1 flu soon spread from Mexico and the U.S. to more than 30 countries and regions worldwide, including China’s mainland and Hong Kong, causing global alarm and prompting a flurry of precautions. By April 27
AFTER its debut in late March, A/H1N1 flu soon spread from Mexico and the .U.S. to more than 30 coun-tries and regions worldwide, including China＇s mainland and Hong Kong, causing global alarm and prompting a flurry of precautions. By April 27 the World Health Organization had raised its pandemic alert level from Phase 3 to 4, and only two days later, to the second place register on the scale.
