Swine influenza: how much of a global threat?

摘要

On April 27, WHO raised its pandemic alert level from phase 3 to phase 4 after human cases of a novel H1N1 swine influenza A virus spread quickly around the world from its origin in Mexico. Concern over the virus-a hybrid of human, pig, and avian influenza-started mounting internationally last week following outbreaks of influenza-like illnesses in Mexico and other countries. As of April 28, according to WHO, Mexico had 26 laboratory confirmed human cases of swine influenza A (H1N1) with seven confirmed deaths. The USA had 40 confirmed cases with no deaths. Elsewhere, there were confirmed cases in Canada, UK, Spain, New Zealand, and Israel.