Definition

2009 H1N1 influenza is a highly contagious respiratory infection among pigs, which is sporadically transmitted to human populations. The pandemic that started in spring 2009 was caused by a novel H1N1 subtype of influenza A View image in North America. 2009 H1N1 influenza causes respiratory illness similar to seasonal influenza. Unlike avian influenza, swine influenza, upon infecting humans, is easily transmissible from person to person. The World Health Organization (WHO) declared the 2009 novel H1N1 swine influenza pandemic to be over in August 2010. [1] However, it is presumed that the H1N1 virus that emerged in 2009 continues to circulate along with seasonal strains of influenza. [2] [CDC: Weekly Influenza Surveillance Report]