An influenza pandemic is an epidemic of an influenza virus that spreads across a large region (either multiple continents or worldwide) and infects a large proportion of the population. There have been six major influenza epidemics in the last 140 years, with the 1918 flu pandemic being the most severe; this is estimated to have been responsible for the deaths of 50–100 million …

The 2009 swine flu pandemic, caused by the H1N1 influenza virus and declared by the World Health Organization (WHO) from June 2009 to August 2010, is the third recent flu pandemic involving the H1N1 virus (the first being the 1918–1920 Spanish flu pandemic and the second being the 1977 Russian flu). The first two cases were discovered independently in the United …

A gripe espanhola, [nota 1] também conhecida como gripe de 1918, [nota 2] foi uma vasta e mortal pandemia do vírus influenza.De janeiro de 1918 a dezembro de 1920, infectou uma estimativa de 500 milhões de pessoas, cerca de um quarto da população mundial na época. [5] Estima-se que o número de mortos esteja entre 17 milhões [6] e 50 milhões, e possivelmente …