Orthomyxoviridae
Name of pandemic Date Deaths Case fatality rate Subtype involved Pandemic Severity Index
1889-1890 flu pandemic ( Asiatic or Russian Flu ) 1889-1890 1 million 0.15% possibly H3N8 or H2N2 NA
1918 flu pandemic ( Spanish flu ) 1918-1920 20 to 100 million 2% H1N1 5
Asian Flu 1957-1958 1 to 1.5 million 0.13% H2N2 2
Hong Kong Flu 1968-1969 0.75 to 1 million < 0.1% H3N2 2
Russian flu 1977-1978 no accurate count N/A H1N1 N/A
2009 flu pandemic 2009-2010 105,700-395,600 0.03% H1N1 NA
Types -- Influenza A
Main article : Influenzavirus A Influenza A viruses are further classified , based on the viral surface proteins hemagglutinin ( HA or H ) and neuraminidase ( NA or N ) . Sixteen H subtypes ( or serotypes ) and nine N subtypes of influenza A virus have been identified . Diagram of influenza nomenclature Further variation exists ; thus , specific influenza strain isolates are identified by a standard nomenclature specifying virus type , geographical location where first isolated , sequential number of isolation , year of isolation , and HA and NA subtype . [ 11 ] [ 12 ] Examples of the nomenclature are : A/Brisbane/59/2007 ( H1N1 ) A/Moscow/10/99 ( H3N2 ) . The type A viruses are the most virulent human pathogens among the three influenza types and cause the most severe disease . The serotypes that have been confirmed in humans , ordered by the number of known human pandemic deaths , are : H1N1 caused `` Spanish flu '' in 1918 , `` Swine flu '' in 2009 . [ 13 ] H2N2 caused `` Asian Flu '' . H3N2 caused `` Hong Kong Flu '' . H5N1 is a pandemic threat . [ 14 ] H7N7 has unusual zoonotic potential . [ 15 ] H1N2 is endemic in humans and pigs [ citation needed ] . H9N2 , H7N2 , H7N3 , H10N7 .
Orthomyxoviridae (ὀρθός, orthós, Greek for straight; μύξα, mýxa, Greek for mucus) is a family of RNA viruses. It includes seven genera: Influenzavirus A, Influenzavirus B, Influenzavirus C, Influenzavirus D, Isavirus, Thogotovirus, and Quaranjavirus. The first four genera contain viruses that cause influenza in vertebrates, including birds (see also avian influenza), humans, and other mammals. Isaviruses infect salmon; the thogotoviruses are arboviruses, infecting vertebrates and invertebrates, such as ticks and mosquitoes. The four genera of Influenza virus, which are identified by antigenic differences in their nucleoprotein and matrix protein, infect vertebrates as follows: