Table 2.
Transmission and reassortment events of human and swine influenza A viruses
| Subtype | Human | Swine | ||||||
|---|---|---|---|---|---|---|---|---|
| Genotype | Eventsa | N.b | Yearc | Genotype | Events | N. | Year | |
| H1N1 | [A, A, A, 1A, A, 1A, B, 1A] | First transmission from avian?[17] | 1 | 1918 (1) | [A, A, B, 1B, A, 1A, B, 1A] | Transmission from human [42] | 4 | 2004-2006 |
| [A, A, C, 1B, A, 1A, B, 1A] | Unknownd | 1 | 1936 | [A, A, C, 1A, A, 1A, A, 1A] | Unknownd | 1 | 1931 (4) | |
| [A, A, C, 1A, A, 1B, B, 1A] | Transmission from swined[43] | 1 | 1976 (2) | [A, A, C, 1A, A, 1A, B, 1A] | Unknownd | 1 | 1935 (5) | |
| [A, D, B, 1B, A, 1A, B, 1A] | Reassortant by H3N2 & H1N1 | 5 | 1978-1979 | [A, G, I, 1C, F, 1F, F, 1E] | Reassortant by EA & humand[44] | 1 | 1979 | |
| [B, A, C, 1A, A, 1B, A, 1A] | Transmission from CS | 4 | 1976-1991 | [B, D, C, 1A, A, 1B, A, 1A] | Reassortant by TRIG & CS [45] | 3 | 2004 | |
| [C, D, E, 1A, A, 1B, A, 1A] | Transmission from TRIG [46] | 1 | 2005 | [C, A, C, 1A, B, 1A, B, 1A] | Unknownd | 3 | 1931-1942 | |
| [C, D, E, 1B, A, 1A, A, 1A] | Reassortant by TRIG & H1N1 [37] | 3 | 2009 | [C, D, C, 1A, A, 1B, A, 1A] | Reassortant by TRIG & CS [45] | 1 | 2003 | |
| [C, A, C, 1A, B, 1A, B, 1A] | Unknownd | 2 | 1982-1987 | [C, D, E, 1B, A, 1A, A, 1A] | TRIG & human H1N1 [47] | 2 | 2005 | |
| [C, D, E, 1C, A, 1F, F, 1A] | TRIG & EA [35] | 1 | 2010 | |||||
| [C, F, E, 1D, H, 1E, E, 2B] | Transmission from avian [48] | 1 | 2002 | |||||
| [F, G, I, 1A, F, 1F, F, 1E] | Reassortant by EA & CS [49] | 1 | 2000 | |||||
| [F, G, I, 1A, A, 1B, F, 1E] | Reassortant by EA & CS [3] | 2 | 2001 | |||||
| [F, G, I, 1C, F, 1F, F, 1A] | Reassortant by EA & TRIG [9] | 10 | 2009 | |||||
| H1N2 | [A, D, B, 1B, A, 2A, B, 1A] | Reassortant by H3N2 & H1N1 [50,51] | 26 | 2002-2003 | [A, D, B, 1B, A, 2A, B, 1A] | Reassortant by H3N2 & human H1N1 [45] | 1 | 2003 |
| [B, A, C, 1A, A, 2A, A, 1A] | Reassortant by CS & H3N2 [49,52] | 4 | 1980-2004 | |||||
| [B, D, C, 1B, A, 2A, A, 1A] | Reassortant by TRIG & CS [45] | 2 | 2004 | |||||
| [C, D, E, 1A, A, 2A, F, 1A] | Reassortant by TRIG & EA [3] | 2 | 2003-2004 | |||||
| [F, G, I, 1A, A, 2A, F, 1E] | Reassortant by EA & CS [3] | 1 | 2001 | |||||
| [F, G, I, 1A, F, 2A, F, 1A] | Reassortant by EA & CS [9] | 1 | 2009 | |||||
| H2N1 | [A, A, B, 2B, A, 1A, B, 1A] | Reassortant by H1N1 & H2N2?d | 1 | 1977 | ||||
| H2N3 | [C, D, E, 2H, A, 3A, A, 1A] | Reassortant by TRIG & avian [53] H2N3 [53] | 2 | 2006 | ||||
| H3N1 | [C, D, E, 3A, A, 1B, A, 1A] | Reassortant by TRIG & CS [54,55] | 5 | 2004-2006 | ||||
| H3N2 | [A, A, A, 3A, A, 2A, B, 1A] | Reassortant by H1N1 & H3N2?d | 1 | 1968 | [A, D, B, 3A, A, 2A, A, 1A] | Reassortant by H3N2 & CS | 1 | 2002 |
| [C, D, E, 3A, A, 2A, A, 1A] | Transmission from TRIG [38] | 1 | 2005 | [F, G, I, 3A, A, 2A, F, 1A] | Reassortant by EA & CS [56] | 1 | 2004 | |
| [F, G, I, 3A, F, 2A, F, 1E] | Transmission from EA [57] | 1 | 1999 | |||||
| H3N3 | [C, F, E, 3C, H, 3A, E, 1D] | Transmission from avian [48] | 2 | 2001 | ||||
| H3N8 | [C, I, G, 3F, C, 8B, E, 1D] | Transmission from avian [58] | 2 | 2005-2006 | ||||
| H4N6 | [C, F, E, 4A, H, 6A, E, 1D] | Transmission from avian [59] | 1 | 1999 | ||||
| H5N1 | [G, G, E, 5J, F, 1G, F, 1E] | Transmission from avian [11,60] | 13 | 1997-1998 | [K, G, D, 5J, F, 1J, F, 1E] | Transmission from avian [61] | 9 | 2001-2004 |
| [K, G, D, 5J, F, 1J, F, 1E] | Transmission from avian [10,62,63] | 147 | 2003-2008 | |||||
| [L, G, D, 5J, F, 1J, F, 1E] | Transmission from avian | 1 | 2006 (3) | |||||
| H5N2 | [C, G, E, 5H, A, 2D, A, 2A] | Reassortant by TRIG & avian [64] | 1 | 2008 | ||||
| [G, G, D, 5H, F, 2D, F, 2A] | Transmission from avian [64] | 1 | 2008 | |||||
| H7N3 | [C, F, E, 7F, H, 3A, E, 1D] | Transmission from avian [65] | 1 | 2004 | ||||
| H7N7 | [G, G, D, 7A, F, 7D, F, 1E] | Transmission from avian [66] | 1 | 2003 | ||||
| H9N2 | [G, G, D, 9C, F, 2B, F, 1E] | Transmission from avian [67] | 1 | 2003 | [G, G, D, 9F, F, 2D, F, 1E] | Transmission from avian | 1 | 2004 |
| [G, G, E, 9C, F, 2B, F, 1E] | Transmission from avian [68] | 1 | 1999 | [K, G, E, 9C, F, 2B, F, 1E] | Transmission from avian [69] | 11 | 1998-2005 | |
| [G, G, E, 9B, F, 2E, F, 1E] | Transmission from avian [60] | 2 | 1999 | |||||
aEvents: possible transmission or reassortment events and most of them were previously reported. CS: classic swine; EA: Eurasian avian-like swine; TRIG: Triple reassortant swine.
bN.: the number of the relevant virus strains in FluGenome.
cYear: the isolation year of the relevant virus strains in FluGenome. If multiple strains have been isolated, the first and the last years are listed. The numbers in the round brackets following the years refer to some special virus strains in history: (1) A/Brevig Mission/1/1918; (2) A/New Jersey/1976; (3) A/Indonesia/CDC759/2006; (4) A/swine/1931; (5) A/swine/Ohio/23/1935.
dSome events are hard to exactly determined due to lack of full information about these old virus strains.