Virus H1N1 de 1918
Virus de la gripe de 1918. (Volver a Cronología. Personas. Geografía. Fuentes.)
Tiene 8 genes y parece haber sido totalmente novedoso para el hombre, sin embargo, tiene que haber sido una evolución radical en humanos de la Gripe aviar, porque esta ha evolucionado muy poco en pájaros.
Viral sequence data now suggest that the entire 1918 virus was novel to humans in, or shortly before, 1918, and that it was not likely to have been a reassortant virus such as those that caused the 1957 and 1968 pandemics [102].
102. Rabadan R, Levine AJ, Robins H. Comparison of avian and human influenza A viruses reveals a mutational bias on the viral genomes. J Virol. 2006;80:11887–11891. [PMC free article] [PubMed]
Rather, the 1918 virus is an avian-influenza-like virus that appears to have been derived in toto from an unknown source [1,92,103]
1. Taubenberger JK, Reid AH, Lourens RM, Wang R, Jin G, Fanning TG. Characterization of the 1918 influenza virus polymerase genes. Nature. 2005;437:889–893. [PubMed]
92. Reid AH, Fanning TG, Janczewski TA, Lourens RM, Taubenberger JK. Novel origin of the 1918 pandemic influenza virus nucleoprotein gene. J Virol. 2004;78:12462–12470. [PMC free article] [PubMed]
103. Reid AH, Taubenberger JK, Fanning TG. Evidence of an absence: the genetic origins of the 1918 pandemic influenza virus. Nat Rev Microbiol. 2004;2:909–914. [PubMed]
because its eight genome segments differ from contemporary avian influenza genes, especially at synonymous sites. Influenza virus gene sequences from a number of fixed specimens of wild birds collected circa 1918 showed little difference from avian viruses isolated today and consequently did not suggest these birds were the source [104,105].
104. Fanning TG, Slemons RD, Reid AH, Janczewski TA, Dean J, Taubenberger JK. 1917 avian influenza virus sequences suggest that the 1918 pandemic virus did not acquire its hemagglutinin directly from birds. J Virol. 2002;76:7860–7862. [PMC free article] [PubMed]
105. Reid AH, Fanning TG, Slemons RD, Janczewski TA, Dean J, Taubenberger JK. Relationship of pre-1918 avian influenza HA and NP sequences to subsequent avian influenza strains. Avian Dis. 2003;47 (Suppl 3):921–925. [PubMed]
These findings also suggest that avian viruses undergo little directed evolution in their natural hosts even over long periods.
