Box 1. How virulent is 1918 flu?
From the following article:
The 1918 flu virus is resurrected
Nature 437, 794-795(6 October 2005)
doi:10.1038/437794a
50 times as many virus particles are released from human lung cells a day after infection with the 1918 virus as are released after exposure to a contemporary strain called the Texas virus.
13% of body weight is lost by mice 2 days after infection with 1918 flu; weight loss is only transient in mice infected with the Texas strain.
39,000 times more virus particles are found in mouse lung tissue 4 days after infection with 1918 flu than are found with the Texas virus.
All mice died within 6 days of infection with 1918 flu; none died from the Texas strain.
