The Iceman would have been a good candidate but he was much to early. They (finally) found a sample of the 1918 'Spanish Flu' (Which originated in Kansas) virus in a biopsy from a WW1 soldier that had been 'filed away.'
I was unaware of the discovery of the organism that caused the "Spanish" flu. [I lost a grandmother and greatgrandmother to this disease; more people were killed by this disease in one province of India than died in both sides in World War I.]
I have heard a number of well informed experts opine that much of the virulence of this outbreak was due to a bacterium [in the Haemophilus genus as I recall] which occurred along with the influenza virus. Do you know if such an association was found and, if so, were any LD50 testings done?