Jordan also considered Oxford's theory that the "purulent bronchitis" in British Army camps in 1916 and 1917 was the source. He rejected it for several reasons. The disease had flared up, true, but had not spread rapidly or widely outside the affected bases; instead, it seemed to disappear [3] . As we now know a mutation in an existing influenza virus can account for a virulent flare-up. In the summer of 2002, for example, an influenza epidemic erupted in parts of Madagascar with an extremely high mortality and morbidity; in some towns it sickened an outright majority -in one instance sixty-seven percent -of the population. But the virus causing this epidemic was an H3N2 virus that normally caused mild disease. In fact, the epidemic affected only thirteen of 111 health districts in Madagascar before fading away [4]. Something similar may have happened in the British base.