Those who spend too much time talking to me will know that I've become pathologically preoccupied with respiratory infections since moving to Tucson. From my discovery of our local treat Valley Fever, to postal anthrax, to SARS, I've had a series of unhealthy fixations. When I read things like W.H.O. regional director Dr. Shigeru Omi's dire warning about avian flu, however, I'm reminded that panic spreads faster than the reasons for it. Nevertheless, my chest has tightened several degrees over the past hour. Perhaps it's time to revisit my onetime obsession with the pandemic of 1918-1919.