Narrator: This is Science Today. New findings suggest the deadly 1918 influenza epidemic, which took a half a million lives in this country, may have in most cases, been caused by undetected tuberculosis, or TB. University of California, Berkeley demographer, Andrew Noymer, led the study.
Noymer: We noticed interestingly that after the 1918 flu, TB death rates declined very quickly. And we noticed that male TB death rates declined much more quickly than female TB death rates and this led us to our key finding, that in 1918 in the influenza epidemic, not only was this unusually high mortality, but men were also more susceptible than women.
Narrator: Men were also more susceptible to TB, a disease that kills slowly and primes the lungs for a bacterial infection, which Noymer says ultimately killed the 1918 flu victims.
Noymer: So, even though we don't have what a medical doctor would call "causal proof", we do have a plausible story behind the vital statistics.
Narrator: For Science Today, I'm Larissa Branin.