A century before Ebola, SARS, or avian flu began making headlines, another invisible killer was carving a swath of death and fear across the Russian Empire: the plague. And even in an age that predated PCR and even Watson and Crick, the remarkable way the tsarist government set out to fight what was then an unknown organism could be a model for today's preventive strategies. "I thought I was being so creative for the last five years [by] suggesting that we look for zoonotic diseases independent of species bias," says veterinary pathologist Tracey McNamara, whose work on sick crows in 1999 helped lead to the identification of West Nile virus. "[The Russians] tried to detect disease threats before they spilled over into the human population."