There have been three great plague pandemics in human history caused by the bacterium Y. pestis, spreading from Siberia and Mongolia, across Asia, and into Europe, the Middle East, and Africa. The first began in A.D. 541 within the Roman Empire, lasted two centuries, and was dubbed the Justinianic Plague. The second, the Black Death, spread from Asia into Italy in 1346 and persisted for 400 years, infecting most of the European population with such devastating outcome—50 million people died on a continent then inhabited by 80 million—that for centuries historians referred to it as the Great Mortality. The third pandemic began in the 1850s in China, spreading across Asia with such ferocity that India, alone, lost 20 million people.
The Real Reason to Panic About China's Plague Outbreak
It's not the disease that's worrisome—it's the Chinese government's response to it.