Variant of the Same Bacteria That Caused the Bubonic Plague Strikes China

Blast from the Past: Plague Strikes China

August 5, 2009

ABC News - Over the weekend, news emerged that a variant of the same bacteria that caused the infamous" Black Death," or bubonic plague, in medieval Europe had claimed three lives in the Chinese province of Qinghai, prompting the government to quarantine the town of Ziketan, home to 10,000 people.

The bacteria responsible, Yersinia pestis, is the same bacteria that caused the bubonic plague, which wiped out millions of people in Europe in the fourteenth century.

While this form of the disease, known as pneumonic plague, spreads from human to human without needing rats or fleas for transmission, it is not the grave threat to humans it was in medieval times.

"In this form, the organism gets in the lung -- that allows it to be transmitted by coughing," explained Philip Alcabes, associate professor in the program in urban public health at Hunter College's School of Health Sciences and author of Dread: How Fear And Fantasy Have Fueled Epidemics From The Black Death To Avian Flu. "The problem with that is that it allows it to be transmitted directly from person to person."

Fleas will spread the bubonic plague when they bite rats, injecting the bacteria into the animal's bloodstream, but will bite humans when a rat is not available. In some cases, those bacteria will find a way into the lung, turning bubonic plague into the more contagious pneumonic plague.

"If it's in the person's bloodstream, that's called bacteremia. That goes to the lungs, and it could potentially seed the lung tissue, and the bacteria could set up shop there," said Dr. Howard Markel, professor of the history of medicine and of pediatrics and communicable diseases at the University of Michigan Medical School in Ann Arbor, who noted that the disease could also become pneumonic if aerosolized bacteria are inhaled.

"Pneumonic is the kind where you really get scared," he said. "You can spread it even more quickly, breathing on people in close, crowded areas."

While China quickly moved to quarantine the village, Markel and Alcabes questioned the appropriateness of that response...