Black death plague reappears in China

One of human history’s most dreaded diseases has reappeared in China.

Two people are being treated for the pneumonic plague in the Chinese province of Inner Mongolia. The latest cases follow the deaths of a Mongolian couple earlier this year from the bubonic plague, according to CNN.

The two recent patients are being treated by doctors in Beijing, and authorities have reportedly imposed preventive control measures.

The pneunomic plague is contracted by fleas.

According to the Atlanta-based Centers for Disease Control and Prevention, pneumonic plague is the most serious form of the disease and the only plague that can be spread from person to person. Symptoms include fever, headache, weakness and fast-developing pneumonia.

The bubonic plague usually comes from the result of an infected flea bite.

Earlier this year, the Mongolian couple who died from the bubonic plague had eaten the raw kidney of a marmot, according to CNN.

A couple in Mongolia died from the bubonic plague after eating raw marmot meat.

In medieval Europe, the plague killed about 50 million people. The plague first was introduced into the United States in 1900, the CDC said. Between 1900 and 2012, 1,006 people contracted the plague in the U.S. More than 80% of American plague cases have been bubonic.

The pneunomic plague is contracted by fleas.

An average of seven human plague cases are reported each year, with more than 50% occurring in people ages 12-45.

Before the introduction of antibiotics, about 66% of people in the U.S. died from the plague. Today, that number is down to 11%.