A 25-year-old woman contracted the deadly disease after eating marmot meat. The woman and 19 of her close contacts have been placed in an isolation ward in a hospital in Khovd province in the west of Mongolia. Mongolia’s National Center for Zoonotic Diseases (NCZD) said the woman had eaten marmot meat that was infected with the bacteria Yersinia pestis.

Yersinia pestis is found in wild rodents and the fleas that feed off them.

There have been 22 suspected cases of bubonic plague in Mongolia this year.

Three patients this year have died as a result of the disease in Mongolia.

Sadly cases of bubonic plague have broken out in China also.

On Sunday in Yunnan in central China, a three-year-old boy died from the disease.

Menghai county in central China has now increased efforts to eradicate the disease by exterminating rodents that carry the transmitting fleas.

Russia has also taken steps to protect its citizens against bubonic plague outbreaks in its eastern provinces.

One outbreak of bubonic plague was recorded on the Ukok plateau in eastern Russia.

READ MORE: Bubonic plague PANIC: China declares disease emergency as cases rise

Pneumonic plague is a severe lung infection caused by the bacterium Yersinia pestis and is caught after inhaling airborne droplets from another infected person.

There is no available cure for pneumonic plague, although vaccines are being developed.

Left untreated the pneumonic plague is nearly always fatal.

The pneumonic plague was responsible for 50 million deaths during the Black Death of the 1300s.