Russia is increasing patrols on its border with China and Mongolia after the countries reported suspected occurrences of the bubonic plague, as the world’s largest country seeks to keep the killer disease out.

Patrols aim to stop people from hunting marmots, which can carry the illness and are thought to have been the cause of the recent outbreak. Russian authorities have warned of the dangers of eating the rodent.

Occurrences of the plague have been found in the Chinese region of Inner Mongolia, and the Mongolian province of Khovd.

The bubonic plague is one of the plague’s three variants, and was responsible for killing up to 200 million people in the 14th Century, in what was called ‘the Black Death’. Symptoms of the disease include fever, headaches, and vomiting, and it is highly lethal if left untreated. Nowadays, there are about 650 cases every year. (RT)