Emergency workers intercepted the domestic flight at the airport in the capital Ulaanbaatar, after a husband and wife died of the contagious disease in the region where the flight originated. According to reports they had eaten contaminated meat from a marmot, a large squirrel. 

 

Eleven passengers from the west of the country were held at the airport and sent immediately for hospital checks while others were examined at the airport. Paramedics in anti-contamination suits boarded the flight from provincial outposts Bayan, Ulgii and Khovd as soon as it landed. 

 

Some 158 people have been put under intensive medical supervision in Bayan-Ulgii province after coming into contact directly or indirectly with the couple who died. 

 

Some frontier check points with Russia are reported to have been closed leading to foreign tourists being stranded in Mongolia.    

 

A man named Citizen T, aged 38, died on April 27 after hunting and eating marmot meat. His pregnant wife, 37, died three days later, reported The Siberian Times, leaving their four children orphaned.  

 

Top medic Dr N. Tsogbadrakh said the plague had 'affected the man's stomach' after he ate the meat and gave it to his wife. 

 

The bubonic plague can kill an adult in less than 24 hours if not treated in time, according to the World Health Organisation. It is caused by the bacterium Yersinia pestis, which is usually found in small mammals and their fleas. The bacterium was linked to the Black Death which wiped out more than a third of Europe's population in the 14th century and to subsequent plague outbreaks.  

 

The disease is now treatable with antibiotics but hundreds of people have died of it around the world in recent years.   

 

Since the 1990s, most human cases have occurred in Africa, according to world health bosses.  

 

What is the bubonic plague and how does it spread? 

Plague is an infectious disease caused by the bacterium Yersinia pestis, which is carried by fleas and transmitted between animals. The bubonic plague - the most common form - is caused by the bite of an infected flea and can spread through contact with infectious bodily fluids or contaminated materials.   

 

It devastated Europe in the Middle Ages, most notably in the Black Death of the 1340s which killed a third or more of the continent's population. After the Black Death plague became a common phenomenon in Europe, with outbreaks recurring regularly until the 18th century. 

 

When the Great Plague of 1665 hit, a fifth of people in London died, with victims shut in their homes and red crosses painted on the door. 

 

Bubonic plague has almost completely vanished from the rich world, with 90 per cent of all cases now found in Africa.  It is now treatable with antibiotics, as long as they are administered quickly.  Still, there have been a few non-fatal cases in the U.S., with an average of seven reported a year, according to disease control bosses. 

 

From 2010 to 2015 there were 3,248 cases reported worldwide, including 584 deaths, says the World Health Organisation. 

 

Without antibiotics, the bubonic strain can spread to the lungs – where it becomes the more virulent pneumonic form.  Pneumonic plague, which can kill within 24 hours, can then be passed on through coughing, sneezing or spitting.  

By WILL STEWART FOR MAILONLINE