A 15-year-old boy died of bubonic plague in western Mongolia, the country’s national news agency reported. The Health Ministry said tests confirmed the teenager died of the plague, which he contracted from an infected marmot, according to the Montsame News Agency. The case prompted the Mongolian government to impose a quarantine on part of Gobi-Altai province. Montsame said 15 people who had contact with the boy were isolated. The disease, which humans can contract from fleas on infected animals or through contact with contaminated fluid or tissue from an animal that died from the disease, attacks the lymph nodes, leading to swelling, pain and pus formation. Between 50 and 60 per cent of cases are fatal if left untreated, but it is easily cured by common antibiotics. In an unrelated case in neighbouring China, a patient who was infected with plague in the northern region of Inner Mongolia is improving, according to China’s official Xinhua News Agency. It said 15 people who had close contact with the patient were released from quarantine on Sunday. The agency said the government ended its top-level emergency response. An official announcement earlier said a warning for the public in the Bayannur region of Inner Mongolia to avoid eating marmot and to report dead animals would last through the end of 2020.