Pneumonic plague claimed a third victim in northwest China's Qinghai Province on Monday, Xinhua quoted local health authorities as saying. The victim was a 64-year-old man from the town of Ziketan, in Xinghai county in the Hainan Tibetan Autonomous Prefecture. The outbreak, which began July 30 and has caused a further nine people in the town to become ill, has already killed a 32-year-old herdsman and one of his neighbors, a 37-year-old man. Of the nine patients in quarantined, one is in a serious condition and another has developed symptoms of coughing and chest pain. Most of the affected townspeople are relatives of the first dead man. There has been no report of new infections. Medical staff are disinfecting the region and tracking down people who have been in close contact with those affected by the plague. The local government has quarantined the town and its vicinity. The area has adequate essential supplies and the quarantine has not disrupted the locals' lives. Those who have been in Ziketan and its vicinity since July 16 who show symptoms of fever and coughing have been ordered to report to the nearest hospital. The town covers 3,000 square kilometers and has a population of 10,000. Pneumonic plague is one of the deadliest infectious diseases; patients can die 24 hours after infection, said the World Health Organization.