Chinese authorities have reported an outbreak of pneumonic plague in Qinghai province, northwestern China.
According to reports by the BBC, thousands of people have been quarantined in the town of Ziketan, near Xinghai, following the death of a 32-year-old herdsman who showed symptoms of the disease.
A 37-year-old man, said to be a neighbour of the first victim, has also died.
The disease, which attacks the lungs, is highly virulent and requires treatment within 24 hours of the appearance of the first symptoms, which are fever, headache and breathlessness.
China is already battling to contain an outbreak of swine flu on the mainland.
The Foreign Office has not changed its travel advice to the country in response to the outbreak of pneumonic plague, but said it was keeping the situation under constant review.