The story comes from the Peoples Daily/Xinhua press release, and there does not appear to be independent reporting.
The BBC has reported for two days on cases of pneumonic plague in a remote area of western China, said to be inhabited primarily by Tibetans. Although plague can be transmitted to humans via insect bites (due to reservoirs of infected animals, such as prairie dogs in the American southwest, which were bitten first) this form of plague is bubonic, not pneumonic. Pneumonic plague is transmitted via the airborne route, is much less common, and has been studied as a biological weapon.
A second man has died of pneumonic plague in a remote part of north-western China where thousands of people have been quarantined.
The man was identified by Chinese state media as a neighbour aged 37 of the first victim, who was 32, in Ziketan, near Xinghai in Qinghai Province.
The sparsely populated area is mostly inhabited by Tibetans.
Pneumonic plague, which attacks the lungs, can spread from person to person, or from animals to people.