One swarm recorded was 37 miles long and 25 miles wide.
China's Center for Disease Control took to social media to reassure citizens that chances of catching the communicable disease were "extremely low."
Two doses of the vaccine protected mice, rats and rabbits against inhalational anthrax and pneumonic plague.
When the steppe peoples entered Europe in a bid to leave the plague behind, they would have unwittingly introduced the bacterium to entirely new populations which had never encountered it.
The skeletons are suspected to be those of plague and starvation victims.
A sacred ritual that involves exhuming and rewrapping the remains of relatives could be aiding the spread of the disease.
The plague outbreak is a powerful enemy that cannot be stopped easily.
During Puzder's tenure as CEO, Carl's Jr. and Hardee's have faced more federal employment discrimination suits than any other major U.S. hamburger chain.
Poorly worded poll questions set up a plague-on-both-your-houses narrative.
What is considered a medieval disease by many is still present in several African countries.
'Plague' gives everyone's posts equal footing, allowing users to determine which content should go viral.