Plague is another great disease of antiquity. The plague was used as a biological weapon for the first time in the 14th century. The Tartar Army laid siege to the walled city of Kaffa. The attackers catapulted plague ridden corpses into the city. The plague that followed forced the defenders to surrender the city.
Plague is spread by flea infested rats.
In the 1930's and 40's the Japanese army filled ceramic bombs with infected fleas and dropped them on China. This created a plague epidemic in China and Manchuria. Plague spreads easily, kills quickly, and leaves behind terror and death. Death from plague would occur two to five days after the onset of symptoms. Plague is very contagious.