The New World
When the Conquistadors and the other European settler's reached the New World, a major portion of the Native
populations died as a result of being exposed to Old World diseases from which they had no previous immunization.
During Pontiac's War, the British Army gave blankets to the Lenape which had been contaminated with smallpox. It is suspected
that biological warfare was used against Natives on other occasions, also.
World War II
The Japanese used biological warfare extensively during the Sino-Japanese War (1937-1945) and WWII (1939-1945), especially
against Chinese soldiers and civilians. The Japanese distributed foodstuffs contaminated with the plague, such as vegetables
and dumplings. They also contaminated water supplies with cholera and and the plague, resulting in over 580,000 deaths.
The Japanese also performed extensive research on the use of bioweapons and modes of dispersal. Much of this research
was conducted by the infamous
Unit 731, a division of the Imperial Japanese Army.