蜜芽传媒

The black rat was introduced to Europe by man. But the black rats which came to western Europe on the ships of the crusaders were different. These rats came from ports in eastern Mediterranean where there was bubonic plague (the Black Death). The rats could not transmit the infection to man, but their fleas could. Some fleas are fussy and will only bite one type of animal, but tragically these fleas would feed on people as well as on rats. The fleas feed on rat blood. As they fed, they took the plague bacillus into them from infected rats, and when they bit another rat or human, they inadvertently passed the disease onto them.