When there is a dense population of both humans and rats, the probability of a disastrous pandemic increases due to the dense community, yet compact, shrunk amount of land, which is known as a ‘plague focus’ or a ‘plague reservoir’. To that end, the black rat (‘ship rat’ or ‘house rat’) was the primary suspect for the spread of disease since they lived in close quarters to society. Consequently, within ten to fourteen days Yersinia pestis would contaminate the rat colony, which would leave a plethora of Xenopsylla cheopis without a host. Nonetheless, after three days, the rat fleas would transition their source of food from the black rat to a human. As a result of the flea bite, the contagion would affect the host [human] by draining into
