was an intermediary, the rat flea, Xenopsylla cheopis (Shrewsbury 15). When the flea sucks blood from an infested rat, it picks up some plague bacilli that are carried in the rat's bloodstream. If the flea then hops to a new host, say another rat, it will transmit some of the bacilli to the new host while sucking blood.While the rat flea ordinarily prefers rat blood, it will suck the blood from other warm-blooded animals, including man, if rats are not available. That is when the plague becomes dangerous to man. It is particularly dangerous when men and rats live close together. (Ziegler 13).There are three different forms of the plague caused by Pasteurella pestis. The form the disease takes depends on where the bacilli collect in the body. (Shewsbury 26). The most common form is the bubonic plague. This disease is characterized by an extermely high fever, chills, and ultimately delirium and death. The bacilli collect in the lymph nodes, particularly those in the armpits and groin. The nodes swell and become extremely painful. One containing this disease, bubonic plague, usually comes to death within a week (Encarta).When an individual suffers an overwhelming invasion of plague bacilli, the germs may go directly into the bloodstream. Such infections are known as septicemic plague. Septicemia comes from the Greek word meaning putrid blood. This form of plague kills more quickly, commonly within three days. There are even stories of persons going to bed healthy and being dead the following morning due to the plague. The victim may die before the swelling and other characteristic signs of plague appear.In some cases purplish or blackish spots appear on the victim's skin. This symptom may account for the name Black Plague also. A third form of the plague is pneumonic plague. In this case the bacilli invades the lungs, which are called pneumons in Greek. Pneumonic plague can appear as a complication of bubonic plague, ju...
