The Plague

There are 3 different types of plague, all of which are caused by the bacteria Yersinia pestis and born in rodents such as rats, rabbits, prairie dogs, squirrels, and even domestic cats. The bacteria is spread primarily through the bites of fleas but can also be passed along by scratches or bites directly from the infected animal, in some rare cases handling an infected animal, or, in the case of Pneumonic plague, through the air we breathe.

The symptoms and speed of their appearance after infection differ for each type of plague:

Bubonic plague, in which the bacteria infects the lymph nodes, typically takes 2 - 5 days to show up after contact. Symptoms include:

Yersinia pestis 200x mag.

• Chills
• Fever
• Malaise (a general feeling of illness)
• Headache
• Muscle Pains
• Seizures
• Lymph glad swelling (usually in the groin but also in the armpits, neck or location of bite/scratch)

Pneumonic plague, mentioned above, effects the lungs and can be passed through the air. Symptoms can take as little as a day to appear but more typically take 2 - 3. Those symptoms include:

• Coughing/Severe coughing
• Difficulty breathing
• Fever
• Coughing up frothy blood mixed with mucus
• Chest pain especially when breathing deeply

Septicemic plague, arguably the most deadly of the plagues, can kill the infected before symptoms ever show up. If they do appear, they include:

• Abdominal pain
• Bleeding due to problems with clotting blood (in other words, persistant bleeding because a wound won't clot)
• Diarrhea
• Fever
• Nausea and vomiting

Source: A.D.A.M. Medical Encyclopedia, 2011. © 2011 A.D.A.M., Inc.

Figure 1: "Diagram of a flea, drawing using Hooke's microscope" (http://www.parrswood.manchester.sch.uk/faculties/science/hooke.html)
Figure 2: "Yersinia pestis 200x magnification with florescent label"
(http://upload.wikimedia.org/wikipedia/commons/1/15/Yersinia_pestis_fluorescent.jpeg)