Bubonic plague is the form of plague that caused the black death and decimated the population of Europe. Bubonic plague is spread through infected fleas, or through contact with fluids and tissues of an infected person. The symptoms of bubonic plague, which manifest 2 to 6 days afer infection, are painfully swolen lymph nodes, or buboes, followed by and headache and fever. In primary cases, the lymph nodes are not initially involved, making the disease much more deadly becaues it is harder to diagnose. The symptoms of septicemic plague are blood poisoning, shock, and hemmorhaging.
Pneumonic plague can also be primary or secondary.
This form of the plage is the most dangerous for two reasons. Second, pneumonic plague can be spread through the air by droplets coughed up by infected persons. Symptoms include serious pneumonia, fever, and chills, and the incubation period is 1 to 3 days. Because the plague lives in fleas and rodents, it is impossible to completely erradicate the disease. Luckily, prevention measures can can be very effective.