1. The Black Death

2. Bubonic Plague The plague is caused by the bacterium Yersinia pestis Millions of people in Europe died from the plague in the Middle Ages Bubonic Plague is contracted by humans when they are bitten by a rodent flea carrying the bacterium. It then spreads to the lymph nodes where is causes them to swell (armpits, neck & groin) The bacterium may spread to the bloodstream (septicemic plague) or the lungs (pneumonic plague).

4. Symptoms include: –Swollen lymph nodes –Red spots on the skin that turn black –Heavy breathing –Vomiting (bloody) –Aching limbs –Terrible pain caused by decaying tissue –Spasms when near death Kills about 50% of infected patients within 3-7 days Bubonic Plague

6. Pneumonic Plague If Bubonic plague spreads to a person’s lungs, it may develop into Pneumonic Plague Pneumonic plague can spread when an infected person coughs and aerosolizes the pathogen. Pneumonic plague is much more virulent than Bubonic Plague

7. Septicemic Plague The least common form of the plague can occur if the bacterium spreads to the bloodstream of a person with Bubonic or Pneumonic plague. This causes abnormal blood clotting throughout the body Leads to certain death

8. The Plague Today Bubonic plague is still common in rodent fleas today. If treated promptly infected patients can recover with the use of antibiotics. Prevalence of plague related deaths has declined greatly due to –Sanitation to reduce rodent populations –Use of antibiotics Approximately 1500-3000 people worldwide contract bubonic plague each year.

9. The Plague Today In the US, there are about 10-15 plague cases each year. Most of which occur in the Western states.